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EK-RM023-SV-001

June 1978

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Document:	RM02/03 Disk Subsystem Service Manual
Order Number:	EK-RM023-SV
Revision:	001
Pages:	213
Original Filename:	EK-RM023-SV-001_RM02_03_Service_Jun78.pdf

OCR Text

EK-RM023-SV-001

RM02/03 Disk Subsystem Service Manual

digital equipment corporation • maynard, massachusetts

1st Printing, June 1978

Copyright © 1978 by Digital Equipment Corporation
The material in this manual is for informational purposes and is
subject to change without notice.
Digital Equipment Corporation assumes no responsibility for any
errors which may appear in this manual.

Printed in U.S.A.

This document was set on DIGITAL's DECset-8000 computerized
typesetting system.

The following are trademarks of Digital Equipment Corporation,
Maynard, Massachusetts:
DIGITAL
DEC

PDP
DECUS
UNIBUS

D ECsystem-l 0
DECSYSTEM-20
DIBOL
EDUSYSTEM
VAX
VMS

MASSBUS
OMNIBUS
OS/8
RSTS
RSX
lAS

CONTENTS
Page
PREFACE
CHAPTER 1

INTRODUCTION

1.1
1.1.1
1.1.2
1.2
1.2.1
1.2.2
1.2.4
1.2.5
1.3

MAINTAINABILITY ........................................................................................ 1-1
Scope of Manual .......................................................................................... 1-1
RM02/03 Hardware Maintenance Plan ........................................................ 1-1
RESOURCES ...................................................................................................... 1-1
Related Documentation ............................................................................... 1-1
Special Tools ................................................................................................ 1-2
Initial Spares ................................................................................................ 1-2
Cable List ..................................................................................................... 1-6
Diagnostics .................................................................................................. 1-7
PREVENTIVE MAINTENANCE ...................................................................... 1-8

CHAPTER 2

INSTALLATION

2.1
2.2
2.2.1
2.2.1.1
2.2.1.2
2.2.1.3
2.2.1.4
2.2.1.5
2.2.1.6
2.2.1.7
2.2.1.8
2.2.1.9
2.2.1.10
2.2.2
2.3
2.4
2.4.1
2.4.2
2.4.2.1
2.4.2.2
2.4.2.3
2.4.2.4

INTRODUCTION .............................................................................................. 2-1
SITE PREPARATION AND PLANNING ......................................................... 2-1
Environmental Considerations ..................................................................... 2-1
Cleanliness ........................................................................................... 2-1
Space Requirements ............................................................................. 2-2
Floor Loading ...................................................................................... 2-3
Heat Dissipation .................................................................................. 2-3
Acoustics .............................................................................................. 2-3
Temperature ......................................................................................... 2-3
Relative Humidity ................................................................................ 2-3
Altitude ................................................................................................ 2-3
Altitude/Mechanical Shock .................................................................. 2-3
Power and Safety Precautions ............................................................... 2-3
AC Power Wiring ......................................................................................... 2-4
DRIVE UNPACKING AND INSPECTION PROCEDURE ............................. 2-4
RHII CONTROLLER INFORMATION ......................................................... 2-12
Mechanical ................................................................................................. 2-12
Electrical .................................................................................................... 2-14
Power Cable Connections ................................................................... 2-14
Unibus Cable Connections ................................................................. 2-14
Massbus Cables .................................................................................. 2-15
AC LO, DC LO .................................................................................. 2-20

1.2.3

111

CONTENTS (Coot)
Page
2.4.3
2.4.3.1
2.4.3.2
2.4.3.3
2.4.3.4
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.5.1
2.5.5.2
2.5.5.3
2.5.5.4
2.5.5.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.7
2.7.1
2.7.2
2.7.2.1
2.7.2.2
2.7.2.3
2.7.3
2.7.3.1
2.7.3.2
2.7.3.3
2.7.4
2.7.4.1
2.7.4.2
2.7.4.3
2.7.4.4
2.8
2.8.1
2.8.2
2.8.2.1
2.8.2.2
2.8.2.3
2.8.2.4

Jumper Configurations ............................................................................... 2-20
BCT Module (M7295) ........................................................................ 2-20
DBC Module (M7294) ........................................................................ 2-25
CSR Module (M7296) ........................................................................ 2-26
RH 11 Installation Checklist. ............................................................... 2-26
RH70 CONTROLLER INSTALLATION PROCEDURE (RWM03) ............... 2-27
Mechanical ................................................................................................. 2-27
Electrical .................................................................................................... 2-27
Module Locations ...................................................................................... 2-27
Massbus Cables .......................................................................................... 2-27
BCT and MDP Jumper Configurations ....................................................... 2-30
Register Selection ............................................................................... 2-30
BR I...evel Interrupt ............................................................................. 2-31
Vector Address Jumpers ..................................................................... 2-31
Maintenance Jumpers MDP Module (M8150) .................................... 2-31
Light-Emitting Diodes (LEDs) ........................................................... 2-32
CABLING PROCEDURES .............................................................................. 2-34
Ground Cabling ......................................................................................... 2-34
BC()6S Cable Preparation ........................................................................... 2-34
Single-Port Cabling Procedure .................................................................... 2-37
Dual-Port Cabling Procedure ..................................................................... 2-41
Power Sequence Cabling ............................................................................. 2-42
SUBSYSTEM CHECKOUT PROCEDURE ..................................................... 2-44
Subsystem Power Up .................................................................................. 2-44
Installation of the Field Test Unit ............................................................... 2-45
General Description ........................................................................... 2-45
.Tester Installation ............................................................................... 2-46
Controls and Indicators ...................................................................... 2-49
Operation of the Field Test Unit (FTU) ...................................................... 2-61
General Description ........................................................................... 2-61
Preliminary Setup ............................................................................... 2-61
Operating Procedures ......................................................................... 2-62
Head Alignment Procedure ......................................................................... 2-70
Installation of Head Alignment Card .................................................. 2-70
Preliminaries for Head Check or Alignment. ....................................... 2-72
Head Alignment Check ....................................................................... 2-74
Performing Head Alignment ............................................................... 2-78
FIELD ACCEPTANCE PROCEDURE ............................................................ 2-80
Introduction ............................................................................................... 2-80
Error Definitions/Rates ............................................................................. 2-80
Hard Errors ........................................................................................ 2-80
Soft Errors .......................................................................................... 2-80
Pack-Attributable Errors .................................................................... 2-80
Seek Errors ......................................................................................... 2-81

CONTENTS (Coot)
Page
2.8.3
2.8.4

Field Acceptance Test ................................................................................. 2-81
Diagnostic Programs .................................................................................. 2-82

CHAPTER 3

PARTS REMOVAL AND REPLACEMENT

3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9

LOCATION OF OUTER SKINS ........................................................................ 3-1
FRONT DOOR ................................................................................................... 3-3
FRONT BEZEL .................................................................................................. 3-4
DRIVE TOP COVER .......................................................................................... 3-5
CABINET REAR COVER .................................................................................. 3-6
SIDE PANELS .................................................................................................... 3-7
PACK ACCESS COVER ..................................................................................... 3-8
DECK MAINTENANCE POSITION ................................................................ 3-8
POWER SUPPLY MODULES ......................................................................... 3-10
42 V Supply and Emergency Retract (AIAOI) ............................................. 3-11
12 and 20 V Supply (A lA02) ....................................................................... 3-12
5 V Supply (AIA03) .................................................................................... 3-12
BLOWER MOTOR ASSEMBLY (AIBM1) ...................................................... 3-12
PRIMARY FILTER .......................................................................................... 3-15
ABSOLUTE FILTER ........................................................................................ 3-15
START TRIAC (AIK5) ..................................................................................... 3-17
RUN TRIAC (AIK1) ........................................................................................ 3-19
LOGIC CHASSIS ASSEMBLY (A2) ................................................................. 3-19
CONTROL PANEL ASSEMBLY ..................................................................... 3-24
POWER AMPLIFIER ASSEMBLY (A3A04) .................................................. .3-24
TRACK SERVO PREAMPLIFIER (A3A05) .................................................... 3-26
DRIVE BELT .................................................................................................... 3-27
Adjustment ................................................................................................. 3-27
Removal Procedure .................................................................................... 3-29
Repla,cement Procedure .............................................................................. 3-29
DRIVE MOTOR AND BRAKE ASSEMBLY ADJUSTMENT
(A3DM1, A3HB1) .............................................................................................. 3-29
SPINDLE ASSEMBLY ..................................................................................... 3-32
Adjustment ................................................................................................. 3-32
Removal Procedure .................................................................................... 3-33
Replacement Procedure .............................................................................. 3-34
SPINDLE LOCKSHAFT REPAIR ................................................................... 3-34
STATIC GROUND SPRING ADJUSTMENT ................................................ 3-36
SPEED TRANSDUCER (A3L 1) ....................................................................... 3-38
Adjustment ................................................................................................. 3-38
Removal Procedure .................................................................................... 3-38
Replacement Procedure .............................................................................. 3-38
VELOCITY TRANSDUCER (A3L2) REMOVAL AND REPLACEMENT
PROCEDURE ................................................................................................... 3-39

3.9.1

3.9.2
3.9.3
3.10
3.11
3.12
3.13
3.14
3.15
3.16
3.17
3.18
3.19
3.19.1
3.19.2
3.19.3
3.20
3.21
3.21.1
3.21.2
3.21.3
3.22
3.23
3.24
3.24.1
3.24.2
3.24.3
3.25

CONTENTS (Coot)
Page
3.26
3.26.1
3.26.2
3.27
3.28
3.29
3.30
3.31
3.31.1
3.32
3.32.1
3.32.2

PACK COVER SOLENOID (A3L3) ADJUSTMENT ...................................... 3-40
Old Style Solenoid Adjustment ................................................................... 3-40
New Style Solenoid Adjustment .................................................................. 3-42
RAIL BRACKET ASSEMBLY ......................................................................... 3-42
CARRIAGE AND COIL ASSEMBLY ............................................................. 3-43
FLEX LEAD ASSEMBLY ADJUSTMENT ..................................................... 3-43
HEADS LOAD SWITCH (A352) ADJUSTMENT ........................................... 3-43
MAGNET ASSEMBLY ADJUSTMENT ......................................................... 3-45
Removal/Replacement Procedure .............................................................. 3-46
HEAD ARM ASSEMBLY ................................................................................ 3-46
Repair ........................................................................................................ 3-46
Head Inspection ......................................................................................... 3-47

CHAPTER 4

ADJUSTMENT PROCEDURES

4.1
4.2

VELOCITY GAIN ADJUSTMENT WITH FTU .............................................. .4-1
GENERAL VOLTAGE ADJUSTMENTS ......................................................... 4-1

CHAPTER 5

FAULT ISOLATION

5.1
5.1.1
5.1.2
5.1.2.1
5.1.2.2
5.1.2.3
5.1.2.4
5.1.3
5.1.3.1
5.1.3.2
5.1.3.3
5.1.3.4
5.1.4
5.1.4.1
5.1.4.2
5.1.4.3
5.1.4.4
5.2
5.3
5.4
5.5
5.6
5.6.1
5.6.2
5.6.3
5.6.4

USING THE FAULT ISOLATION GUIDES .................................................... 5-1
Introduction ................................................................................................. 5-1
General Information .................................................................................... 5-1
Safety ................................................................................................... 5-1
FRU Locations .................................................................................... 5-3
Power Distribution ............................................................................... 5-5
Miscellaneous ....................................................................................... 5-8
Initial Fault Analysis .................................................................................. 5-10
Introduction ....................................................................................... 5-10
Initial Fault Analysis - RH Controller ................................................ 5-10
Initial Fault Analysis - Adapter .......................................................... 5-10
Initial Fault Analysis - Drive .............................................................. 5-10
Using The Guides ....................................................................................... 5-10
Introduction ....................................................................................... 5-10
FIG Usage Guide ............................................................................... 5-10
FIG Test Point Locator ...................................................................... 5-12
FIG Test Point Procedures ................................................................. 5-13
FAULT ISOLATION GUIDE NO. 1 ................................................................ 5-18
FAULT ISOLATION GUIDE NO. 2 ................................................................ 5-33
FAULT ISOLATION GUIDE NO. 3 ................................................................ 5-37
FAULT ISOLATION GUIDE NO. 4 ................................................................ 5-49
ADVANCED TROUBLESHOOTING ............................................................. 5-51
Introduction ............................................................................................... 5-51
DCK and ECH Error Descriptions ............................................................. 5-51
Data Check Fault Isolation Guide .............................................................. 5-52
Error Tests ................................................................................................. 5-54
vi

FIGURES
Figure No.

2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2-18
2-19
2-20
2-21
2-22
2-23
2-24
2-25
2-26
2-27
2-28
2-29
2-30
2-31
2-32
2-33
2-34
2-35
2-36
2-37
2-38
2-39
2-40
2-41
3-1
3-2

Title

Page

Disk Subsystem Space Requirements .................................................................... 2-2
Approved Electrical Plugs and Receptacles ........................................................... 2-4
Shipping Package ................................................................................................. 2-5
Front Door Removal ........................................................................................... 2-6
Front Bezel Location ............................................................................................ 2-7
Rear Cover Removal ............................................................................................ 2-7
Side Panel Mounting Screws ................................................................................. 2-8
Deck Maintenance Position ................................................................................ 2-10
Location of Actuator Holding Pin ...................................................................... 2-11
Location of Rear Deck Holding Screw ................................................................ 2-12
RH II Module U~ilization ................................................................................... 2-13
Single-Port Unibus Configuration ...................................................................... 2-16
Dual-Port Configuration - Memory on Unibus B ............................................... 2-17
Dual-Port Configuration - Memory and Processor on Unibus B ......................... 2-18
Massbus Cable System Configuration ................................................................. 2-19
Typical Power Fail Configuration for RH 11 and Options Mounted In
Same Expander Box ........................................................................................... 2-21
Typical Power Fail Configuration for Two RHlls Mounted in Same
Expander Box ..................................................................................................... 2-22
Typical Power Fail Configuration for RH11 and CPU Mounted in
Processor Box ..................................................................................................... 2-23
RH70 Module Utilization Chart ......................................................................... 2-28
RH70 Massbus Cable Connections ..................................................................... 2-29
LED Physical Locations ..................................................................................... 2-33
Grounding Studs and Cables .............................................................................. 2-35
BC06S Cable Preparation ................................................................................... 2-36
Module Shall be in Slot 8 .................................................................................... 2-38
BC06S Massbus Cable Connection ..................................................................... 2-40
Terminator Installation ...................................................................................... 2-41
Dual Port Cabling .............................................................................................. 2-42
Power Sequence Jumper ..................................................................................... 2-43
Daisy-Chain Power Sequence ............................................................................. 2-44
FTU Power Supply Layout ................................................................................. 2-47
FTU Power Supply Wiring Diagram .................................................................. 2-48
Tester I/O Cables ............................................................................................... 2-50
Head Alignment Connections ............................................................................. 2-51
TB3A2 Control Panel ......................................................................................... 2-52
Display Select Switch .......................................................................................... 2-55
Track Format ..................................................................................................... 2-56
Head Alignment Connections ............................................................................. 2-71
Head Alignment Card ........................................................................................ 2-72
Head Alignment Cable ....................................................................................... 2-75
Head Arm Alignment ......................................................................................... 2-77
Balanced Dibit Pattern ....................................................................................... 2-78
Location of Outer Skins ....................................................................................... 3-2
Front Door Removal ........................................................................................... 3-3

vii

FIGURES (CONT)
Figure No
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-26
3-27
3-28
3-29
3-30
3-31
3-32
3-33
4-1
4-2
4-3
4-4
5-1
5-2
5-3
5-4
5-5
5-6
5-7

Title

Page

Front Bezel Location ............................................................................................ 3-4
Drive Top Cover .................................................................................................. 3-5
Rear Cover Removal ............................................................................................ 3-6
Side Panel Mounting Screws ................................................................................. 3-7
Deck Maintenance Position .................................................................................. 3-9
Power Supply Assembly ..................................................................................... 3-1 0
±42 Volt Supply ................................................................................................. 3-11
12 and 20 Volt Supply ......................................................................................... 3-12
5 Volt Supply ...................................................................................................... 3-13
Blower Motor Replacement ................................................................................ 3-14
Absolute Filter Removal .................................................................................... 3-16
Start Triac .......................................................................................................... 3-18
Run Triac ........................................................................................................... 3-20
Logic Chassis (Old) ............................................................................................ 3-21
Logic Chassis (New) ........................................................................................... 3-22
Control Panel Assembly ..................................................................................... 3-25
Power Amplifier ................................................................................................. 3-26
Drive Belt Adjustments ...................................................................................... 3-28
Drive Motor and Brake Assembly ...................................................................... 3-31
Spindle to Carriage Alignment. ........................................................................... 3-33
Spindle Assembly ............................................................................................... 3-35
Static Ground Spring .......................................................................................... 3-37
Speed Transducer Adjustment ............................................................................ 3-39
Velocity Transducer Replacement ..................................................................... .3-40
Pack Cover Solenoid Adjustment ....................................................................... 3-41
Rail Bracket Assembly ....................................................................................... 3-42
Carriage and Coil Assembly ................................................................................ 3-43
Head Loaded Switch Replacement ..................................................................... 3-44
Magnet Assembly ............................................................................................... 3-45
Head Replacement - Left Side View ................................................................... 3-48
Head Replacement - Right Side View ................................................................. 3-49
Velocity Gain Waveform ...................................................................................... 4-2
Velocity Gain Adjustment ....................................................................................4-3
Power Supply Test Pins ........................................................................................4-4
5 Volt Adjustments ...............................................................................................4-5
Physical Location Codes ...................................................................................... 5-2
Power Distribution System ................................................................................... 5-6
FIG Determination Flow Diagram ..................................................................... 5-11
Servo Dibits ....................................................................................................... 5-15
+ Track Servo Signal .......................................................................................... 5-16
CYL Detect Signals ............................................................................................ 5-16
Fault Indicators on Edge of A2A04 Card ............................................................ 5-23

viii

TABLES
Table No.
1-1
2-1
2-2
2-3
2~4

2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
1-14
2-15
2-16
2-17
2-18
5-1
5-2
5-3
5-4
5-5
5-6
5-7

Title

Page

RM02/03 Documentation .................................................................................... 1-2
Subsystem Configurations .................................................................................... 2-1
RH 11 /RM02 Register Address Jumper Configurations ...................................... 2-24
RH 11 /RM02 Jumper Configurations ................................................................. 2-24
RH 11 /RM02/RPxx Mix Jumper Configurations ............................................... 2-24
Interrupt Vector Jumper Configurations ............................................................. 2-25
Massbus Cable System Configurations ............................................................... 2-30
RH70 Register Address Jumper Configurations .................................................. 2-30
RH70 Register Select Jumper Configurations ..................................................... 2-31
RH70 Vector Address Jumper Configurations .................................................... 2-32
Port Transceiver Module Status .......................................................................... 2-39
Backplane Jl Connector ..................................................................................... 2-39
Port Select Switch Positions ................................................................................ 2-39
Backplane Serial Numbers .................................................................................. 2-40
Plug Valid Tndication
.. ., ..... " .............. .,. " ............................ 2-54
FTU Test Points ................................................................................................. 2-60
Trouble Analysis ................................................................................................ 2-65
Head Alignment Card Switches and Indicators ....................................... " .......... 2-73
Error Conditions ................................................................................................ 2-81
Physical Location Codes ...................................................................................... 5-4
Checking AC Inputs to Power Supplies ................................................................ 5-7
Check DC Voltages .............................................................................................. 5-7
Typical Power Supply Failure Symptoms ............................................................. 5-8
Module and Subassembly DC Voltage Utilization ................................................ 5-9
Test Point Locator .............................................................................................. 5-12
Speed Pulse Path Test Points .............................................................................. 5-28

PREFACE

The RM02/03 Disk Subsystem Service Manual is designed to aid field personnel in installing, maintaining and repairing the RM02 or RM03 Disk Subsystem.
The first chapter of the book is an introduction to this manual. It contains the maintenance philosophy, as well as a list of additional resources (tools, spares, diagnostics, etc.). This chapter also contains
a preventive maintenance schedule.
Chapter 2 describes the procedures to follow when installing an RM02 or an RM03 drive, and also
contains a description of the TB3A2 Field Test Unit (FTU).
Chapter 3 details removal and replacement procedures for the Field Replaceable Units (FRUs) in the
drive, and Chapter 4 describes several adjustment procedures that field personnel may have to perform.
Chapter 5 is designed to enable service personnel to troubleshoot the RM02 or RM03. This is done by
following a step-by-step procedure known as a Fault Isolation Guide (FIG). Instructions on the use of
the FIGs, as well as the Fault Isolation Procedures (FIPs) that accompany them, are included in
Chapter 5.
Table 1-1 contains a list of additional documentation relevant to the RM02/03 Disk Subsystem.

CHAPTER 1
INTRODUCTION

1.1

MAINTAINABILITY

1.1.1 Scope of Manual
This manual contains information concerning the installation, operation and servICIng of the
RM02/03 Disk Subsystem. It was designed for use by trained DIGITAL Field Service and customer
maintenance personnel.
1.1.2 RM02/03 Hardware Maintenance Plan
The primary maintenance strategy calls for using on-line software (error logging, etc.) and/or
DECXII to isolate problems to the failing option level. Off-line diagno~ti~~ (XXDP) are used tu
isolate the problem to the adapter or drive portion of the disk. Once this is accomplished, off-line
diagnostics and documentation aids are used to troubleshoot the adapter to the defective Field Replaceable Unit (FR U). These same aids, with the addition of the off-line tester, are used to troubleshoot the drive.
The preferred repair philosophy is to replace the defective FRU in accordance with the RM02/03
Service Manual instructions. The Authorized Returns List (ARL) will identify those FRUs to be
returned.
NOTE
Procedures requiring special training (head cleaning,
carriage, and rail alignment) should not be attempted
by untrained personnel.
1.2

RESOURCES

1.2.1 Related Documentation
A list of all RM02 and RM03 related documentation that exists on hard copy or microfiche is provided
in Table 1-1.

1-1

Table 1-1

RM02/03 Documentation

RM02 Disk Drive Technical Manual - Volume I

(EK-I RM02-TM)*

RM02 Disk Drive Technical Manual - Volume II (RM02 Print Set)

(EK-2RM02-TM)

RM03 Disk Drive Technical Manual - Volume I

(EK-I RM03-TM)*

RM03 Disk Drive Technical Manual - Volume II (RM03 Print Set)

(EK-2RM03-TM)

RM02/03 Disk Subsystem User's Guide

(EK-RM03-UG)

RM02/03 Adapter Technical Description Manual

(EK-RM023-TD)*

RM02 Disk Subsystem Illustrated Parts Breakdown

(EK-RM 02-IP) *

RM03 Disk Subsystem Illustrated Parts Breakdown

(EK-RM03-IP)*

RM02 Field Maintenance Customer Print Set (Adapter Print Set)

(MP-00456)

RM03 Field Maintenance Customer Print Set (Adapter Print Set)

(MP-00350)

*These documents are also available on microfiche. Order as EP-XXXXX-XX.

1.2.2 Special Tools
To maintain the RM02/03 Disk Drive, the following special tools will be needed by field service
personnel.
Part No.

Part

29-13212
29-22933
29-22934
29-22935
29-22936
29-22914
30-13992-02
RM03-P
RM03-FTU

Torque Screwdriver
Card Extender
Spindle Alignment Tool
Head Adjustment Tool
Bit Head Adjust
Speed Sensor Tool
CEPack
Data Pack
Off Line Tester

It is also recommended that a 10 inch standard screwdriver and a 10 inch Phillips head screwdriver be
available. The first will be needed to adjust drive belt tension. The second will be necessary to remove
the front bezel bracket in order to replace the absolute filter.

1.2.3 Initial Spares
The following parts comprise the RM02/03 branch kit.

1-2

RM02 DEC/CDC Cross Reference (Part Numbers)
Description

DEC Part No.

CDC Part No.

Fuse, 2 A 250 V
Fuse, 8 A 250 V
Magnet assembly
HR VV receiver (A2B02)
ASGV speed detect (A2AIO)
BSHV power supply (AI A03)
5SJV power supply (AIAOl)
5SKV power supply (AIAOl)
JTVV transmitter (A2801)
JFRV fine servo (A2A03)
EKFV fault register (A2A04)
FLPV servo control (A2A09)
JLQV D / A converter (A2A07)
LLR V data latch (A2A05)
BLSV write PLO (A2AO I)
NLTV A-Cont/Sect (A2B08)
ELUV A-Cont 2 (A2A08)
ML VV A-Cont 1 (A2B09)
FL WV diff generator (A2B06)
ELXV NRZ to MFM (A2B07)
CLZV read PLO (A2A06)
Meter, hour 60 Hz
FZQN servo preamp (A3A05)
Head and arm assembly (Lower)
Head and arm assembly (Upper)
Head and arm assembly (Serov)
NZJN head select/read amp (A3A02)
DZKN write drive (A3A03)
Spindle assembly
Blower assembly, 60 Hz
Blower assembly, 50 Hz
Brake assembly hysteresis
HZYN Control panel assembly (A3AOl)
Flex lead assembly
Transducer assem bly
Transformer, 60 Hz
Transformer, 50 Hz
Sensor assembly, speed
Carriage and coil assembly
Motor, drive 60 Hz
Motor, drive 50 Hz
5VTN Servo power (A3A04)
Tool sensor height adjust
Belt, drive 60 Hz
Belt, drive, 50 Hz

29-22872
29-22873
29-22874
29-22875
29-23117
29-22877
29-22878
29-22879
29-22880
29-23112
29-22882
29-22883
29-22884
29-23113

95647602
95647606
47200700
54147709
54152505
54152902
54153300
54153700
54167710
54226114
54262105
54275307
54275710
54276113
54276502
54276914
54277306
54277713
54278107
54278505
54279304
73120400
73485311
75010302
75010303
75010305
75061719
75062106
75074714
75240304
75240305
75241500
76422501
76426800
76427300
76840400
76846800
77387101
77398303
77398414
77398412
77569100
87052600
92314099
92314115

29~23111

29-23116
29-22888
29-22889
29-22890
29-23115
29-23114
29-22893
29-22894
29-23109
29-23107
29-23108
29-23119
29-23118
29-22900
29-22901
29-22902
29-22903
29-22904
29-22905
29-22906
29-22907
29-22908
29-22909
29-22910
29-23121
29-23122
29-22913
29-22914
29-23110
29-23120

1-3

RM02 DEC/CDC Cross Reference (Part Numbers) (Cont)
Description

DEC Part No.

CDC Part No.

Circuit breaker, 5 A 60 Hz
Circuit breaker, 5 A 50 Hz
Switch interlock
Switch, mini
Circuit breaker, 8 A 50 Hz
Circuit breaker, 5 A 60 Hz
243-29MFD 60 Hz
Meter, hour 50 Hz
Filter, air 15.77 X 11
Filter, air
4MFD 370 Vac 10%
Filter, line 10 A
Switch solid state AC
21oo0MFD 50 Vdc and 10
Card extender
Carr /spindle adj tool
Head adj tool
Bit 1/4 Hex hd adj
6MFD 660 Vac 6
Rail, lower carr guide
Rail, upper carr guide

29-22917
29-22918
29-22919
29-22920
29-22921
29-22922

92696065
92696079
93560002
93786005
94245205
94245217
94255112
94313807
94364700
00815481
94365800
94371200
76427404
95578111
54109701
75018400
75018804
87016701
95686701
75063600
75063700

N/A
29-22924
29-22925
29-22926
29-22927
29-22928
29-22929
29-22930
29-22933
29-22934
29-22935
29-22936
29-22938
29-23028
29-23029

RM03 DEC/CDC Cross Reference (Part Numbers)
Description

DEC Part No.

CDC Part No.

Fuse, 2 A 250 V
Fuse, 8 A 250 V
Magnet assembly
HR VV receiver (A2B02)
ASGV speed detect (A2AI0)
BSHV power supply (AIA03)
5SJV power supply (AIAOl)
5SKV power supply (AIAOl)
JTVV transmitter (A2801)
HFR V fine servo (A2A03)
EKFV fault register (A2A04)
FLPV servo control (A2A09)
JLQV D / A converter (A2A07)
HLRV data latch (A2A05)
CLSV write PLO (A2AOl)
EL TV A-Cont/Sect (A2B08)
EL UV A-Cont 2 (A2A08)
MLVV A-Cont 1 (A2B09)
FL WV diff generator (A2B06)

29-22872
29-22873
29-22874
29-22875
29-22876
29-22877
29-22878
29-22879
29-22880
29-23881
29-22882
29-22883
29-22884
29-22885
29-22886
29-22887
29-22888
29-22889
29-22890

95647602
95647606
47200700
54147709
54152505
54152902
54153300
54153700
54167710
54226113
54262105
54275307
54275710
54276108
54276503
54276909
54277306
54277713
54278107

1-4

RM03 DEC/CDC Cross Reference (Part Numbers) (Cont)
Description

DEC Part No.

CDC Part No.

ELXV NRZ to MFM (A2B07)
BLZV read PLO (A2A06)
Meter, hour 60 Hz
FZQN servo preamp (A3A05)
Head and arm assembly (Lower)
Head and arm assembly (Upper)
Head and arm assembly (Servo)
N ZJN head select/read amp (A3A02)
EZKN write drive (A3A03)
Spindle assembly
Blower assembly, 60 Hz
Blower assembly, 50 Hz
Brake assembly hysteresis
HZYN Control panel assembly (A3AO 1)
Flex lead assembly
Transducer assembly
Transformer. 60 Hz
Transformer, 50 Hz
Sensor assem bly, speed
Carriage and coil assembly
Motor, drive 60 Hz
Motor, drive 50 Hz
5VTN Servo power (A3A04)
Tool sensor height adjust
Belt, drive 60 Hz
Belt, drive, 50 Hz
Circuit breaker, 5 A 60 Hz
Circuit breaker, 5 A 50 Hz
Switch interlock
Switch, mini
Circuit breaker, 8 A 50 Hz
Circuit breaker, 5 A 60 Hz
243-29MFD 60 Hz
Meter, hour 50 Hz
Filter, air 15.77 X 11
Filter, air
4MFD 370 Vac 10%
Filter, line 10 A
Switch solid state ac
21000MFD 50 Vdc and 10
Card extender
Carr /spindle adj tool
Head adj tool
Bit 1/4 Hex hd adj
6MFD 660 Vac 6
Rail, lower carr guide
Rail, upper carr guide

29-22891
29-22892
29-22893
29-22894
29-22895
29-22896
29-22897
29-22898
29-22899
29-22900
29-22901
29-22902
29-22903
29-22904
29-22905
29-22906
29-22907
29-22908
29-22909
29-22910
29-22911
29-22912
29-22913
29-22914
29-22915
29-22916
29-22917
29-22918
29-22919
29-22920
29-22921
29-22922
29-22923
29-22924
29-22925
29-22926
29-22927
29-22928
29-22929
29-22930
29-22933
29-22934
29-22935
29-22936
29-22938
29-23028
29-23029

54278505
54279303
73120400
73485311
75010102
75010103
75010105
75061715
75062107
75074714
75240304
75240305
75241500
76422501
76426800
76427300
76840400
76846800
77387101
77398303
77398410
77398413
77569100
87052600
92314113
92314119
92696065
92696079
93560002
93786005
94245205
94245217
94255116
94313807
94364700
00815481
94365800
94371200
76427404
95578111
54109701
75018400
75018804
87016701
95686701
75063600
75063700

1-5

The following parts comprise the DEC portion of the RM02/03 branch kit. These parts are to be
contained in a standard universal case, 29-22390, which will be distributed with the parts. A special
insert has been designed for it, 29-23001.
DEC Part No.

Description

Quantity

M5922
M5923
M7684
M7685
M7686
M7687
54-11086
70-13784

Transceiver
Transceiver
Control Sequencer
Data Sequencer
Control Interface
Drive Data Interface
15 V Regulator
H7440 Assembly

1
1
1
1
1
1
1
1

Parts which will not fit in either case, but are nevertheless part of the kit are as follows.
DEC Part No.

Description

Quantity

29-22901
or
29-22902

Blower Assembly, 60 Hz 1
Blower Assembly, 50 Hz

29-22904

Control Panel Sw. Assy.

29-22906

Transducer Assembly

29-22911
or
29-22912

Drive Motor, 60 Hz

29-22925

Filter

29-22926

Filter

30-13992-02

CE Pack

RM03-P

Data Pack

Drive Motor, 50 Hz

1.2.4 Cable List
The following is a list of cables and DEC part numbers.
Name

Number

Controller I/O Cables (Three in controller)
25 ft Massbus Cable (Controller to drive)
15 ft Massbus Cable (Drive to drive)
Power Sequence Cable (Drive to drive)
Power Sequence Jumper (18 on adapter backplane)
Ground Strap (Drive to drive)
Ground Strap (Controller to drive)
Terminator Assembly (On last drive)

BC06R-8
BC06S-25
BC06S-15
7009491-02
7009490
7412827-3
7412827-25
7009938-00

1-6

1.2 .5 Diagnostics
The diagnostic tests that are used during installation of the disk subsystem may be used any time to
demonstrate system performance or to help pinpoint problem areas. A brief functional description of
these programs is provided.
RM02/03 Drive Diagnostics
RM02/03 Formatter (MAINDEC-ZZ-CZRMA) - This program provides the facilities to format or
check the header and data fields of each data block on the disk pack.
In the format operation, the program writes the header of each data block with a cylinder number,
track number, and sector number. It also writes the data field with a selected data pattern. The program then verifies the written data blocks by executing the Write Check Head and Data command.
In the check operation, the program repeats the format operation three times while the data pattern is
rotated one bit at each pass.
The formatter will also flag bad sectors, and allows access to the bad sector file.
RM02/03 Performance Exerciser (MAINDEC-ZZ-CZRMB) - This program performs an interactive
test on RM02/03 Disk Drive connected to a Massbus system. It is used to verify that the drives under
test are performing to their data error rate.
The program will exercise a mixed system of dual port and single port drives and monitor the performance of each. It reports the statistics for each drive being exercised either on request from the operator
or automatically at intervals determined by the operator.
RM02/03 Functional Tests - The functional test is a stand alone program which uses functional means
to verify the operability of the RM02/03 disk subsystem. The Functional Test is comprised of three
parts, which would normally be run in sequence starting with part I. Briefly, part I tests housekeeping
and mechanical positional operations; part II tests write, read and write check operations using header
and data; part III tests write, read and write check operations using data.
Part I (MAINDEC-ZZ-CZRMC) - Part I is used to establish confidence in the basic operations of the
disk drive, including mechanical positioning and data transfer operations.
Part II (MAINDEC-ZZ-CZRMD) - Part II of the Functional Test performs write, read and write
check operations using header and data.
Note that part II of the Functional Test leaves two header errors on the media and the pack must be
reformatted after running this test.
Part III (MAINDEC-ZZ-CZRME) - Part III of the Functional Test performs write, read and write
check operations using data.
Note that part III of the Functional Test leaves two header errors on the media and the pack must be
reformatted after running this test.
NOTE
Although the Functional Test, Parts II and III,
leaves header errors on the pack, the Revision B or
higher versions will correct the errors. REV A of the
Functional Test requires reformatting after each use.

1-7

RM02/03 Extended Drive Test (MAINDEC-ZZ-CZRMF) - This program contains a series of tests
that will verify that the disk drive is capable of performing seeks and that the access times are within
tolerance. It also verifies that the track and sector addressing circuitry operates properly and that the
data storage and retrieval capabilities are functioning.
RM02/03 Dual Port Logic Test, Part I (MAINDEC-ZZ-CZRMG) - This program performs tests on
the dual port control logic. During this test both ports of the drive are cabled to the same Massbus by a
special adapter cable. This arrangement allows the dual port logic to be tested from a single RH
controller.
RM02/03 Dual Port Logic Test, Part II (MAINDEC-ZZ-CZRMH) - Part II of the Dual Port Logic
program is used to test the Port Select Switch. The special cable is also used during this test to permit
operation from a single RH controller.
RM02/03 Drive Compatibility Test (MAINDEC-ZZ-CZRMI) - This program is used to verify the
compatibility of up to 16 drives which may reside on one or more RH controllers. It tests the ability of
a drive to write data that can be successfully read by all other drives, and to overwrite data written by
all other drives. The diagnostic will detect the following causes of incompatibility:
1.
2.
3.
4.
5.

Head misalignment
Positioner lateral misalignment
Spindle runout
Improper levels of write current
Incorrect addressing of read/write heads.

RM02/03 Diskless Diagnostic (MAINDEC-ZZ-CZRMJ) - This standalone program is used to verify
the operability of the RM02/03 Disk Subsystem independently of the disk drive. It is used to resolve
hardware failures in the RM02/03 Adapter to field replaceable modules.
1.3 PREVENTIVE MAINTENANCE
This section provides a general outline of the Preventive Maintenance Procedure to be used on the
RM02/03 Disk Drive. For more specific information, refer to the Site Management Guide.
Procedure

Frequency

General Cleaning
Replace Primary Filter
Replace Absolute Filter
Clean Shroud and Spindle
Clean and Lubricate Lockshaft
Inspect and Clean Rails and bearings
Check Power Supply Output
Check Head Alignment

Quarterly
Quarterly
Annually
Quarterly
Quarterly
Quarterly
Quarterly
Semi-Annually

1-8

CHAPTER 2
INSTALLATION

2.1 INTRODUCTION
.
This chapter details the information required to install an RM02 or an RM03 Disk Subsystem. There
is a variety of possible combinations of drives, controllers, and processors, and Table 2-1 lists the
currently acceptable configurations.

Table 2-1

Subsystem Configurations

Drive

Controller

Processor

RM02

RHII

PDP-II (excludmg PDP-Il/70)

RM02/RPxx

RHII

PDP-II (excluding PDP-II /70)

RM03

RH70

PDP-I 1/70

RM03/RPxx
mix

RH70

PDP-II/70

mIx

Any special information regarding the drive or drive mix will be detailed in the paragraphs describing
the specific controller's installation.
2.2 SITE PREPARATION AND PLANNING
This paragraph describes power, space. environmental, cable length, and safety requirements that
must be considered before installation of the RM02 or RM03 Disk Subsystem.
2.2.1 Environmental Considerations
The RM02 and RM03 Disk Subsystems are designed to operate in a business or light industry environment. Although cleanliness is an important consideration in the installation of any computer system, it
is particularly crucial for proper operation of a disk drive. The RM03P disk cartridge is not sealed
while being loaded and is therefore vulnerable to dust or smoke particles, fingerprint smudges, hair,
lint, etc. These minute obstructions can cause head crashes, resulting in catastrophic damage to the
read/write heads and disk surfaces.
2.2.1.1 Cleanliness - The drive can operate in an ambient of less than one million particles (0.5
micron or larger in diameter) per cubic foot of air. The drive contains a filter system which, under these
conditions, maintains the particle count within the cartridge below 100 particles per cubic foot.

2-1

2.2.1.2 Space Requirements - The space requirements for each drive is shown in Figure 2-1. The
drives may be arranged so that they are either immediately adjacent to each other, or separated by a
distance of up to 61 cm (2 ft) maximum. If the drives are arranged so that they are immediately adjacent
to each other. they will have to be pulled out of line to perform some types of service.

- - - --,

SERVICE
AREA

OPTIONAL CABLES
BC06S-25
BC06S-40

25 FOOT CABLE
40 FOOT CABLE

DRIVE

PDP-11/70

* 2 FT MAX

13-1/2 FT MAX

RH70

I
I C
I
I

25 FT CABLE

15 FT CABLE

I
I

I
I
I

DIMENSIONS

HEIGHT

INCHES

21-5/8

CENTIMETERS

91.4

83.8

91.4

54.9

99.1

SERVICE
AREA

I
I
I
I

- --- ~

* WITH STANDARD CABLE LENGTH
MA-0644

Figure 2-1

Disk Subsystem Space Requirements

2-2

The maximum subsystem Massbus cable length is 48.77 m (160 ft). To calculate drive location, assume
each drive uses 4 m (13 ft) of Massbus cable within the drive [2 m (6 1/2 ft) in and 2 m (6 1/2 ft) out].
Allow 1.5 m (5 ft) of cable for the connection to the RH controller inside its cabinet. Hence, the first
drive may be located up to 4.1 m (13 1/2 ft) from the controller as shown in Figure 2-1.
When calculating the total cable length, add an extra 0.5 m (1-1/2 ft) for each MBA backplane.
2.2.1.3 Floor Loading - The weight of the disk drive alone (196 kg/430 lb) will not place undue stress
on most office-building, industrial-plant, or raised-computer-room floors. However, the added weight
of the number of cabinets and drives should be considered in relation to the weight of existing computer systems plus needs for possible future expansion.
2.2.1.4 Heat Dissipation - The heat dissipation of some RM02 or RM03 Disk Subsystems may reach
2500 Btu/hour, maximum. The approximate cooling requirements for the entire system can be calculated by mUltiplying this figure by the number of drives, adding the result to the total heat dissipation
of the other system components, and then adjusting the total figure to compensate for personnel,
cooling system efficiency, etc. It is advisable to allow a safety margin of at least 25 percent above the
maximum estimated requirements.
2.2.1.5 Acoustics - Most computer sites require at least some degree of acoustical treatment. However, the disk subsystem should not contribute unduly to the overall system noise level. Ensure that the
acoustical materials used do not produce 0r harbor dust.
2.2.1.6 Temperature - The operating temperature range of the RM02 or RM03 Disk Subsystem is
from 15° C (59° F) to 32° C (90° F). The maximum temperature gradient is 7° C (12° F) per hour. The
non-operating temperature range is from -40° C (-40° F) to 66° C (151 ° F) with a maximum gradient
of 20° C (36° F) per hour.
2.2.1.7 Relative Humidity - Humidity control is important for proper operation of any computer
system since static electricity can cause memory errors as well as permanent damage to logic components. The RM02 and RM03 Disk Subsystems are designed to operate within a relative humidity
range of 20 to 80 percent with a maximum wet bulb temperature of 28° C (82° F) an a minimum dew
point of 2° C (36° F). The non-operating relative humidity range is from 5 to 95 percent, with a
maximum wet bulb temperature of 46° C (115° F).
2.2.1.8 Altitude - Computer system operation at high altitudes can result in heat dissipation problems. Altitude also affects the flying height of heads in disk drives. The maximum altitude specified for
operating the RM02 or RM03 Disk Subsystem is 2000 m (6500 ft). However, the maximum allowable
operating temperature is red~ced by a factor of 1.8° C/IOOO m (10 F /1000 ft) for high-altitude sites.
Thus, the maximum allowable operating temperature at 2000 m (6500 ft) would be reduced to 28° C
(83.5° F).
2.2.1.9 Attitude/Mechanical Shock - Performance of the RM02 or RM03 Disk Subsystem will not be
affected by an attitude where maximum pitch and roll do not exceed ± 5 degrees.
The subsystem is designed to operate while a half-sine shock pulse of 2 G peak and 10 ms maximum
duration is applied once in either direction of three octagonal axes (3 pulses total).
2.2.1.10 Power and Safety Precautions - The RM02 or RM03 Disk Subsystem presents no unusual
additional fire or safety hazards to an existing computer system. AC power wiring should be carefully
checked, however, to ensure that its capacity is adequate for the added load and for any contemplated
expansion. The disk subsystem is UL-listed and CSA-certified.

2-3

2.2.2 AC Power Wiring
DEC power wiring conforms to UL, CSA, and VDE standards. This means that the wire used as
equipment ground is green and yellow. It carries no load current (except in emergency), but does carry
leakage current. No equipment is permitted to leave DEC that does not have a grounding connection
to its frame.
The ac return line (also called the "identified" conductor, neutral, common, cold lead, etc.) is blue. It
must not be used to ground equipment. Its purpose is to conduct current.
The ac input line (hot wire) is brown. Its purpose is to supply current to the system. The ac plugs and
receptacles used on this subsystem are shown in Figure 2-2.

PLUG

SOURCE

RECEPTACLE

120V
15 A
1-PHASE

#5262
5-15R
12-05351

NEMA #5-15P
DEC #90-08938

240V
15 A
1-PHASE
NEMA #6-15P
DEC #90-08853

6-15R
12-11204

USED ON
ALL 120 V TABLE-TOP
COMPUTERS.
STANDARD
120 V LOW-CURRENT
DISTRIBUTION. 120 V
TU10 UNITS. MOST
120 V TERMINAL
DEVICES.

ALL 240 V TABLE-TOP
COMPUTERS.
STANDARD
LOW-CURRENT 240 V
DISTRIBUTION.
·MOST240V
TERMINAL DEVICES.
240 V TU1 O.

MA-0913

Figure 2-2

Approved Electrical Plugs and Receptacles

2.3 DRIVE UNPACKING AND INSPECTION PROCEDURE
When delivered, the drive and its associated cabinetry are enclosed by a heavy cardboard carton and
are attached to a shipping skid (Figure 2-3).
1.

I nspect the outside of the container for damage. Then remove the plastic straps that secure
the shipping carton to the skid.

Remove the disk pack box.

Remove the lid from the top of the disk drive carton.

2-4

DISK PACK

5-PANEL FOLDER

(9905975)

CRATING SLAT

(7606858)

CUSHIONED
SHIPPING SKID

MA-0914A

Figure 2-3

Shipping Package

Remove the staples that fasten the wooden crating slats and carton flanges to the skid.

Remove the shipping carton.

Inspect the cabinet and drive for physical signs of shipping damage. Retain all packing
material and receipts in the event that any claims are filed for shipping damage. All damage
claims should be filed promptly with the transportation company.
Digital Equipment Corporation should be notified immediately if a damage claim is made<

Inventory all hardware, cables, manuals, etc. in the shipping carton against the packing slip.
Notify Digital Equipment Corporation immediately if any discrepencies exist.

Remove front door assembly (Figure 2-4).

2-5

PULL DOWN ON
SPRING LOADED
ROD TO REMOVE
FRONT DOOR
THEN LIFT OFF
BOTTOM PIN

LIFT

MA-0649

Figure 2-4

Front Door Removal

Remove orange angle brackets (Figure 2-5) which attach MBA drawer assembly to cabinet
frame.
CAUTION
Do not misplace these brackets. They must be replaced before the installation is completed.

10. Remove the rear cover assembly (Figure 2-6).
II. Slide the MBA drawer forward and remove the sheet-metal screws that attach the side
panels (Figure 2-7) to the cabinet frame.
12. Slide the MBA drawer back into position.
13. Lift off the side panels.
14. Remove the two bolts securing the cabinet to the shipping skid.
15. Remove all skid blocks and position the cabinet leveling feet so that the cabinet rolls freely
on its casters.
16. Carefully lower the cabinet off the skid without jarring the cabinet.

2-6

FRONT
BEZEL

BEZEL SCREWS
~

IIO.O~
~
o0 0
c::::::I

" •

Iff

ADAPTER

:t...

J
.J

ANG_LE
BRACKETS
MA-0650

Figure 2-5

Front Bezel Location

B~~--------------i~B
~- -

-----6-

TO REMOVE REAR COVER:
1. LOOSEN LOCKING SCREWS (A).
2. LIFT REAR COVER OFF PINS (B).
MA-0651

Figure 2-6

Rear Cover Removal
2-7

TO REMOVE SIDE PANELS
REMOVE SCREWS AT LOCATIONS (A)
AND LIFT PANEL UP. FREE PINS (B).
THEN PULL OUTWARDS.
MA-0646

Figure 2-7

Side Panel Mounting Screws

17.

Roll the cabinet to the area designated by the site preparation plan.

18.

Extend the MBA slide forward. Loosen the screws on the MBA logic cage assembly and
remove the cover.

19.

Ensure that all MBA boards and cable connections are firmly seated.

20.

Replace cage cover.

2-8

21.

Loosen the two quarter-turn fasteners at the rear of the drive and then slide the rear cover
back and lift it off.

22.

Verify that all logic cards are firmly seated in the drive logic chassis and power supply.

23.

Verify that all drive connectors are firmly seated.

24.

Remove the two screws that secure the front bezel (Figure 2-5). Lift the front bezel up and
off.

25.

Insert a screwdriver blade into the slot under the pack access cover latch and depress the
pack access cover latch release.
NOTE
The pack access cover latch is not functional unless
ac power is applied to the drive.

26.

Raise the pack access cover.

27.

Remove the plastic cover from the spmdle.

28.

Remove the two deck hold-down screws (Figure 2-8).

29.

Locate the drive shipping bracket which is located on the right side of the drive baseplate
(Figure 2-8). Loosen the upper bolt. Remove the lower shipping bracket bolt. Swing shipping bracket 180 degrees and tighten upper bolt. Replace lower shipping bracket bolt.
CAUTION
Do not remove or misplace the shipping bracket. It
must be used any time the drive is moved.

30.

Raise the drive deck and verify that all cabling is intact and that there are no broken or
damaged wires.

31.

Lower the drive deck and replace the two hold-down screws.

32.

Remove the actuator holding pin from the hole labeled "Shipping Lock" and place it into
the hole labeled "Pin Storage." The actuator holding pin is located on the rail bracket above
the carriage coil assembly (Figure 2-9).

33.

Remove the rear deck hold-down screw and spacer (Figure 2-10). Using the hold-down
screw, fasten the spacer onto the actuator magnet housing via the keeper hole.

CAUTION
The spacer must be placed between the magnet housing and the baseplate any time the drive deck is
raised in order to prevent damage to the rubber shock
mounts.

2-9

KEEPER HOLE

DECK
HOLDDOWN.
SCREWS

SHIPPING)
DECK
BRACKET
CASTING ( MOUNTS
HERE

SHOCK

taP.4!.--~~-:-- MOUNT

MA-0611

Figure 2-8

Deck Maintenance Position
2-10

SHIPPING
LOCK
PIN
STORAGE

ACTUATOR
HOLDING
PIN

MA-0607

Figure 2-9

Location of Actuator Holding Pin

2-11

KEEPER HOLE

I
I

l
~

()

SPACER/

MA-0609

Figure 2-10

2.4

Location of Rear Deck Holding Screw

RHll CONTROLLER INFORMATION

The following paragraphs describe the mechanical and electrical installation, power checks, jumper
configurations, and visual inspections necessary for installation of the R H 11 con roller . The R H 11
con roller will handle an RM02/RPxx drive mi~. The particular details required to accommodate the
mix are described in the individual paragraphs on jumper configurations.

2.4.1 Mechanical
The RHII uses two hex-height modules and must be installed in a mounting box that accommodates
hex-height modules. The modules are inserted in a double-system unit backplane which is installed in
the mounting box with four thumbscrews. The double-system unit is oriented with the bus cable slots
in line with the other options. Figure 2-11 shows a module utilization chart.

2-12

I
UNIBUS
AIN
(BUSA)
(SEE NOTE 1)

UNIBUS
B
OUT
(BUSB)
(SEE NOTE 2)

UNIBUS
B
IN
(BUSB)
(SEE NOTE 2)

UNIBUS
A
OUT
BUSA)
(SEE NOT(3)

G727

M7297

PARITY
CONTROL
(PAC)

BUS
CONTROL
(BCT)
MODULE

DATA
BUFFER

&
CONTROL
(DBC)
MODULE

MASSBUS
TRANSCEIVER
(MBSA)

MASSBUS
TRANSCEIVER
(MBSB)

MASSBUS
TRANSCEIVER
(MBSC)

M7296

E
CONTROL

UNIBUS
POWER
FAil
DRIVER
(BUSB)

UNIBUS
POWER
FAil
DRIVER
(BUSA)

&
STATUS
REGISTERS
(CSR)
F

NOTES:
1.

MAY BE EITHER M920 (CONNECTION FROM ADJACENT DEVICE) OR
BC11A CABLE (CONNECTION FROM ANOTHER BOX OR NON ADJACENT
DEVICE).

MAY BE M920 (CONNECTION TO ADJACENT DEVICE). M930 (TERMINATION
AT END OF UNIBUS A) OR BCllA CABLE (CONNECTION TO NEXT BOX OR
NON ADJACENT DEVICE).

MAY BE M9300 (TERMINATION AT BEGINNING OR END OF UNIBUS B) OR
BC11A CABLE (CONNECTION TO OTHER BUS B DEVICES).

G727 GRANT CONTINUITY MODUlE(S) MUST BE INSERTED IN SLOTS D
11-2384

Figure 2-11

RHlI Module Utilization
2-13

2.4.2 Electrical
The power cable connections, Unibus cable connections, and Massbus cable connections are described
in the following paragraphs.
2.4.2.1 Power Cable Connections - Power is distributed to the RH 11 modules via two power cables
that attach to the printed circuit backplane assembly by quick-disconnect tabs. (Refer to RH 11 wired
assembly drawing, D-AD-7009397-0-0.) The power cables have Mate-N-Lok connectors on one end,
which connect to the power distribution panel located above the backplane, and quick-disconnect tabs
on the other end, which connect to the printed circuit backplane. The following chart shows the color
codes associated with the power harness connections.
Red
Black
Blue
Gray
Violet
Yellow
Brown

+S Vdc
Gnd
-IS Vdc
+ 15 Vdc
DC LO ( + 3 V to + 5 V)
A C LO ( + 3 V to + S V)
LTC 8 V peak-to-peak ac
CAUTION
When connecting the power cables to the backplane,
ensure that backplane wires are not damaged. Also,
do not cut AC LO and DC LO wires out of the power
harness as they are used for power fail conditions on
the Massbus and on both Unibus A and Unibus B
ports.

After power connections have been made, check for power shorts with an ohmmeter. Ensure that all
modules are firmly seated in the proper slots (Figure 2-11). Power-up the cabinet and measure voltages
in accordance with values listed in the color code chart for power connections. After this is done, turn
power off.
2.4.2.2 Unibus Cable Connections - The RHII is a 2-port Unibus device capable of accepting two
Unibus cable systems, designated Unibus A and Unibus B.
Unibus A Connections - The Unibus A cable slots connect the RHII to the processor controlling it.
The Unibus A cable enters the RHII via slot AI, BI and connects to the next device via slot A9,
B9.(Refer to module utilization drawing, D-MU-RHll-O-Ol.)
Connections to slot AI, BI are made via the BCII A Unibus cable if the RH 11 is the first Unibus A
device in the mounting box. Otherwise, connection to AI, BI from the preceding device is made by an
M920 Unibus jumper module. Connection to the next adjacent device on the Unibus is made via the
M920 Unibus jumper module; it is made by a BCIIA cable if the device is not adjacent.
NOTE
If the RUII is the last device on Unibus A, an M930
terminator module is installed in slot A9, B9.

2-14

UnibusB Connections - Unibus B connections are generally made in systems with multiport memories.
When the Unibus B port of the RH 11 is not used, an M9300 terminator module (with jumper \Vl cut)
should be installed in slot A8, B8 to terminate Unibus B signals into the RH 11. The second M9300
terminator module should not be used in order to conserve power. If the Unibus B port of the RHII is
used, connections are determined on the basis of whether a processor is connected to Unibus B. These
connections are described below.
I.

Processor on Unibus B - If a processor is connected to Unibus B, it is electrically connected
at the beginning of the bus. In this case, the M930 terminator modules supplied with the
processor are used for bus termination, and the two M9300 Unibus B terminator modules
supplied with the RH 11 are not used.
NOTE
The M9300 terminator may be used as a substitute
for the M930 terminator if the jumpers are selected
correctly.
The Unibus B cable connection to the RH 11 is made via slot A8, B8 with a BCIIA cable.
Connection from the RH 11 to the next device is made via a BCII A cable connected to slot
A 7. B7. If the RH 11 is the last device on the bus, the M930 or M9300 terminator is installed
in slot A 7, B7 instead of the Be 11 A cable.

No Processor on Unibus B - If no processor is connected to Unibus B, a M9300 Unibus B
terminator module must be selected as an NPR arbitrator. If one RH 11 is connected to
Unibus B, the RHII is electrically connected at the beginning of the bus with the M9300
selected to act as an NPR arbitrator. One M9300 Unibus B terminator module is placed in
slot A8, B8 of the RHII. Jumper WI on this module must be cut to enable the arbitration
logic. Connection to other devices on Unibus B, such as memory, is made via a BCIIA cable
connected to slot A 7, B7. The second M9300 Unibus B terminator module is installed in the
last device on Unibus B. Jumper W2 is removed for terminating the Unibus with no processor connected.
NOTE
In this case, an M930 terminator module can be substituted for the M9300 Unibus B terminator in the
last device slot. If more than one RH 11 is installed,
the user may have extra M9300 modules as a result
of a particular configuration. Figures 2-12,2-13. and
2-14 show typical Unibus configurations.

2.4.2.3 Massbus Cables - Massbus connections to the RHII are made via three 40-conductor ribbon
cables. These cables plug into three M5904 transceivers in the RH II and are designated Massbus
Cable A, Massbus Cable B, and Massbus Cable C. The connections are made as shown below.
Massbus Cable A
M assbus Cable B
Massbus Cable C

Install in M5904 mod~.;le in s]ot C4. D4.
Install in M5904 module in slot C5, D5.
Install in M5904 module 10 slot C6, D6.

2-15

RH 11

UNIA
IN

UNIB
OUT

AB01

AB07

MEMORY

PDP-11

E
M
p

M930

UNIA
OUT

UNIA
IN

T
Y

UNIA
OUT

UNIB
IN

M9300
TERM
MODULE
(ABOB)

UNIA
OUT

AB09

W1-0UT
W2-IN
W3-IN
SEE
NOTE 1

BEGINNIN~

UNIBUS A

UNIBUSA

NOTE:
INSTALL M930 TERMINATOR IF LAST DEVICE ON UNIBUS A

UNIBUS A

TO
END OF
UNIBUS
A

11-2220

Figure 2-12

Single-Port Unibus Configuration

2-16

UNIBUS B

END
UNIBUS
B

M9300
W1-IN
W2-0UT
W3-IN

RH11

BEGINNING
UNIBUS
B

UNIA
IN
UNIB
IN

UNIB
OUT

AB01

AB07

SOLID STATE MEMORY

PDP-11/45

M9300
AB08

AB09

MEMORY

M930

UNIA
IN

UNIA
OUT

W1-0UT
W2-IN
W3-IN

UNIA
OUT

UNIB
OUT

f
BEGINNING
UNIBUS A

UNIA
OUT

SEE
NOTE 1

UNIB
IN

J
UNIBUS A

TO
END OF
UNIBUS
A

UNIBUS A

NOTE:
INSTALL M930 TERMINATOR IF LAST DEVICE ON UNIBUS A

11-2221

Figure 2-13 Dual-Port Configuration Memory on Unibus B

2-17

MEMORY

PDP-11
M930

UNIB
OUT

UNIB
IN

D
BEGINNING
UNIBUS B

UNIBUS B

UNIB
UNIB
IN
OUT
BUS WINDOW
UNIA
UNIA
OUT
IN

UNIBUS B

RH11
UNIA
IN

END
UNIBUS
B

UNIA
OUT

M9300
TERM
MODULE

AB01
PDP-11

M930

MEMORY

D
BEGINNING
UNIBUS A

UNIA
OUT

UNIA
IN

UNIA
OUT

W1-IN
W2-0UT
W3-0UT

AB08

AB09

SEE
NOTE 2

SEE
NOTE 1
UNIB
IN

UNIB
OUT
;

.UNIBUS A

UNIBUS A

NOTES
1.

IN THIS CONFIGURATION CAN BE REPLACED BY M930.

INSTALL M930 TERMINATOR IF LAST DEVICE ON UNIBUS A.

TO
EN o OF
UNI BUS
A

11-2222

Figure 2-14

Dual-Port Configuration - Memory and Processor on Unibus B

2-18

The Massbus cables are marked and should be inserted per the individual cable markings. To terminate the Massbus, a 7009938 terminator pack assembly should be plugged into the output connector(s)
of the last drive (Figure 2-15).

LAST DRIVE
ON MASSBUS

DISK DRIVE

RH 11

M5904
SLOT
CD04

r--..

M5904
SLOT
CD05

M5904
SLOT
CD06

DRIVE

II
-

MASSBUS
ADAPTER
~
~

f---

MASSBUS
ADAPTER
t--r---

r---'

TERMINATOR
PACK ASSY
(7009938)

MASSBUS
CABLE
CONNECTORS
NOTES:

FLAT MASSBUS CABLE (3) INTERNAL TO DRIVE CABINET
AND TO CABINET CONTAINING RH11.

ROUND MASSBUS CABLE EXTERNAL TO CABINETS

LAST DRIVE TERMINATED WITH 7009938
TERMINATOR PACK ASSY.
11-2561

Figure 2-15

Massbus Cable System Configuration

2-19

2.4.2.4 AC LO, DC LO - AC LO and DC LO signals from the RH 11 's power supply must be
connected to the RHl1. The wires supplying these signals will not be cut from the power harness. There
will be only one AC LO and one DC LO power fail connection to each Unibus for devices mounted in the
same mounting box and sharing the same power supply. Otherwise, power fail conditions would latch up
due to positive feedback to the power fail logic. If a power fail connection for AC LO and DC LO is
already made to a Unibus from a device in the same mounting box, the M688 power fail module in the
RH II for that Unibus is removed. The M688 module for Unibus A is located in slot E5 and the M688
module for Unibus B is located in slot E4. The following is a summary of power fail configuration
rules.
1.

For each mounting box, there is only one AC LO and DC LO power fail connection to a
Unibus from the power supply.

Power supply AC LO and DC LO must always be wired to each RH 11 via the power
harness.

Power fail sgnals may only be disconnected from a Unibus in an RH 11 by removing the
appropriae M688 power fail driver module.

Power supply AC LO and DC LO should be disconnected from all other options mounted in
the same box as the RH 1t if they do not need those signals for internal operation.

Figures 2-16, 2-17 and 2-18 show three typical power fail configurations which are configured in
accordance with the above mentioned rules.
2.4.3 Jumper Configurations
The following paragraphs describe the various jumper configurations on the BCT (M7295), DBC
(M7294), and CSR (M7296) modules. The different configurations for RM02 only and for an
RM02/RPxx mix are listed separately within each module subsection.
2.4.3.1 Ber Module (M7295) - The BCT module contains jumpers for register selection, BR level
interrupt, NPR latency, vector address, and missed transfer error.
Register Selection - The RHll is capable of responding to 30 possible Unibus addresses. The number
of address, however, is dependent on the Massbus device. Jumpers Wl-W8 select the block of Unibus
addresses to which the RH 11 /RM02 subsystem responds. The standard block is assigned addresses
77670 through 776746. Table 2-2 shows the addressing scheme.
The jumpers in E3 (D-CS-M7295-0-1, sheet 2) are used to select the appropriate number of registers
for the device. The scheme is to select two less than the appropriate number for the drive. Only the
RM02 subsystems have 22 registers; therefore, select a jumper configuration of 20 (shown in Table 23). The RM02/RPxx mix of drives have 32 registers and require a jumper configuration of 30 (as in
Table 2-4).
BR Level Interrupt - The priority jumper plug for the RH 11 is normally set for the BR5 level. This plug
is located in E57 (D-CS-M7295-0-1, sheet 7).
NRP Latency - Special circuitry is incorporated on the BCT module to improve NPR latency time for
devices connected to the Unibus. This circuitry is enabled via jumper W18 (D-CS-M7295-0-1, sheet 7).
When the jumper is left in, the NPR latency feature is enabled. Not all PDP-II processors work with
this special feature.

2-20

UNIBUS B

UNIBUS A

(

RH11

EXPANDER
MOUNTING
BOX

)

-.J

«
en

«
«
en

III

-.J

0
III

::J

::>

::J

III

()

::J

M688

E04

E05

()

M7295
ABCDEF02
C100
\I

OPTION
A

OPTION
B

NO
POWER FAIL
CONNECTIONS
MADE TO
UNIBUS

NO
POWER FAIL
CONNECTIONS
MADETO
UNIBUS

M7295
ABCDEF02

I
J
I

R37

R38

)

+5V

POWER SUPPLY
AC
LO
~)

DC
LO

SUPPLY AC LO
SUPPLY DC LO
NOTE
ONE RH 11 MOUNTED WITH OTHER OPTIONS IN
AN EXPANDER MOUNTING BOX.
11-2218

Figure 2-16 Typical Fail Configuration
for RH 11 and Options Mounted
in Same Expander Box

2-21

UNIBUS B

i
UNIBUS A
!

F H 11

RH11
0

....J

U
0

....J

U
0

«en

tIl

::l

--'1

....J

tIl

III

tIl

::l

(;J

()

«
«en

tIl

::l

I SEE I
~OTE1 J

r
I
I

)

....J

::l

()

M688
E05

M688
E04

....J

«
«en

::l

....J

::l

SEE
NOTE 1

I
I

M7295
ABCDEF02

ClOD
\l

C84
\1

Cl00

C84

R37

R38

+5V

R37
""""

NO
POWER FAIL
CONNECTIONS
MADE TO
UNIBUS

+5V

)

R38

... -

-1

M7295
ABCDEF02

OPTION
A

EXPANDER
MOUNTING
BOX

+5V

POWER SUPPLY

AC
LO

DC
La

SUPPLY AC LO
SUPPLY DC LO
NOTE 1:
DISCONNECT POWER FAIL SIGNALS FROM BUSA BY REMOVING M68S IN
SLOT E05 B FROM BUSB BY REMOVING M6SS IN SLOT E04
11-2216

Figure 2-17 Typical Power Fail Configuration
for Two RHlls Mounted
in Same Expander Box

2-22

UNIBUS B

UNIBUS A

CPU

RH 11

a...J

gl ~

m
en

en
:::J
m

m
en
m

M.B88
E04

en
:::J
m

:::J

INTERNAL
POWER FAIL
SIGNAL USE

a...J

a...J a...J
Q

PROCESSOR
MOUNTING
BOX

en
m

:::J

-,
SEE
NOTE 1

M7295
ABCDEF02

C100

C84
\L

R37

OPTION
A

--0--'

M7295
ABCDEF 02

NO
POWER FAIL
CONNECTIONS
MADE TO
UNIBUS

POWER SU PPLY

R38

+5V

AC
LO
C)

+5V

DC
LO

SUPPLY AC LO
SUPPLY DC LO
NOTE 1
DISCONNECT POWER FAIL SIGNALS FROM BUSA BY
REMOVING M688 IN SLOT E05.

11-2217

Figure 2-18 Typical Power Fail Configuration
for RH 11 and CPU Mounted
in Processor Box

2-23

Table 2-2

RHll/RM02 Register Address
Jumper Configurations
Jumper In = Binary 0

Address
Bit

17 16
11

Address Bit

Jumper

Jumper Inl
Jumper Out

12
11
10
9
8
7
6
5

WI
W2
W3
W4
W5
W6
W7
W8

Out
Out
Out
In
Out
Out
Out
In

15 14 13 12
1111

11 10 9
8
7
6
5
4
3
2
0
1101110
x
x
x
x
x
\.---y-----I \.---y-----I \.---y-----I ~ ~ ~
7
7
6
7
0 to 3
0 to 7

Table 2-3

RH ll/R M02 Jumper
Configurations

Slot

Jumper

Jumper In/
Jumper Out

1-16
2-15
3-14
4-13
5-12 (2)
6-11 (4)
7-10 (8)
8-9 (16)

Out
Out
In
In
Out
Out
In
Out

Table 2-4 RHII/RM02/RPxx
Mix Jumper Configurations
Slot

Jumper

Jumper In/
Jumper Out

1-16
2-15
3-14
4-13
5-12 (2)
6-11 (4)
7-10 (8)
8-9 (16)

Out
Out
In
In
Out
Out
Out
Out

Bus Grant -If there are no small peripheral controllers installed in slots C7-F7, C8-F8, and C9-F9,
then G727 grant continuity modules must be installed in slot 07, 08, or 09. These modules merely
continue the Bus Grant signals to the next device on the Unibus.
Vector Address Jumpers - The interrupt vector transferred to the processor is jumper-selectable via
jumpers WI1-WI7, representing vector bits 2-8, respectively. The RM02 subsystems are assigned a
vector address of 000254, with the jumper configuration shown in Table 2-5.

2-24

Table 2-5

Interrupt Vector Jumper
Configurations

Jumper

Vector Bits

Jumper In/
Jumper Out*

WI 1
WI2
WI3
WI4
WI5
WI6
WI7

V2
V3
V4
V5
V6
V7
V8

In
In
Out
In
Out
In
Out

• Jumper In = Binary 1.

MXF Jumper - Jumper WI9 (D-CD-M7295-0-I, sheet 9) is used to disable detection of MXF errors
and is used during special maintenance procedures. WI9 is normally left in.
2.4.3.2 DBC Module (M7294) - The DBC module contains jumpers for NPR cycle selection. Unibus
parity, and start counter capacities.
NPR Cycle Selection Jumpers - Two jumpers select the type of cycle to be implemented when performing NPRs. Jumper E66 (3-4) (D-CS-M7294-0-1, sheet 2) selects the RH II to perform one memory reference for each NPR request; this jumper is removed in the RM02 subsystem to allow back-toback memory cycles to occur. Jumper E66 (2-15) takes advantage of dedicated Unibus B systems
(those in which the RH II is used exclusively as a Unibus B master) by allowing the RH II to transfer
complete consecutive blocks of data without giving up the Unibus; to implement this feature, both this
jumper and E66 (3-14) must be cut (BUS HOG mode).
Unibus Parity Jumpers - The RHII option can be selected for 16-data-bit transfers (plus 2 parity bits)
or 18-data-bit transfers. Unibus A and Unibus B can each be selected individually via jumpers WI and
W2 (D-CS-M7294-0-1, sheet 8). If left in, jumper WI allows parity error code detection on Unibus A
when the RHII is performing DATI operations; if WI is removed, the PA and PB parity lines of
Unibus B are used as data bits 16 and 17, respectively. Jumper W2 serves Unibus B in the same manner
as WI serves Unibus A. Both jumpers are normally left in.
Start Counter Jumpers - Various Silo capacities are jumper-selectable before a write operation onto the
disk drive is started. The jumpers selections are listed below (D-CS-M7294-0-1, sheet 9).
Jumper E66, Pins 1-16
Jumper E66, Pins 5-12
Jumper E66, Pins 7-10
No Jumper

Selects full capacity of 64 words
Selects 32 words
Selects 16 words
Selects I word

NOTE
Only the jumper representing the desired Silo capacity should be connected. The other jumpers should be
removed. For RM02 subsystems, the 64-word jumper
E66, pins 1-16) should be connected.

2-25

2.4.3.3 CSR Module (M7296) -The CSR module contains a jumper (W 1 on D-CS-M7296-0-1, sheet
2) to allow for Unibus A selection only. This jumper overrides the ability of the program to select
Unibus B data transfers. The jumper is normally removed.
2.4.3.4

RH 11 Installation Checklist

1. Visually check the RHII backplane assembly for bent pins by sighting along the rows of
pins from two directions. Also check for pinched or broken wires.
2.

Check the backplane for the current wire-wrap revision and remove and check all RH II
modules for current ECO revisions.

Mount for RH 11 backplane assembly in the appropriate mounting box using four 8/32-inch
X I-inch Allen-head screws.

Connect the two power harnesses to the RH 11. Ensure that Mate-N-Lok connectors are
seated firmly in the power distribution panel located on the chassis above the backplane.

5. Check the RH 11 backplane again for bent pins and shorted wires.
6

Power-up the CPU or expander box and check all voltages, then power-down.

Check that the wires supplying AC LO and DC LO signals from the power supply are
connected to the RH II.

Verify and/or select the jumper configurations in the RHII.

Verify that all modules are placed according to the RH 11 module utilization list (D-MURHII-O-I).

10.

Verify that Unibus cable connections are made.

11.

Mount an input/output connector block assembly (7009861) to a connector panel (7412379)
with four 4/40-inch X 5-inch screws (9008042-8).

12.

Verify that two pressure-sensitive labels are applied to the connector panel for each input/output connector block assembly (E-UA-RM02-A-0). Labell is applied above the input/output connector block assembly, and Label 2 is applied below it.

Controller
A B 1 2 3 4
Labell
The second line of Labell must be marked so that only one letter and one number are
visible. The single controller (RH 11) used in an RM02-AA or -AB subsystem, as well as the
first controller used in an RM02-BA or -BB subsystem, is referred to as controller A. If it is
the first subsystem using the connector panel, it is designated controller A I (etc., up to
controller A4). The second controller in an RM02-BA or -BB subsystem is designated as
controller BX, where X is the same subsystem number as the associated controller A.

2-26

Example: Two RH 11 controllers are mounted in the same cabinet, one for each of two
RM02-AA subsystems. Each RH 11 uses one input/output connector block on the connector panel; the first is called controller A 1, the second is A2. Later, an RM02-BA subsystem is installed with its two RH 11 controllers mounted in the same cabinet. The
remaining two slots on the connector panel are used, with one being labeled A3 and the
other B3.
CBA
Label 2
This label simply shows the relative positions of the flat Massbus cables A, B, and C.
13.

Mount the connector panel at the bottom rear of the cabinet containing the R H II, using
four 10/32-inch Tinnerman nuts (Part No. 9(06586) and four 10/32-inch X 0.38-inch Trusshead screws (Part No. 9006071-3). (Refer to D-UA-RM02-A-0).

14. Clean the air filters at the top of the mounting cabinet, if necessary.
15.

Check mounting cabinet fans for proper operation.

2.5 RH70 CONTROLLER INSTALLATION PROCEDURE (RWM03)
The following paragraphs describe the mechanical and electrical installation. power checks, jumper
configurations, and visual inspection for the RH70 controller for R M03 and R M03 /R Pxx applications.
2.5.1 Mechanical
The RH70 uses one hex-height module, three quad-height modules, and three double-height modules
(Massbus connectors). There is no mechanical unit to mount. The modules are merely inserted into the
appropriate slots in the PDP-ll/70 CPU box, as shown in the module utilization chart in Figure 2-19.
The Massbus cables are plugged into the double-height slots and jumpers are configured for the proper
address and interrupt vector.
2.5.2 Electrical
The PDP-II /70 CPU mounting box contains a wired backplane that runs the full depth of the box.
The Unibus signals are prewired on the backplane. Power to the RH70 is provided by the cabinet
power supply as follows.

+ 5 V @ 18.5 A max
-15 V @ 0.5 A max
2.5.3 Module Locations
The PDP-II /70 CPU mounting box houses the flo;.l!ing-point unit, central processor, memory management, Unibus map, cache, five small peripheral controller (SPC) slots, the KWII-L clock. and up
to four RH70 controllers. The location of the respective modules is shown in Figure 2-19.
2.5.4 Massbus Cables
Massbus connections to the RH70 are made via three 40-conductor ribbon cables. These cables plug
into three M5904 transceivers in the RH70 and are designated Massbus cable A, Massbus cable B, and
Massbus cable C. The connections are made to the RH70 as shown in Figure 2-20 and Table 2-6.
2-27

SPC'S

---.
44

MASSBUS

,~(

U
B
U
S

0
U
T

MAP

CACHE

r--v

---.
29

....

5
9
0
4

8
1
5
0

5
9
0
4

8
1
5
0

.. 1

8
1
4
5

8
1
4
4

M
B
S
B

5
0

M
B
S
A

M
B
S
C

M
B
S
B

5
0

M
B
S
A

M
B
S
C

M
B
S
B

M
B
S
C

M
B
S
A

M
B
S
B

I»:.< 1
••••••••

MEM. MAN.

MASSBUS

M
B
S
C

MASSBUS

8
1
4
2

8
1
4
0

8
1

.... 3

••••

I.··· ••• :

t•. '.

••••••

:}
t---

8
1
5

8
1
5
2

8
1
5
1

M
0

8
1
5

8
1
5
2

8
1
5
1

M
0

8
1
5

8
1
5
2

M
8
1
5
1

M
0

8
1
5

8
1
5
2

8
1
5
1

0
P

M
A

C
0

0
A
.\••••••• 0
T
M 1.>/ M

1< .)

1<>

---.

'\~

.... 8

1
3
7

8
1

3
3

1
3

8
1
1
2

8
1
1
5

8
1
1
4

i<j;

3
6

i~,
L
C
C

S
S

M
8
1
3
9

S
P

T
U
B
C

T
M
C

P
0
R

A
C

R
M

X
P

:...

t-K

....

1
1

..:.:;.

I---

S
P

.. /

...

••••

I·::·.·

M
A
I
N

....

lii/

C
C
B

t-C

V:.:·;

(

FPU

I! ...•.

M
B
S
A

CPU

L
~

,B
C

A
W

S
T

B
C

.A
W

C
S
T

B
C

S
T

T
I

.A ·C
C W S

I·
.....
.

:...•.....

M
9
3
0

....

......• '.

F
\......._____- - - J I......______--..JJ

CNTLR

I..'-_ _ _ _ _--..JJ

\.______---..JJ

CNTLR

r<i

I ..•

liii

II>)

11-2942

Figure 2-19

RH70 Module Utilization Chart

2-28

PDP-11/70 REF

MASSBUS
CONTROLLER

THREE
MASSBUS FLAT
CABLES BC06R

TO PORT A OR B INPUT
ON MASS BUS ADAPTER

....,-'
FLAT TO ROUN D
TRANSITION PANEL
CONNECTOR

MASSBUS ROUND
CABLE BC06S-25

MA-0599

Figure 2-20

RH70 Massbus Cable Connections

2-29

Table 2-6

Massbus Cable A
Massbus Cable B
M assb us Cab Ie C

Massbus Cable System Configurations

Controller A

Controller B

Controller C

Controller D

AB25
AB26
AB27

AB29
AB30
AB 31

AB33
AB34
AB35

AB37
AB38
AB39

The Massbus cables are marked and should be inserted with the edge-marking facing the module
handles. A Massbus terminator pack assembly (7009938) should be plugged into the last drive attached
to the M assbus.
2.5.5 BCT and MDP Jumper Configurations
The following paragraphs describe the various jumper configurations on the BCT (M8153) module
and on the MDP (M8150) modules for both RM03 and RM03/RPxx applications.
The BCT module contains jumpers for register selection, BR level interrupt, and vector address.
2.5.5.1 Register Selection - The RH70 is capable of responding to 32 possible Unibus addresses. The
number of addresses, however, is dependent on the Massbus device. Jumpers W8-W15 select the block
of Unibus addresses that both subsystems respond to. The standard addressing block assigned is
776700-776752. For both subsystems, the jumper configuration shown in Table 2-7 should be used.

Table 2-7

RH70 Register Address Jumper
Configurations
Jumper In = Binary 0

Address
Bit

17
1

16
1

15
1

Address Bit

Jumper

Jumper In/
Jumper Out

12
II
10
9
8
7
6
5

WI4
WIO
W9
W8
WII
W13
W15
W12

Out
Out
Out
In
Out
Out
Out
In

14 13 12
111

11
I

10 9
8
101

7
1

6
5
4
lOX

3
X

2
X

0
X

'---v----' '---v----' '---v----' ""------...,---' '---v----' '---v----'
7

2-30

0 to 3

0 to 7

The jumpers in E41 (D-CS-M8153-0-1, sheet 2 of 6) are selected for the appropriate number of registers in the subsystem, minus 2. For example, there are 22 registers in the RM03 and RM03/RPxx
subsystems, so the jumpers are selected for a weighted value of 22-2 or 20, as shown in Table 2-8.

Table 2-8

RH70 Register Select Jumper
Configurations
Jumper In = Binary 0

Slot
E41

Jumper Location
Pins

Jumper In/
Jumper Out

1-16
2-15
3-14
4-13
5-12 (2)
6-11 (4)
7-10 (8)
8-9 {I 0)

Out
Out
In
In
In
Out
In
Out

2.5.5.2 BR Level Interrupt - The priority jumper plug for the RH70 is normally set for the ,BR5 level.
This plug is located in E022 (D-CS-M8153-0-1, sheet 4 of 6).
2.5.5.3 Vector Address Jumpers - The interrupt vector transferred to the processor is jumper-selectable via jumpers WI-W7, representing vector bits 2-8.
The RM03 subsystem has been assigned a vector address of 000254. The jumper configuration for this
vector address is shown in Table 2-9.
2.5.5.4 Maintenance Jumpers MDP Module (M81S0) - The MDP module contains jumpers that allow maintenance personnel to disconnect wired-OR connections from the Exclusive-OR network used
to detect write-check errors. These jumpers are designated WI-W4 and are shown on D-CS-M8150-0I, sheet 6 of 9. The jumpers provide maintenance personnel with a method of isolating a faulty output
(stuck low) of the wired-AR bus to one of four integrated circuit (IC) chips that perform the ExclusiveOR function during write-check operations. For example, if the output of the E21 and E23 opencollector line is stuck low, when scoping of the inputs indicate that it should be high, the faulty IC (E21
or E23) can be ascertained by removing jumpers W2 and WI. If, after removing the jumpers, the
outputs of the Exclusive-OR gates in E23 are still low, it indicates that the E23 chip is defective. IfE23
outputs are high, the E21 chip is defective (outputs stuck low).

2-31

Table 2-9

RH70 Vector Address Jumper
Configuration
Jumper In = Binary 1

Vector Bit

Jumper

Jumper In/
Jumper Out

V2
V3
V4
V5
V6
V7
VS

W7
W3
W6
W2
W5
WI
W4

In
In
Out
In
Out
In
Out

VS V7 V6 V5 V4 V3 V2 VI VO
010101100

'---v----' '---y---J '---y---J
2

2.5.5.5 Light-Emitting Diodes (LEOs) - The following light-emitting diodes are incorporated into the
RH70 Massbus controller logic BCT module (Figure 2-21) on the M8153.
• SSYN (Slave Sync) D-CS-MSI53-0-I, sheet 3 of 6
• TRA (Transfer) D-CS-MSI53-0-1, sheet 3 of 6
• BG IN (Bus Grant In) D-CS-MSI53-0-1, sheet 4 of 6
• SACK/(Selection Acknowledged) D-CS-MSI53-0-1, sheet 4 of 6
• BBSY (Bus Busy) D-CS-MSI53-0-1, sheet 4 of 6
These LEDs aid maintenance personnel in isolating certain system faults, as described in the following
paragraphs.
System Fault No.1 - The Unibus on the PDP-II /70 is in the "hung" condition (no operations can be
performed on Unibus).
Diagnosis - This condition may be caused by:
1.
2.
3.

Stuck SACK
Stuck BBSY
Stuck SSYN.

The LED associated with the fault condition will be illuminated continuously. (LEDs may flicker
intermittently during normal operation.)

2-32

TOP OF MODULE

TRA

cj)=

BGIN

cj)=~

SACb c:t}:

BBSY

---......,. LIGH T EMITTING
D I 0 D ES (L ED IS)

BCT MODULE( M8153)
11-2940

Figure 2-21

LED Physical Locations

2-33

System Fault No.2 - The Unibus device interrupt sequence is not functioning properly. (The processor
continuously loops in service routine and fails to execute instructions.)
Diagnosis - This condition is caused by discontinuity of the Bus Grant signal on the Unibus from the
processor to the device interrupting, and may be caused by missing grant continuity cards or defective
circuitry, which normally passes Grant signals from device to device. These will cause the BG IN LED
to become illuminated, indicating that the Unibus BG IN signal coming to the device is stuck high.
System Fault No.3 - The processor attempts to read or write a remote register in the RM03 subsystem
and receives an address error indication on the console (CPU traps to location 4).
Diagnosis - This condition may be caused by a stuck TRA signal on the Massbus that prevents the
SSYN response from the RH70. This condition can be determined if local registers in the RH70 can be
successfully accessed. If no register responds, the address jumpers may be selected improperly.
2.6

CABLING PROCEDURES

2.6.1 Ground Cabling
Two grounding studs are provided on each cabinet (Figure 2-22).
If this is a multiple-drive installation, connect a 0.9 m (3 ft) ground strap (DEC part number 7412827)
between each drive.

2.6.2 BC06S Cable Preparation
When the BC06S Massbus cable is shipped with the disk subsystem, all necessary changes to the cable
will be made at the factory. The following information is provided for those instances where a BC06S
cable is used that was not shipped with a systc::m. In such instances, some preliminary cable changes
may be needed.
The RM02/03 Massbus adapter requires that the BC06S cable exit from its connector at a 90 degree
angle. This implies that whenever this cable is used from drive to drive, both connectors need to be at
the 90 degree angle position. For the BC06S cable that goes to the RH controller, the connector at the
controller end will be at a 45 degree angle and the one at the disk drive end at a 90 degree angle.
If it becomes necessary to change the BC06S cable angle from 45 degrees to 90 degrees in the field, use
the following steps.
1.

Remove the four screws from the connector as shown in Figure 2-23a.

Examine the cable gate as shown in Figure 2-23b. Be careful not to put undue stress on the
wired connections. If the cable gate is at 0.38 inch, it should be moved forward so that only
0.25 inch of the cable sleeve remains exposed.

With the exposed cable sleeve now at the proper 0.25 inch length, adjust the cable angle to
the 90 degree position as shown in Figure 2-23c.

Replace the four screws that hold the connector together.

2-34

~/1 I

5/16_18KEPNUT~GNDSTUD~~

SEE DETAIL B

NUT5/16-18'

/
~
GND STRAP

FROMPREVIO~S ~
GROUND CABLE

DRIVE OR
CONTROLLER

GROUND CABLE
TO NEXT DRIVE

GROUND STUD

5/16 EXTERNAL TOOTH

DETAIL B

LOCK WASHER

DETAIL C
MA-0604

Figure 2-22 Grounding Studs and Cables

2-35

#6 X 1 IN. SELF TAPPING
SCREWS (SEE NOTE 2)

FIGURE (A)

CABLE GATE TO BE .25 FROM
END OF CABLE JACKET
FIGURE (B)

FIGURE (C)
MA-0916

Figure 2-23

BC06S Cable Preparation
2-36

2.6.3

Single-Port Cabling Procedure

Prior to installing the cables for single-port operation, the following steps should be taken
(Figure 2-24).

Either port A or port B may be used. The correct port transceiver modules must be in
place for each mode of operation. Two M5922 modules are needed in the position
shown in Figure 2-24 for port A operation. Port B operation requires that the two
M5923 modules be in their correct position. The status of both types of port transceiver
modules is given in Table 2-10 for each mode of operation. Each port transceiver module may be disabled independently by a switch on each board shown in Figure 2-24.

Verify that the desired jumpers are installed on the Jl connector on the MBA backplane. Table 2-11 shows how to select the correct jumper configuration.

Verify that the MBA backplane PORT SELECT switch (S 1) is in the correct position
fur the port used. Port A is CPo Port B is DO\VN. The middle position is for duai-port
programmable mode. The relationship between the PORT SELECT switch position
and the SPRT JUMPER on the MBA Jl connector is shown in Table 2-12.

The serial number of the drive is wire-wrapped into the MBA backplane on 32 wirewrap posts. There are 16 post pairs on the J4 connector shown in Figure 2-24. The last
four digits of the drive serial number are used as the RM03 serial number. A jumper
must be,installed for each logic 0 in the BCD serial number. Table 2-13 shows how to
wire a serial number of 3172.

Connect the BC06S-25 Massbus cable to the A-IN connector J3 on the MBA backplane
(Figure 2-25), and tighten the cable clamp.

CAUTION
Ensure that the Massbus cable is perpendicular to
the connector so that no stress is applied to the backplane.

If this is the last drive in the chain, install a terminator (DEC part number 7009938-00) into
the A-OUT connector J2 on the MBA backplane (Figure 2-26).

If this is not the last drive in the chain, run a Massbus cable from the A-OUT connector J2
on the MBA backplane to the A-IN connector J3 of the next drive and tighten the appropriate cable clamp.
2-37

J1 REAR VIEW
DT

-- -,
r-------------- --r--

TO
DRIVE
J2 & S3

11/0 CABLE B 26 CONDUCTOR

J1
L __
J

I I/O CABLE A 60 CONDUCTOR

DRIVE TYPE

·
I

I
I

9
60

cr-o-o

PORT 'A' OUT

Q..

1 r - J4-

I
·I
I

10 10
9

N
N

en
LO

('I')

a
0

en
~

I L ,

"'"
SN

__J

SERIAL NUMBER

0
0
0

DISABLED

PORT A LED

PROG

PORT SElCT SWITCH

PORT BLED
J6

I GRN

PORT'B' OU T

10-

"<0
"::!:

ENABLE
I

11 11

•

12 12

13 13

14 14

•I

M.R

POWER
SUPPLY
GND
STUD

J4 REAR VIEW

15 15

I
I

S
P

0-0-0-0--0

r-~

-~
J1

P51 J5

8
0

246

J 8 I 7 I 6 I 5 I 4 1 31 2 I 1

PORT 'A' IN

3
6

r--""--"

Q..

PORT 'B' IN

POWER
SEQUENCE
CABLE

J10

-------------------~-
I

-10-

I, BlK }
Ja
IN
P1
OUT

I
I

- +_J
2

FROM J9
PREVIOUS DRIVE

BlK

GRN

}

TOJa NEXT
DRIVE IN SERIES

MA-1295

Figure 2-24

Module Shall be in Slot 8
2-38

Table 2-10

Port Transceiver Module Status
Port Transceiver Module Status

Mode or Operation

MS922s

M5923s

Single port A

In place and
enabled

Removed or in place and
disabled

Single port B

Removed or in
place and disabled

In place and enabled

Dual port

In place and
enabled

In place and enabled

NOTE
Each module has its own disable switch located on its
board.

Table 2-11

Backplane Jl Connector

Jumper (Jl)

Out

1-2

3600 rev /min

Other

3-4

80MB

Other

5-6*

Single port A

Either port
or dual port

*If jumper is in place, only port A can be used.

Table 2-12

Port Select Switch
Position
PortA
PROG (A/B)
Port B

Port Select Switch Positions
MBA Backplane Jl Connection
SPRT Jumper
In

Out

Single port A
Single port A
Single port A

Single port A
Dual port
Single port B

2-39

Table 2-13

Backplane Serial Numbers

Number Bit

Serial
Jumper

1
2
4
8
10
20
40
80
100
200
400
800
1000
2000
4000
8000

In
Out
In
In
Out
Out
Out
In
Out
In
In
In
Out
Out
In
In

Resulting BCD
Serial Number

+
70

+
100

+
3000
3172

TO INPUT PORT
OF NEXT DRIVE
CABLE
BC06S-15 FT
TO
CONTROLLER

CABLE
BC06S-25 FT

MBA BACKPLANE

CABLE CLAMPS

NOTE
IF THIS IS THE LAST DRIVE IN THE CHAIN.
INSTALL A TERMINATOR ON PORT A
OUTPUT (J2).
MA-0597

Figure 2-25

BC06S Massbus Cable Connection
2-40

MBA BACKPLANE

TERMINATOR

NOTE
ALWAYS TERMINATE THE OUTPUT OF ANY
PORT THAT IS USED IF THIS IS THE LAST
DRIVE IN A CHAIN OR IF THIS IS THE ONLY
DRIVE. IN DUAL PORT DRIVES. TWO
TERMINATORS WILL BE NECESSARY.
MA-0605

Figure 2-26 Terminator Installation

2.6.4

Dual-Port Cabling Procedure
1.

Prior to installing the cables for dual-port operation, the following steps should be taken
(Figure 2-24).
a.

Verify that both port A transceivers (M5922s) and port B transceivers (M5923s) are
installed into their proper locations as shown in Figure 2-24.

Verify that jumper S-6 on the Jl connector of the backplane is left out and that the
other two jumpers are in place.

The PORT SELECT switch on the backplane should be in the programmable position.

Verify that the transceiver switches are in the enabled position.

Install the Massbus cables for dual-port operation as shown in Figure 2-27.

The Massbus terminators must be installed on the output connectors (J2 and J6), of ports A
and B whenever it is the only drive or the last drive in a string.

2-41

3 FT GROUND TO

CABLE
BC06S-2S FT
TO
CONTROLLER

MBA BACKPLANE

CABLE CLAMPS

CABLE
TO
CONTROLLER

NOTE
IF THIS IS THE LAST DRIVE IN THE CHAIN.
INSTALL TERMINATORS ON PORT B
OUTPUT (J6) AND PORT A OUTPUT (J2).

MA-0598

Figure 2-27

2.6.5

Dual Port Cabling

Power Sequence Cabling
1.

If this is the only drive or the first drive in a string, install the power sequence jumper (DEC
part number 7(09490) in J8 (power sequence IN) on the MBA backplane (Figure 2-28).

If there is more than one drive, daisy-chain the power sequence cables (DEC part number
7009491) from J9 (power sequence 0 UT) on the first drive to J8 (power sequence IN) on the
second drive, etc. (Refer to Figure 2-29.)

Verify that the ac power cord coming out of the rear panel of the disk drive is plugged into
the ac receptacle on the top surface of the Massbus adapter power supply.

2-42

J3
PORT A IN

J2
PORT A OUT

J6
PORT BOUT

NOTE
INSTALL THE JUMPER PLUG INTO J8 IF THIS
IS THE ONLY DRIVE OR THE FIRST DRIVE IN
A STRING.
MA-0664

Figure 2-28

Power Sequence Jumper

2-43

1 ST DRIVE
SUBSYSTEM

2ND DRIVE
SUBSYSTEM

LAST DRIVE
SUBSYSTEM

ADAPTER
BACKPLANE

ADAPTER
BACKPLANE
EIGHT
...--- UPTO
DRIVES TOTAL

PLUG

POWER SEQUENCE CABLE
MA-0608

Figure 2-29

Daisy-Chain Power Sequence

2.7 SUBSYSTEM CHECKOUT PROCEDURE
2.7.1

Subsystem Power Up
1.

Before plugging the main ac power cord into its power source, verify that the following steps
have been performed.
• The actuator holding pin must be inserted into its PIN STORAGE hole.
• The rear deck hold-down screw and spacer must be screwed into its KEEPER HOLE, and
the right side baseplate shipping bracket must be rotated 180 degrees.
• All four circuit breakers (two on the drive rear panel, and two on the adapter power
supply) must be in the OFF position.
• The terminals on the large capacitors should be on tightly.

Plug the disk subsystem ac power cord into its appropriate power source. Once this is done,
the ac indicator on the MBA power supply will come on.

2-44

To apply power to the subsystem, proceed as follows.
•
•
•
•
•

Switch the ac power circuit breaker on the MBA power supply to the ON position.
Switch the dc power supply breaker on the MBA power supply to its ON position.
Switch the ac circuit breaker on the drive rear panel to its ON position.
Turn ON the dc power supply circuit breaker on the drive rear panel.
Ensure that the drive's blower starts to operate and wait 2 minutes before proceeding.
CAUTION
Failure to allow the blower to operate for 2 minutes
before installing the disk pack will not allow sufficient purge time and may cause damage to the disk
pack or heads.

2.7.2

To install a disk pack and initiate a start-up sequence, follow the disk pack installation
procedures described in Paragraph 3.2.2 of the Operating Instructions.

Installation of the Field Test Unit

2.7.2.1 General Description - The TB3A2 Field Test Unit (FTU) is a portable, self-contained tester
for exercising and/or simulating on-line operations in the DEC I/O storage module drives (SMDs),
series BK5.
The FTU is housed in a suitcase-type carrying case that provides a control panel, a logic board, and an
integral power supply. The case contains space for storing the power cable, all necessary I/O cables,
and a head alignment card. The head alignment card plugs into the logic chassis of the SMD and
permits individual head alignment, using a null meter mounted in the FTU control panel.
Modes of Operation
The TB3A2 FTU provides five access (seek) modes, four read/write modes, and two modes for determining head selection.
NOTE
Performing any write operations will destroy formatting on the pack.
Access Modes
Direct Seek - The drive under test'will perform a single seek to the track number set in the CYLINDER ADDRESS switches on the FTU control panel.
Continuous Seek - The drive under test will perform repetitive seeks between any two tracks selected by
the operator. Operation will continue until the START/STOP switch on the FTU control panel is
moved to STOP (STOP switch actuated).

2-45

Sequential Forward Seek - The drive under test will perform single-track incremental seeks until the
last track is reached, then seek to track 00, and continue incremental seeks in the same manner until
the STOP switch is actuated.
Sequential Reverse Seek - The drive under test will perform single-track decremental seeks, starting
with the track nominated by the CYLINDER ADDRESS switches, until track 00 is reached. The drive
will then return to the nominated track and repeat the operation until the STOP witch is actuated.
Random Seek - The drive under test will perform seeks to random tracks as selected by a free-running
counter within the FTU. Operation will continue until the STOP switch is actuated.
Read/Write Modes
The TB3A2 FTB generates serial NRZ write data at a rate determined by the servo clock signals
transmitted from the unit under test. When a repeatable access mode is selected (that is, any mode
except direct mode), a read/write operation will be completed at the selected cylinder, after which a
seek will be initiated to the next cylinder address (as determined by the access mode) and the
read/write operation repeated. This seek-read/write sequencing will continue until the STOP switch is
actuated or an error occurs. For direct seeks, the read/write R/W operation will continue at the
selected track or cylinder (depending upon the head select mode) until the STOP switch is actuated.
The number of tracks read or written during each read/write operation is controlled by the mode of
head selection chosen. For manual head selection, only the track under the head selected by the HEAD
ADDRESS switches will be read or written. For sequential head selection, the heads will be sequenced
so as to read or write each track in the cylinder. When the highest-numbered head (or cylinder track)
has been exercised, the drive will seek to another cylinder (except in direct seek) and the read/write
operation will be repeated at that new cylinder, starting with head 00.
Write Format - When the FTU WRT-RD SELECT switch is set to WRT FORMAT, the FTU will
write each selected track with the appropriate track address and a repetitive 8-bit data pattern that has
been set in the DATA PATTERN switches on the FTU control panel. The FTU also provides a means
for indicating a defective track when using the write format mode.
Write - When the FTU WR T -RD SELECT switch is set to WR T, the FTU will write the repetitive 8bit data pattern on the selected track, after having first read and verified the track address.
Read - When the FTU WRT-RD SELECT switch is set to RD, the FTU will read the data from the
selected track, after having first read and verified the track address.
Write Then Read - When the FTU WRT-RD SELECT switch is set to WRT.RD, the FTU will verify
the track address and write the 8-bit data pattern on the selected track during one revolution of the
drive, then verify the track address, and read back the data during the second revolution.
A fifth position (OFF) of the WRT -RD SELECT switch is available for access only operations. This
position is also used during the head alignment procedure.
2.7.2.2

Tester Installation

Operating VoJtage
The FTU is connected at the factory for use with a 120 Vac 50/60 Hz power source. To reconnect for
240 Vac operation, proceed as follows.
1.

Open the FTU cover. Unhinge the cover and set it aside if necessary.

2-46

Raise the control panel.

Remove head alignment card from its compartment on top of the power supply box.

Remove four screws securing the cover plate of the power supply; remove the cover plate.

Remove the jumper straps connecting terminals 1 and 2, and terminals 3 and 4 of A ITBI
(Figures 2-30 and 2-31).

Instali both jumpers so as to connect terminals 2 and 3.

Replace and secure the power supply cover plate.

Replace the head alignment card in its compartment.

Procure a 120 to 240 Vac conversion plug from a local supply house and attach it to the
FTU power cord plug. Alternatively, remove the molded 3-prong plug attached to the FTU
line cord and install one suitable for 240 Vac receptacles.

The FTU is now ready for 240 Vac operation.

NOTES:

&
&

VOLTAGE POT (SCREWDRIVER ADJ)
OVERVOLTAGE POT (SCREWDRIVER ADJ)
MA-1423

Figure 2-30

FTU Power Supply Layout

2-47

-5 V DC SUPPL Y

OUTPUT

SENSE

OUTPUT

SENSE

+5 V DC SUPPLY

-VCC

OUTPUT

SENSE

OUTPUT

SENSE

FAN
MI

+VCC

+5V

1:\.3

~-5V
NOTES:
6.WIRING SHOWN FOR 110V OPERATION

CASE

&GND

LOGIC BOARD +5 V BUS
CONTROL PANEL BOARD
+5 V BUS
CONTROL PANEL BOARD
-5VBUS

' - - - - - - - r - LOGIC BOARD GND BUS

FOR 220V OPERATION, JUMPER 1-2 AND 3-4 ARE
REMOVED AND JUMPER 2-3 IS ADDED. THE
RESULTANT IS SHOWN BELOW

CONTROL PANEL BOARD
GND BUS

A'~LJ tj3 ~4
1\ THESE ARE REPLACED AS A UNIT AND THEREFORE

~INDIVIDUAL COMPONENTS (OTHER THAN TRANSFORMERS) ARE NOT SHOWN
6.REFER TO KEY TO LOGIC FOR +5 V, -5 V AND GND BUS CONNECTIONS

Figure 2-31

FTU Power Supply Wiring Diagram

2-48

MA-1422

I/O Cables
Two I/O cables are provided. The A-cable has a 75-pin block-type connector on one end and a 6O-pin
flat-cable connector on the other end for connection to the drive. The B-cable is equipped with a 34-pin
block-type connector on the tester end and a 26-pin flat-cable connector on the drive end (Figure 2-32).
Head Alignment Cable
SMD head alignment using the TB3A2 FTU requires installing the special head alignment card in the
proper position of the drive logic chassis, and connecting the 4-wire head alignment cable between the
logic chassis and the appropriate jack in the drive's read/write assembly. Figure 2-33 gives the connecting information. A pair of test leads (provided) is then installed between the banana jacks on the
head alignment card and the null meter on the FTU control panel.
2.7.2.3 Controls and Indicators - Except for the power switch and circuit breaker mounted on the
power supply box, all controls and indicators for operation of the TB3A2 FTU are located on the
control panel (Figure 2-34). The controls and indicators are described below, moving from top left to
bottom right across the panel.
+5V,-5V
indicators

Indicate that the respective power supply voltages are present.

SERVO OFFSET
switch

A 3-position switch with center "off."

Commands the drive to offset the carriage in
the positive direction (toward the spindle).

Center

Nominal positioning (no offset).
Commands the drive to offset the carriage in
the negative direction (away from the
spindle).
NOTE
The START/STOP switch must be actuated to effect any change in offset by the
drive when in direct mode.

DATA STROBE
switch

A 3-position switch with center "off."
EARLY

Moves the drive's read strobes from nominal
to an earlier time with respect to data.

Center

Drive strobes at nominal timing.

DATA STROBE
switch (cont)

LATE

Moves the drive's read strobes from nominal
to a later time with respect to data.

WRT FLAG
switch

When moved up, this switch causes a Defective Track flag bit to be
inserted in Bit 6 of Address Word 1, provided that:
• WRT-RD SELECT switch is set to WRT FORMAT.
• ACCESS MODE switch is set to DIRECT.
• Head-select switch (SEQ-MAN) is set to MAN.

2-49

P3B
60-PIN FLAT
CONNECTOR

P2B
26-PIN FLAT
CONNECTOR

MA-0610

Figure 2-32

Tester I/O Cables

2-50

Pl04
PLUGS INTO JACK ON CARD IN
RIW CHASSIS OF DRIVE
P8
FITS OVER WIW PINS FOR
HEAD ALIGNMENT CARD SLOT
IN DRIVE LOGIC CHASSIS
MA-0662

Figure 2-33

Head Alignment Connections

2-51

DATA
STROBE
SERVO
OFFSET
WRT
+5V -5V + EARLY FLAG

0 0 @@ @
-

LATE
SE~

WRT
PWR INHIBIT

XTAL MAINT

SERVO NRM

OFF

NRM

INITIALIZE

TPI
LO

DISPLAY SELECT

~CYLINDER
.... --HD+ERR CNT

HEADS
5 (LO)

SMD

19 (H Ii

PLUG
VALID

,UNIT

UNIT CLK
SEL ERR

0 0

ERR BYPASS
ADDR DATA

S-C S-M WRT
ERR ERR PROT

0 0 0

0 0

0 00

ON I
I CYL

000

0 0 0
8

o 00
5

000
2

DATA PATTERN

'@ @

DIRECT
CONT
RAND

WRT
RD
WRT'READ
OFF

SEC
SEEK
30 32 ERR

DISPLAY

~SEQREV
r--SEO FWD

~WRTFORMAT

ADDR DATA
ERR
ERR

WRT-RD SELECT

@ @ @ @ ~ SEC
4

CHARCNT
READ DATA
UNIT NO.

ACCESS MODE

HI
MMD

UNIT
READY

FAULT

RUN

@@@I
2

@DATA
ERR

@SECTOR
MARK

@INDEX
MARK

@~~L

@READ
DATA

@WRITE
DATA

t @BITS---.

o 5

@
@4

WRT READ

@@@

@ADDR
ERR

CYLINDER ADDRESS

@ @

@ ~@

1024 512

256

128

@ @<~
32

@®(~
4

@9
@3
@8

1
@2

RTZ

START

RESET STOP

FIXED
BOTH@
MOVABLE

SEa

~ HEAD ADDRESS

®@@

MAN

-:l

<~@@
4

@7
@1
@6
@o
@

@WRITE
CLK
@READ
ClK
@WRITE
GATE
@READ
GATE
@CYL
SELECT

@HEAD
0 SELECT

o GND @CONTROl
SELECT
MA-0638

Figure 2-34 TB3A2 Control Panel
2-52

XTALjSERVO
switch

MAINTjNRM
switch

SEQ PWRjOFF
switch

XTAL

A crystal oscillator within the FTU provides a
nominal 9.667 MHz clock signal. Used for
tester maintenance.

SERVO

Servo Clock signals from the drive provide
the basic timing for the FTU.

MAINT

U sed to perform maintenance on the FTU
without a drive connected. Provides pseudo
Ready and On Cylinder signals to simulate a
drive response. It is also used during head
alignments.

NRM

Normal testing of a drive is done in this position.

SEQ PWR

In this position, the FTU commands the drive
to power-up, provided that:
• The drive is in the remote mode.
• Primary power is available at the drive.
• The drive's START switch is ON (indicator lighted).

WRT INHIBIT /NRM
switch

OFF

In this position, the FTU cannot power-up
the drive.

WRT

Prevents writing by the drive.

INHIBIT

Writing is inhibited even though all other
FTU switches are set to perform a write operation.

NRM

Allows a normal write operation in the drive,
provided that other FTU switches are set to
perform a write operation.

INITIALIZE

When moved to the "up" position, this momentary-contact switch
provides an Initialized signal to the drive under test.

TPI switch

Not used; position irrelevant.

MMDjSMD switch

Not used; position irrelevant.

HEADS switch

Not used; position irrelevant.

PLUG VALID
switch

With FTU's DISPLA Y SELECT switch set to UNIT NO. so as to
display the PLUG VALID indication, proceed as in Tahle 2-14,

2-53

Table 2-14 Plug Valid Indication

''0'' Display Light
(Plug Valid
Indicator)
ON

Meaning

To Select Drive

Logical address plug is installed in
drive.

1. Set PLUG VALID switch "up."

2. Set the three UNIT switches to desired drive number (0-7).
OFF

Logical address plug is not installed in drive.

1. Set PLUG
"down."

VALID switch

2. Set all three UNIT switches
"down" to pseudo-select unit O.

UNIT
switches

421

SEC 30/32 switch

Selects the drive under test for either 30- or 32-sector operation.

ACCESS MODE
switch

A 5-position rotary switch that controls the seek (access) mode of
the drive under test.

U sed to indicate the binary value of the three
Select Address lines to the drive. This code
must match that of the logical address plug in
the drive under test.

SEQ REV

Sequential Reverse - The drive seeks to the address in the FTU CYLINDER ADDRESS
switches, sequences down to 0, and then repeats.

SEQ FWD

Sequential Forward - The drive performs a
series of incremental seeks, starting with the
address that is in the cylinder address register
(CAR) at the start of the operation. When
maximum cylinder address is reached, the
cycle begins again at address O.

DIRECT

The drive seeks to the address in the CYLINDER ADDRESS switches. Seeking to another address requires changing the address in
the switches and manually initiating another
seek operation by actuating the START
switch.

2-54

ACCESS MODE
switch (cont)

DISPLAY SELECT
switch

DISPLAY SELECT SWITCH
POSITION
CYLINDER

HD + ERR CNT

CONT

Continuous - The drive seeks alternately between the address in the CYLINDER ADDRESS switches and that in the cylinder
address register. The contents of CAR does
not change during this operation.

RAND

Random - The drive seeks to random addresses generated by increasing the count in
the CAR during the time that the drive is not
"on cylinder."

A 5-position rotary switch that controls the eleven DISPLAY
lamps on the FTU control panel. The interpretation of the display
is shown in Figure 2-35. When the switch is set on READ DATA,
the cylinder address will be displayed as long as the FTU is running. The data pattern read will be displayed if the FTU has
stopped because of a data error; otherwise the display will be Os.
tr--------DISPLAY-BIT LED's---------..

000

512

256 128 64

000

1
2
LERROR COUNT-.J

CHAR CNT

READ DATA

000
2

2
8
4
1
L-HEAD REGISTER--.J

000

- 8192

4096 2048 1024

512 256 128

000

00
UNIT NO.

7
7
I

6
6

4
4

3
3

2
2

000
5

4
4

0
0

READ BITS

000
7

5
5

000
2

1 PLUG
VALID
MA-0639

Figure 2-35

Display Select Switch
2-55

WRT-RD SELECT
switch

A 5-position rotary switch that determines the manner in which
data will be exchanged between the FTU and the drive under test.
WRT
FORMAT

Write Format - Writes the correct track address (HA and CA) and a preselected 8-bit
data pattern field on each selected track. The
format is as shown in Figure 2-36.

NOTE
This format is not the same as the standard DIGITAL format.
WRT

Write - Writes a preselected pattern in the
data field of each selected track, after first verifying the track address.

Read - Verifies the track address, then reads
the selected track.

WRT.READ

Write Then Read - Verifies the track address,
writes the data field on the selected track, then
reads the track. (Operation requires two revolutions.)

ADDRESS
FIELD

!
r

ZEROS

HOME ADDRESS
PROTECT GAP

ADDRESS WORD 1 \ ADDRESS WORD 2\ ADDRESS WORD 3\

'----v-----'
HEAD
ADDRESS

WRITE FLAG BIT

I- I

DATA{I}LD

ZEROS

CYLINDER
ADDRESS

INDEX
GAP

(

I DATA WORD 1 I DATA WORD 2 I

"O"INDICATES
UNUSED BIT
DATA SYNC BIT

ADDRESS SYNC BIT

a-BIT DATA PATIERN
IS REPEATED FOR THE
ENTIRE DATA FIELD,
EXCEPT THAT BIT 7 OF
WORD 1 IS A SYNC BIT

MA-0641

Figure 2-36 Track Format

2-56

WRT-RD SELECT
switch (cont)

OFF

ADDR ERROR
indicator

Indicates that the address information received from the drive
differs from the address requested, or that the address sync bit was
not received from the drive.

DATA ERROR
indicator

Indicated that the 8-bit data pattern received from the drive differs
from the pattern set in the DATA PATTERN switches.

ERROR BYPASS
switches

ADDR

Address - If this switch is in the "up" position, it allows the FTU to continue operating
when an address, S-C, or S- M error occurs. In
the "down" position, an address error will
stop the FTU.

DATA

If this switch is in the "up" position, it allows
the FTU to continue operating when a data
error occurs. In the "down" position, a data
error will stop the FTU.

RUN indicator

Disables all read/write functions; restricts the
drive under test to seek operations only.

Indicates that the FTU is running or that the RTZ switch (Returnto-Zero) is being actuated. Five conditions will turn off the indicator.
• Returning the RTZ switch to neutral (but provided that
RUN was not lit before the RTZ operation)
• A valid (unbypassed) error
• Actuating the STOP switch
• Actuating the RESET switch
• If the Ready signal from the drive goes low

WRT indicator

Indicates that the FTU is writing.

RD indicator

Indicates that the FTU is reading.

RTZ/RESET
switch

A 3-position momentary switch with center "off."
RTZ

Clears HAR and CAR; clears the drive's fault
register and causes the drive to perform a return-to-zero seek. The RUN light on the FTU
control panel will be lit as long as this switch
is actuated to the RTZ position.

Center

Neutral position.

RESET

Clears the error flip-flops in the FTU and the
drive. This switch must be actuated after a
valid error has occurred in order to be able to
restart the FTU.

2-57

START/STOP
switch

A 3-position momentary switch with center "off."
START

Generates a pulse that starts the FTU; turns
on the RUN indicator. An existing error condition must be cleared by actuating the RESET switch before START will have any
effect.

Center

Neutral position.

STOP

Stops the FTU; extinguishes the RUN indicator.

UNIT SEL
indicator

Indicates that the unit number of the drive under test agrees with
that set in the UNIT NO. switches on the FTU, and that the tester
is receiving a Plug Valid signal from the drive.

CLK ERROR
indicator

Indicates that a period of 200 ns has expired without a servo clock
pulse from the drive under test.

S-C ERROR
indicator

Indicates that the sector counter in the drive under test does not
agree with the sector counter in the FTU.

S-M ERROR

Indicates that an incorrect number of sector marks was received
from the drive under test between successive index marks.

WRT PROTECT
indicator

Indicates the presence of a Write Protect signal from Jthe drive
under test.

SEC 30/32
indicator

Indicates whether the drive is in 30 or 32 sector mode.

SEEK ERROR
indicator

Indicates the presence of a Seek Error signal from the drive under
test.

FAULT
indicator

Indicates the presence of a Fault signal from the drive under test.

ONCL
indicator

Indicates the presence of an On Cylinder signal from the drive
under test, or a pseudo On Cylinder signal generated by the FTU if
in maintenance mode.

UNIT READY
indicator

Indicates the presence of a Ready signal. This signal comes from
the drive if the A and B I/O cables are connected between the drive
and the FTU.

DISPLAY
indicators

Refer to diagram shown for the DISPLAY SELECT switch (Figure 2-35).

DATA PATTERNS
switches

These switches permit setting the repetitive 8-bit data pattern that
is written in the data field of the selected track during a write operation. For read operations, the data read from the track is compared with these switches to check for the presence of a read error.
A 1 is indicated when a switch is in the "up" position, a 0 when the
switch is "down."
2-58

CYLINDER ADDRESS
switches

These switches enter the binary value of the cylinder address to
which a seek is desired. Used in conjunction with the ACCESS
MODE switch. A 1 is indicated when a switch is in the "up" position, a 0 when the switch is "down."

FIXED/BOTH
MOVABLE switch

Not used. Reserved for future use with MMDs.

SEQ/MAN

This switch determines the manner in which the head address is
selected.
SEQ

Sequential - After performing a write or read
operation, the FTU increases the count in the
head address register by 1 for each index mark
or, when in random, for each access. When
the count is maximum (5 or 19), head zero is
the next head selected, and the incrementing
continues.

MAN

Manual - The FTU will select the head address set in the HEAD ADDRESS switches.

ADDR ERROR
test point

This test point goes to a logical 0 when an address error occurs.

DATA ERROR
test point

This test point goes to a logical 0 when a data error occurs.

SECTOR MARK
test point

This test point goes to a logical 1 when the FTU receives a Sector
Mark signal from the drive under test.

INDEX MARK
test point

This test point goes to a logical 1 when the FTU receives an Index
Mark signal from the drive under test.

ONCYL
test point

This test point will be a logical 0 when the drive under test is On
Cylinder.

READ DATA
test point

This test point reflects the binary value of the serial data bits being
received from the drive under test during a read operation. The
test point is inoperative during maintenance mode.

WRITE DATA
test point

This test point reflects the binary value of the serial data bits being
processed by the FTU during a write operation ("0" = 0, "1" =
I). The indication is valid for any write operation, even though the
FTU is in the maintenance mode. The test point remains a logical
o during read operations.

BITS 0-9
test points

These ten test points reflect the logical value of the bus-out bits
(BOB) delivered to the drive under test via the A-cable. Logically,
these bits are present in the FTU's bus-out multiplexer, and are
available at the test point panel regardless of the operating mode
(including maintenance mode) of the TB3A2. For an interpretation of the specific bus-out bits, see Table 2-15.
2-59

Table 2-15

FfU Test Points

Signal Name

Function - A-Cable (To Drive)

Tag Bus Lines

Three lines that define the operation to be performed by the drive. Tag 1 gates the
cylinder address and initiates the seek. Tag 2 gates the head address. Tag 3 is the
control select that gates the function to be performed.

Bus-Out Lines

Tag 1

Tag 2

Tag 3

Bit 0

Write Gate - Enables write circuits in drive unless drive is write
protected.

Bit 1

Read Gate - Enables read circuits in drive.

Bit 2

Servo Offset Plus - Offsets the actuator from the nominal On
Cylinder position toward the spindle.

Bit 3

Servo Offset Minus - Offsets the actuator from the nominal On
Cylinder position away from the spindle.

Bit 4

Fault Clear - Pulse to clear the fault summary flip-flop in the
drive.

Bit 6

RTZ - Pulse that causes the drive actuator to seek to track O.

Bit 7

128

Data Strobe Early - Enables the drive's PLO data separator to
strobe the data at a time earlier than optimum.

Bit 8

256

Data Strobe Late - Enables the drive's PLO data separator to
strobe the data at a time later than optimum.

Bit 9

GND
test point

This test point is a common ground point between the FTU logic
board and the control panel.

WRITE CLK
test point

This test point reflects the logic level of the 9.667 MHz Write
Clock signal that the FTU sends to the drive under test during any
write operation.

READ CLK
test point

This test point reflects the logic level of the 9.667 MHz Read Clock
signal received from the drive under test during any read operation. A read error forces the test point to logical O.

WRITE GATE
test point

A logical 1 at this point indicates the presence of a Write Gate
signal generated by the FTU during any write operation.

READ GATE
test point

A logical 1 at this test point indicates the presence of a Read Gate
signal generated by the FTU during any read operation.
2-60

CYL SELECT
test point

This test point goes to a logical 1 when the FTU sends a Cylinder
Select signal (Tag 1) to the drive.

HEAD SELECT
test point

This test point goes to a logical 1 when the FTU sends a Head
Select signal (Tag 2) to the drive.

CONTROL SELECT
test point

This test point goes to a logical 1 when the FTU sends a Control
Select signal (Tag 3) to the drive.

2.7.3

Operation of the Field Test Unit (FTU)

2.7.3.1 General Description - The TB3A2 FTU is used to pin-point a problem in the drive, once the
nature of that problem has been defined. Suppose, for example, that a drive is suspected of intermittent
read errors. The TB3A2 can be set up to repeatedly write and read back any chosen data pattern on a
given track, on the entire pack, on any portion of the pack between two selected cylinders, stopping
when an error occurs.
By making several such error-stop passes, and by using the DISPLAY SELECT switch to identify the
cylinder, head, character count, and the data pattern read for each error stop, the FE can create a
record of error parameters that will provide a failure pattern for pin-pointing the problem.
The character-count display provides an indication of how far from index the error occurred. If you
suspect a bad spot on the disk because errors consistently occur for the same head (track) and cylinder,
the character count can confirm it. If the character count is random for that situation, suspect intermittent data failures on the selected head rather than a bad spot on the disk.
That is to say, the degree of flexing to which the head lead is subject at a particular head/arm location,
plus machine vibration, might cause read/write errors; but they would most logically be random
errors, not occurring at the same spot for every revolution of the disk. Discriminations between random errors and bad spots are important when writing the track format on a new scratch pack, as
described in the operating procedures (Paragraph 2.7.3.3).
Data and address errors are the most prevalent causes for failure. The TB3A2 FTU provides bypass
switches for each of these errors. This allows the FTU to alternately write and read a suspected track
(or cylinder or pack area) for an extended period without stopping when an error of this type appears.
After the test, the error count display will show the number of errors that occurred during the test
period, up to a maximum of 15.

2.7.3.2

Preliminary Setup
1. At the drive, disconnect the A and B I/O cables running to the drive controller; connect the
A and B adapter cables, provided with the FTU, between the drive and the tester.

2. Take steps to ensure that the system will not attempt to select the drive while that drive is
being exercised by the FTU.
3.

Remove ac power from the drive and make the I/O cable connections as determined in step
1. Do not reapply ac power to the drive.

4. Set the SEC (sector) switch on the FTU panel to 30 or 32, as desired for the drive under test.
2-61

5. Set the following switches as shown for normal testing.
Switch

Position

SEQPWR
SERVO OFFSET

Up
Center (off)

DATA STROBE

Center (normal)

WRTFLAG

Down (off)

XTAL/SERVO

SERVO

MAINT/NRM

NRM

WR T INHIBIT /NRM

NRM

PLUG VALID

UNIT (3 switches)

To logical address of the drive

ADDR ERROR/BYPASS
DATA ERROR/BYPASS
(2 switches)

Both down (off)

6. Turn on the FTU.
7. Apply ac power to the drive. The UNIT SEL indicator should light up, as will the WRT
PROT indicator if the drive under test is in the write protect mode.
8. Install a scratch pack on the drive to be tested.
9.

Power up the drive. The WRT PROT lamp, if on, will go out when the drive is up to speed.
The UNIT READY lamp will light up when the heads are loaded.

10. Actuate the INITIALIZE switch.
11. Actuate the RTZ switch, then the RESET switch on the FTU panel.
The drive is now ready for exercising. It has performed a seek to cylinder 0 and has selected head O.
The remaining switches on the FrU panel may now be set for the desired function and operating
modes, as illustrated in the operating procedures (Paragraph 2.7.3.3).

2.7.3.3 Operating Procedures - The first five of the procedures described below embody every access,
read/write, and head-select mode provided by the TB3A2. Paragraph 2.7.3.3.6 checks the data error
logic and Paragraph 2.7.4.1 describes the use of the head alignment card.
Continuous Seek, No Read/Write - This procedure performs alternate seeks between the cylinder
address in the CAR and the address set in the CYLINDER ADDRESS switches.
1. Ensure that the FTU switches are positioned as described in the preliminary setup procedure
(Paragraph 2.7.3.2). In addition, position the following switches as shown.
Switch

Position

DISPLAY SELECT
WRT-RD SELECT

CYLINDER
OFF
2-62

Set the CYLINDER ADDRESS switches to the value of one of the cylinder address to
which the drive will seek. (For illustration, choose CAS.)

Set the ACCESS MODE switch to DIRECT.

Momentarily actuate the START switch. When the ON CYL indicator is lit, move the
switch momentarily to STOP. Address S is now in the CAR, and will be displayed on the
panel.

Set the CYLINDER ADDRESS switches to the value of the second cylinder address. (For
illustration, choose CAI6.)

Set the ACCESS MODE switch to CONT.

Actuate START. The drive will perform alternate seeks between addresses Sand 16. The
ON CYL indicator will blink rapidly as the heads move on and off cylinder. The cylinder
address display lights will alternate between Sand 16.

Stop the FTU.

9. Actuate RTZ.
10.

Start the FTU. The tone of the drive will change as it now seeks between cylinders 0 and 16.
Observe the display.

II. To stop the operation, actuate either STOP or RESET.

Random Seek, No Read/Write
l.

Maintain the preliminary setup switch positions (Paragraph 2.7.3.2, step 5). In addition, set
the following switches as shown.
Switch

Position

DISPLA Y SELECT
WRT-RD SELECT
ACCESS MODE

CYLINDER
OFF
RAND

Actuate START.

Ensure that cylinders are being selected randomly by observing the changing pattern on the
display lamps.

Stop the FTU by actuating STOP or RESET.

Write Format - This procedure is used to write a prescribed format on every track of the disk pack.
The next procedure, read, determines whether any of the tracks so written contain errors. The final
procedure, write flag, shows how to select a single track, write a "defective track" flag bit on that
track, and check to ensure that the flag bit was indeed written. The track format is shown in Figure 236.
2-63

Maintain the switch positions as given in the preliminary setup procedure (Paragraph
2.7.3.2, step 5). In addition, set the following switches as shown.
Switch

Position

DISPLAY SELECT
ACCESS MODE
WRT-RD SELECT
CYLINDER ADDRESS
SEQ/MAN
HEAD ADDRESS
DATA PATTERN

READ DATA
SEQ FWD
WRTFORMAT
All down (off)
SEQ
All down (off)
70 octal

Move RTZ/RESET switch to RESET, then to RTZ.

Actuate START. Observe the progression of the display lights as the drive moves away from
cylinder o. (With the DISPLAY SELECT switch set to READ DATA, the cylinder address
is displayed while the FTU is running.)

If an error stop occurs, remove the cause of the error by proceeding as indicated in the
trouble analysis chart in Table 2-16. (Data errors will not occur during WRT FORMAT.)
Then proceed as follows.

Actuate RESET to clear the error indication in the FTU.

Actuate START. This rewrites the track that was selected when the error occurred,
then continues the write format operation.

Do not actuate RTZ. To do so would cause the operation to begin anew at cylinder 0,
head o.

After all tracks have been written, stop the FTU. (Writing will begin again at cylinder 0, so
the actual stopping point is immaterial.)

Read - This operation tests the entire data pack for errors, using the sequential reverse access mode.

Set the following switches as shown. All others should remain as given for the write format
procedure.
Switch

Position

DISPLAY SELECT
ACCESS MODE
WRT-RD SELECT

CYLINDER
SEQ REV
RD

Set the CYLINDER ADDRESS switches to the maximum cylinder address (822 decimal)
The switch settings are as follows.

OFF

512
256
32
16
4
2

1024
128
64
8
I
2-64

Table 2-16

Trouble Analysis (Sheet 1 of 3)

Assume:
1.
2.
3.
4.
5.
6.

A & B I/O cables connected between drive and FTU.
Power applied to FTU and drive.
+ 5 V indicators on FTU panel are lit.
DATA/ADDRESS BYPASS switches OFF.
FTU set to READ track format.
READ indicator comes on when START switch (on FTU panel) is actuated.

Conditions

Seek error

Clock error in SERVO position

Clock error in XT AL position

Sector M ark Error

Sector Count Error

Drive Fault

Go to sheet 2, "Conditions."

Actuate RESET, RTZ, START.

Refer to drive service manual.

Check TP5 (W RITE CLK) on FTU panel.

Refer to FTU diagrams.

Actions

Set XTAL-SERVO switch to XTAL;
Actuate RESET, START.

Check B-cable for SERVO CLK signal. Troubleshoot
discontinuity in drive, cable, FTU.
Check that sector switch (SEC) in FTU is set correctly.

Check TPI (SECTOR MK) on FTU panel.

Check TPO (INDEX MK) on FTU panel.

Upper-Left Quadrant:

Assumptions needed for tests, as well as the test conditions.

U pper- Right Quadrant:

Results of the test: N = No; Y = Yes; - = Don't care.

Lower- Left Quadrant:

Actions to be taken for each test result.

Lower-Right Quadrant:

Numbers show sequence of actions for the test results in a given column.
After each action, the test is repeated and, if X = a "no error" or "problem solved" situation.

2-65

Table 2-16 Trouble Analysis (Sheet 2 of 3)
Conditions

A ddress error

Data error, OFFSET and DATA STROBE switches in center (off) position

Track was read without error.

Perform WRT FORMAT for track in error; READ rewritten track.

Perform WRT.RD retry as follows.

Actions

Set FTU switches as indicated below.
Switch

Position

WRT-RD SELECT
ACCESS MODE
SEQ/MAN
HDADRS
CYLADRS

WRT.RD
DIRECT
MAN
Select
Failing track

Actuate START; check for conditions 11 or 12 on following page of table.
Unrecoverable error. Perform WRT FLAG procedure for track in error.

2-66

Table 2-16

Trouble Analysis (Sheet 3 of 3)

Conditions

Data error on WRT.RD retry

Data error, OFFSET switch in + (FWD) position

Data error, OFFSET switch in - (REV) position

Data error, DATA STROBE switch set
EARLY

Data error, DATA STROBE switch set
LATE

Actions
Set OFFSET switch to + (FWD) position;
READ track in error.

Check Bit 2 TP on FTU panel; if missing, refer to FTU diagrams.·

Check BOB2 in drive; if missing, check I/O
cable and FWD offset logic in drive.·

Set OFFSET switch to - (REV) position;
READ track in error.

Check Bit 3 TP on FTU panel; if missing, refer to FTU diagrams.·

Check BOB3 in drive; if missing, check I/O
cable and REV offset logic in drive.·

Return OFFSET switch to center (off); set
DATA STROBE switch to EARLY. Read
track in error.

Check Bit 7 TP on FTU panel; if missing, refer to FTU diagrams.·

Check BOB7 in drive; if missing, check I/O
cable and Early Strobe logic in drive.·

Set DATA STROBE switch to LATE; Read
track in error.

Check Bit 8 TP on FTU panel; if missing, refer to FTU diagrams.·

Check BOB8 in drive; if missing, check I/O
cable and Late Strobe logic in drive.·

Drive has demonstrated its ability to recover
data.

Unrecoverable error. Perform WRT FLAG
procedure for track in error.

·When checking for the presence of these bits, the DATA ERROR BYPASS switch must be on ("up" position). This allows
reading to continue in the event of an error. The switch should be off ("down" position) when checking for the conditions.

2-67

Actuate START. Reading will begin at maximum cylinder, head o. Should an error occur,
the RUN light will go out and the panel lamps will display the type of error, as well as the
cylinder that was being read when the error occurred. Follow steps 4 and 5 for each separate
error stop. If no errors, skip to step 6.

Record the error parameters, moving the DISPLAY SELECT switch as needed.
NOTE
It is not necessary to record the ERROR COUNT.
This will remain at count 1 for any stop-on-error operation.

After the error parameters have been recorded, actuate RESET to clear the error indication
in the FTU, then actuate START to continue reading.

When the FTU begins reading again at the maximum cylinder address, actuate STOP to halt
the FTU.

Write Flag - A single read may produce random errors that in an on-line environment would be
eliminated by the system's error-recovery program.
Before flagging a track as bad - that is, as one that continually produces errors that are not recoverable
- it is best to WRT.RD the track several times. If the error persists, the trouble analysis procedure
(below) should be executed in an effort to recover the error. Only after both of these attempts have
failed, should the track be flagged.
This procedure writes a "defective track" flag bit in Bit 6 of Address Word 1 (Figure 2-36).

Set the following FTU switches as indicated. Other switches should remain as shown for the
preliminary setup procedure (Paragraph 2.7.3.2, step 5).
Switch

Position

WRTFLAG
DISPLAY SELECT
ACCESS MODE
WRT-RD SELECT
DATA PATTERN (8)
CYLINDER ADDRESS (11)
HEAD ADDRESS (6)
SEQ-MAN

Up (on)
READ DATA
DIRECT
WRTFORMAT
As set when the track was most recently written
To select the track
To be flagged
MAN

Actuate RESET, then START. Drive will seek to the selected track.

When ON CYL light comes on, wait about 1/2 second and then actuate STOP.

Set WRT -RD SELECT switch to RD.

Actuate START. The "defective track" flag bit will prohibit reading the track. The ADDRESS ERROR and DATA ERROR lights should not light up.

Actuate STOP.
2-68

Repeat steps 1 through 6 for each track to be flagged as defective.
NOTE
The WRT FLAG switch must be turned off before
reading a track that has not been written as defective; otherwise an address error will occur.

Check Data-Error Logic - This procedure assures the operator that data errors will be recognized by
the FTU. It is used when the FTU is exercising a drive in any situation where data errors are expected
but none occur - an intermittent read failure, for example. It assumes that the procedure in question is
still running and that the scratch pack therefore has a data field written on the tracks being tested.
J.

Stop the FTU.

Set the following FTU switches as indicated.
Switch

Position

WRT-RD SELECT
UA IA ERRuR Ii ~i PAS~
DATA PATTERN

RD
Down {ott)
Choose anyone switch and move it to the
opposition position. (Move just one!)

All other switches must remain as they were at the start of the procedure being questioned.
3.

Start the FTU. The FTU should stop with the DATA ERROR indicator lit.

Actuate RESET to clear the error indication.

Set the DATA ERROR BYPASS switch up (on).

Actuate START. The FTU should run without stopping on an error, but the RD/WRT
ERROR counter will count the errors (up to 15).

Stop the FTU. Return all switches used during this procedure to the state they were in at the
start of the procedure being questioned.

Trouble Analysis - Table 2-16 is a decision logic table (DL T). It shows the procedures the operator
should take to eliminate any error that might occur when using the FTU to exercise a drive. Address
and data errors will, of course, occur only during one of the read or write modes. Other errors may
occur for either read/write or access only (no read/write) modes. It should be noted that sector mark
and sector count errors are not indicated if the ADDRESS ERROR BYPASS switch is active.
Basically. the DL T deals with attempts to either eliminate or recover data and address errors before
writing a "defective track" flag on the track in error. This involves trying various OFFSET and OAT A
STROBE switch combinations.
The DL T is divided into four quadrants. Each test condition (shown in the upper-left quadrant) is
reduced to a yes (Y) or no (N) result, as indicated in numbered columns of the upper-right quadrant,
two columns being allotted for each test condition. The two lower quadrants deal with recommended
actions.
2-69

To determine what actions (if any) should be executed for a given test result, follow the selected
column down to the number" 1" (first recommended action) in the lower-right quadrant. The specific
action to be taken is then located by following across to the lower-left (actions) quadrant. After action
1 has been taken, repeat the test that gave rise to the error condition. If the error persists, perform
action 2, test again, and so on. An "X" in the lower-right quadrant indicates a "no error" or a
"problem solved" situation, and requires no further remedial action.
Columns 12 through 20 (Table 2-16) define the sequential test that were alluded to in the second
paragraph of this procedure, and which should be made in an attempt to recover any data error. Note
that the last action item in any of these "yes" (even-numbered) columns instructs the operator to set up
the next condition, or test, for rereading the track in error. When the last of these sequential tests has
failed to recover the data, then and only then should the write flag procedure be carried out as indicated by action 3 of column 20.
2.7.4

Head Alignment Procedure

2.7.4.1 Installation of Head Alignment Card - This procedure describes the use of the type HFSV
head alignment card and the null meter on the FTU control panel to perform read/write and/or servohead alignment on the SMD under test. The cabling involved is seen in Figures 2-37 and 2-38 gives
specific connection information. The switches and indicators on the HFSV card are shown in Figure 237.
This procedure assumes that the I/O connections between the drive and the FTU have already been
made as described in the installation portion of this manual. The installation and cabling of the head
alignment card, must be made with ac power removed from the drive and the FTU.
1.

Install the proper CE pack on the drive to be tested.

2. Install the HFSV card in the drive's logic chassis at location A02.
3. Install the head alignment cable between the drive's logic chassis and the jack on the card in
the read/write (R/W) chassis, as specified in Figure 2-38. Note that PI04 is keyed so that it
will fit on the R/W card only one way.
4. Connect the test leads, provided with the FTU, between the HFSV card and the null meter
on the FTU panel. Observe polarity.
5. Set the WRT INHIBIT /NRM switch on the FTU to WRT INHIBIT.
6. Apply ac power to the drive. The POWER lamp on the HFSV card should light up.
7.

Power-up the drive.

8. Turn on the FTU. If the drive under test is in the write protect mode, the WRT PROT light
on the FTU panel will be lit.
9.

When the drive is up to speed and the READY light on the FTU panel is lit, actuate
RESET, then RTZ.

2-70

Pl04

INDICATORS
HEAD
SELECT/READ
~ J 104 AMPLIFIER CARD

HFSV CARD

A3A02
HEAD ALIGNMENT
CABLE

COMPONENT
SIDE OF
CARD

CONNECTS TO PINS
8 THROUGH 11

........

LOGIC CHASSIS
WIRE WRAP PINS

----~
l..._
A2 DISK DRIVE
LOGIC CHASSIS

FIELD TESTER

SCOPE

NOTE:
USE TOP SCALE o.F FIELD TESTER METER
IN CONJUNCTION WITH S3

S3 POSITION

FULL SCALE READING

-100 MVTO 100 MV
-1.0 V TO
1.0 V

X-l

MA-0613

Figure 2-37

Head Alignment Connections

2-71

HEAD ALIGNMENT CABLE
SMD
SERIES

HEAD ALIGNMENT
CARD LOCATION

CDC
BK5xx

A02

DEC
RM02
RM03

Pl041 0000

PLUGS INTO J 104 ON
HEAD SELECT/READ
AMPLIFIER CARD
IN RIW CHASSIS.

0000
~

SLIPS OVER WIW PINS
SA.B THROUGH 11 A.B
AT LOCATION RESERVED
FOR HEAD ALIGNMENT
CARD. A02

MA-0594

Figure 2-38

Head Alignment Card

10. Set the MAINT /NRM switch to MAINT. This provides a pseudo-index mark that enables
the FTU to generate a head select. (The CE pack does not have an index mark.)
NOTE
Installing the head alignment card (Table 2-17) automatically "write protects" the drive (even though it
will not of itself cause the WRT PROT light to come
on). Therefore, if write, write-then-read, or writeformat operations are to be conducted, the HFSV
card must first be removed from the drive.
2.7.4.2 Preliminaries for Head Check or Alignment - Before performing the head arm alignment
procedure, read and understand the concepts that follow. These are important for accurate head alignment, and they are only referenced in the procedure.
Thermal Stabilization - In order to ensure accuracy during head alignment, it is important that the
drive, CE pack, and FTU be at their normal operating temperature. This requires that all three be
connected and allowed to operate (pack turning and heads loaded to cylinder 0) for a minimum of 60
minutes. If head alignment is being performed on more than one drive, provided that the pack was
taken immediately from a previous drive and the drive under test has been operating with heads loaded
for a minimum of 60 minutes preceding test, the CE pack only requires IS-minute stabilization.
Write Protect - Although the presence of the head alignment card in the appropriate slot will write
protect the drive, the WRITE PROTECT switch on the front of the drive should be pushed in, as an
extra precaution.
Alignment Tool - Use only the head alignment tool specified in the maintenance tools and materials
table. Use of a different tool may cause damage to head-arm or carriage. Always inspect the adjustment end of tool prior to use. The tool must be free of nicks and scratches, and must have a polished
surface. If any aluminum deposits are present, polish the tool surface with crocus cloth. Any other
polishing medium will damage the tool. Do not use a defective tool; repair or replace the tool if
damage exists. When using the tool, position alignment tool so that pin in the end of the tool engages
the adjustment slot in the head arm. Ensure that the alignment tool is kept perpendicular to the hole in
the carriage at all times. The tool should turn freely in hole. If it doesn't, recheck the end of the tool for
damage or aluminum buildup.

2-72

Table 2-17

Head Alignment Card Switches and Indicators
Switches

Changes the polarity of the alignment signal to
the null meter; P = positive; N = negative. Algebraically subtract P from N to determine
alignment error: P = +30 mY; N = ~O mY;
Error = 70 mY.

S position selects servo head as input to HFSV.
RW position selects a data head as input to
HFSV.

Changes sensitivity of HFSV. The X.I position
attenuates card output by a factor of 10, and
alignment error cannot be accurately measured.
The XI position does not attenuate HFSV output; alignment error can be accurately measured.
Indicators

POWER

Lit when power is applied to the card.

INPUT

When lit, indicates that input signals are too low
for HFSV to operate.

BAD TRK

When lit, indicates a short duration loss of input. A one-shot keeps the LED lit for at least 4
seconds. The lamp will light when S I is toggled.

MODE

Lit when S2 is in the S (servo) position or when
S3 is set to X.I. When either of these conditions
exists, read/write head alignment error cannot
be measured.

Calculating Offset - The formula for calculating head offset is (P) - (N) = Offset, where P is equal to
the meter reading with the head alignment card P /N switch in the P position, and N is equal to the
reading with the switch in the N position. All meter readings to the left of 0 are negative. The following
are examples of offset calculation.

P = +20 m V, N = + 15 m V:
(P) - (N) = (+20) - (+15) = +5 mV

P = + 20 m V, N = -15 m V:
(P) - (N) = (+20) - (-15) = +35 mV

P = -20 mY, N = + 15 mY:
(P) - (N) = (-20) - (+ 15) = -35 m V

2-73

Seek Error Preventing - When the alignment tool is used to position the heads, a small amount of
sideways pressure on the tool can cause the carriage to move. This relatively minor amount of movement generates an error voltage which is sensed by the logic as a seek error. The end result is that the
logic clears the slope flip-flop and causes the drive to seek to the next even cylinder.
Excessive Misalignment - Occasionally, during the alignment check, a badly misaligned head(s) (in
excess of 200 mV offset) may be discovered. If this is so, the head(s) should not be realigned until all
packs written by that drive have been dumped (data transferred from pack to other storage). Failure to
dump the packs before realignment of the heads will mean that the data is not recoverable.
Carriage Locking - During the alignment procedure (when the heads are over the alignment track), the
carriage locking pin and ring assembly is installed in the ALIGN TRACK LOCK hole in the rail
bracket assembly. This locks the carriage in place. Failure to install the pin and ring assembly would
allow the carriage to retract if any emergency retract signal were generated. If the FE's hands are in the
actuator during the head alignment procedure, the retract could be dangerous. It should also be noted
that should a retract condition be generated, the carriage locking pin and ring assembly must be
immediately removed to allow the heads to retract before a head crash occurs. Carefully observe the
instructions regarding the installation and removal of the carriage locking pin and ring assembly.
NOTE
Do not do an RTZ on the FfU with the carriage
locking pin in the ALIGN TRACK LOCK hole.
CE Pack - The CE pack has odd-even dibits written on tracks 000 through 330 only, on the servo
surface. Do not attempt to access beyond track 330.
2.7.4.3 Head Alignment Check - The following procedure first checks the alignment of the servo head
and then checks the alignment of the read-write heads (which are aligned in relation to the servo head).
NOTE
Check that the rear shipping bracket is removed before attempting alignment and place the LOCAL/REM OTE switch in the LOCAL position.
Alignment instructions are provided if any head exceeds the allowable offset. The numbers specified
are decimal values for the cylinder address.
I. With heads fully retracted, raise logic chassis to m~intenance position and note position of
servo head adjustment slot in relation to hole in carriage. The adjustment slot should be
approximately centered in carriage alignment hole (Figure 2-39).
NOTE
If drive has been used to write data packs, servo head
should not be realigned until all read-write heads
have been checked and it is known that excessive misalignment does not exist on any of them. Refer to
step 1.

2-74

lOGIC CHASSIS
1B

REAR VIEW

BAPA09

UIl-----------~-~-1.

wI.li!.Dll

BAPA07~1.-============~/~/~/~/~/~/~/~/~/~/~/~/~/~BI~
.///////////// AJ
L

PA 80

BAPA03~~========~-/7/~/~/~/~/~/~/~/~/~B~I\\
I.!==:------/ / / A
/ / / / / / / / 1"'1/B"" / / / / 8B,/
B \\\\
////////11A

8A,/ A \\

Z~~~ P8
'j:O~ 'f:

\\
t-t

~
~

011
I '~1

~__~~--------------------------~
~O~~~
~--------------~~~- ... ~-.~
HEAD ALIGNMENT CABLE

SHROUD

~ ~~~6~
Pl04

HEAD ARM ASSEMBLY

READ AMPLIFIER
CARD A3A03

P8
8B
9B

PLUG PINS ON A02
BlK
RED
lOB GND
11 B WHT

MA-0640

Figure 2-39

Head Alignment Cable

2-75

If servo head is misaligned, loosen mounting screw and (using alignment tool) position
adjustment slot as shown in Figure 2-40. When servo head is properly positioned, tighten
head-mounting screw to a torque of 12 ± 1/2 inch-pounds. Lower logic chassis to normal
operating position.

NOTE
If servo head is adjusted, all read-write heads must be
adjusted.
3. With CE pack installed and oscilloscope connected to head alignment card test point Y,
load heads to cylinder 000 and perform thermal stabilization.
CAUTION
Do not attempt to access beyond cylinder 330.
4.

When thermal stabilization is completed, command continuous seeks between cylinders 240
and 245 for 30 seconds, minimum. This allows head-gimbal springs to settle to a normal
operating position, and also settles any binding between head arm and head-mounting
screw. Track 4 is a spare alignment servo track. The switch settings for cylinder 240 are 16,
32, and 128. For cylinder 245, they are 1,4, 16, 32, 64, and 128.

5. Stop continuous seeks and command a direct seek to cylinder 245.
6.

On head alignment card, set SjRW (servo/read write) switch to S position; set X.l/Xl
switch to X, 1 position,

Balanced dibit pattern, similar to Figure 2-41, should be observable on oscilloscope. If pattern is not balanced, terminate head arm alignment and perform trouble analysis.
NOTE
When calculating head offset, if both P and N readings are less than 100 mV, set X.l/Xl switch on head
alignment card to XI position. Return switch to X.I
position before proceeding to next head.

If balanced dibit pattern was observed in previous step, calculate head offset for servo head.
Servo head offset must be 0 ± 30 mY. If offset is greater than 30 mY, terminate procedure
and troubleshoot servo system.

9. On head alignment card, set SjRW switch to RW position. Select head O.

10. Calculate and record offset for head O.
11.

Repeat previous step for all remaining heads.
CAUTION
If any read-write head exceeded 200 mV offset, excessive misalignment exists. Refer to Step I and realign.

12. If calculated offset for any read-write head exceeded 100 mY, proceed to align heads. If all
heads were within the offset requirements, restore drive to normal operation.
2-76

SHIPPING
LOCK

TOP
COVER
DISK

PIN
STORAGE

RECORDING
SURFACE
NUMBER

0
1
2

4
BOTTOM
COVER
DISK

..,

HEAD
NUMBER

ISE~OI
4

MOUNTING
SCREW

HEAD/ARM

ALIGNMENT OF
SERVO HEAD
CARRIAGE
HOLE

CARRIAGE

~EAD/ARM

~A8JUSTMENT
HH
SLOT
Vo'STANCES
APPROX.
EQUAL
CAUTION
ALIGNMENT TOOLS ON SOME DRIVES
CANNOT BE ROTATED MORE THAN 150°.
ROTATING TOOL BEYOND 150° MAY
DAMAGE HEAD SLOT OR ALIGNMENT TOOL.
I\lA-0593

Figure 2-40

Head Arm Alignment
2-77

OSCILLOSCOPE SETTINGS
LOGIC GND TO SCOPE GND

VOLTS/DIV
CH 1- 2 V
CH 2 - NOT USED

CH 2

n , I n' I"I
"

I ,

TIME/DIV
A - 2 J.Lsec
B - NOT USED

U
CH 1

TRIGGERING
A - I NTERNAL POSITIVE
B - NOT USED
PROBE CONNECTIONS (USE X10 PROBE)
CH 1 TO ON HFSV CARD READ SIGNAL Y
CH 2 - NOT USED
MA-0606

Figure 2-41

2.7.4.4

Balanced Dibit Pattern

Performing Head Alignment

1. Ensure that the locking pin has been removed.
2. Command a return-to-zero seek. Press START switch to stop drive motor and unload
heads.
3.

Raise logic chassis to maintenance position and loosen head-mounting screw for any head
that exceeded the offset specification. Then retighten each loosened screw to a torque of 6
inch-pounds. Remove the connector support bracket from the head-arm connectors. This prevents possible electrical contact between the alignment tool and bracket. Contact could
cause a short circuit that would damage power amplifier.

Press START switch to start drive motor and load heads. Command continuous seeks between cylinders 240 and 245 for 30 seconds, minimum. Note that the MAINT /NRM switch
must be in the NRM position to do oscillating seeks.

5. Stop continuous seeks and command a direct seek to cylinder 245.
WARNING
Use care not to cause any short circuits when moving
logic chassis to install locking pin. Failure to install
locking pin could cause personal injury.

6. Swing down logic chassis and install carriage locking pin and ring assembly in ALIGN
TRACK LOCK hole. Return logic chassis to maintenance position.

2-78

7. Ground back panel pin A2B09, 03B (Not On Cylinder) to prevent nuisance errors. Ensure
that head alignment card X.l IXI switch is set to X.l position and select head to be aligned.
NOTE
The MAINT /NRM switch must be in the MAINT
position to select a different head. Place the
RD/WRT select switch to RD.
8.

Using recommended head alignment tool, (with the sleeving on it) perform coarse adjustment as follows.
a.

Adjust head until balanced dibit pattern is visible on oscilloscope.

Continue to adjust head for minimum deflection of null meter with respect to O.

While changing position of PIN switch, continue to adjust head until calculated offset
is less than 100 mV.
NOTE
If head cannot be aligned to less than 100 mY, it is
possible read-write head is at its end of tra\'eI. Recheck servo head alignment.

Repeat previous step for all heads to be aligned.

10. On head alignment card, set X.l IXI switch to Xl position.
11. Perform fine adjustment same as coarse adjustment except adjust until calculated offset is
less than 50 m V. Perform fine head adjustment for all heads to be aligned.
12. Remove ground from backpanel pin A2B09 03B.
13. Move carriage locking pin and ring assembly to PIN STORAGE hole.
14. Perform a return-to-zero seek.
15. For each head adjusted, tighten head-mounting screw to a torque of 12 ± 1/2 inch-pounds.
16. Command continuous seeks between cylinders 240 and 245 for 30 seconds, minimum.
17. Stop continuous seeks and command a direct seek to cylinder 245.
WARNING
Use care not to cause any short circuits when moving
logic chassis to install locking pin. Failure to install
locking pin could cause personal injury.
18. Swing down logic chassis and install carriage locking pin and ring assembly in ALIGN
TRACK LOCK hole. Return logic chassis to maintenance position.
19. Ensure that head alignment card X.l /XI switch is in Xl position.

2-79

20. Check alignment of each head that was adjusted to ensure that tightening screws did not
change alignment.
CAUTION
Use care when using alignment tool on heads that
have been tightened to torque of 12 ± 1/2 inchpounds. Misuse of tool will damage head arm or carriage.
21. If calculated offset for any head exceeds 75 mY, repeat fine adjustment procedure until
offset is less than 50 m V.
22. Move carriage locking pin and ring assembly to PIN STORAGE hole.
23. Restore drive to normal operation.
2.8

FIELD ACCEYfANCE PROCEDURE

2.8.1 Introduction
Field acceptance testing is intended to demonstrate the performance of the RM02 or RM03 disk drive
subsystem to the customer prior to his acceptance.
2.8.2 Error Definitions/Rates
The drive contains two registers to display the various error conditions possible. Error registers 1 and 2
(R MER 1, RMER2) indicate drive error conditions. One bit of RMER2 (SKI) indicates seek errors and
is used to calculate the seek error rate (Paragraph 2.8.2.4). Four bits of RMER 1 (HCRC, HCE, ECH,
and DCK, which may include DTE and FER) indicate data errors; the remaining bits' of RMER 1
indicate command and control errors. Table 2-18 lists indications of the various error types and theirexplanations.
2.8.2.1 Hard Errors - Any failure to read data correctly after a complete recovery sequence with ECC
enabled constitutes an irrecoverable, or hard, error. (A complete recovery sequence consists of 20
retries, 16 at the nominal head position and 2 at each offset.)
Errors that are not ECC-correctable include bursts greater than 11 bits in length and isolated dropped
bits (separated by more than 11 bits) within a sector. The allowable error rate for hard errors is one
error per 10 12 bits read.
2.8.2.2 Soft Errors - Any failure to read data correctly on the first try that is then read successfully
during a recovery sequence constitutes a recoverable, or soft, error. (Refer to the Paragraph 2.8.2.1
definition of a complete recovery sequence.) The allowable error rate for soft errors in one error per
10 10 bits read.
2.8.2.3 Pack-Attributable Errors - An error caused by imperfections in the recording surface is regarded as pack-attributable, or media-dependent. If the imperfection is less than 11 bits long, it is
EeC-correctable and will appear as a soft error; if more than 11 bits long, it will appear as a hard
error. On a given pack, pack-attributable errors will always appear at the same cylinder, sector, and
track addresses, with an ECC POS REG value within 11 bits. The definitions of hard and soft errors in
Paragraphs 2.8.2.1 and 2.8.2.2 apply only to randomly distributed errors, and do not take into account
errors that are pack-attributable. Imperfections in the pack surface may be found by mapping the pack
using the formatter program but there is no guarantee that they will all be found.

2-80

Table 2-18

Error Conditions

Bit

Bit Set
Register

Error
Type

HCE
HCRC

RMERI
RMERI

Soft

Sector count field/desired. Sector compare fails due to
CRC failure.

HCRC

RMERI

Soft

Sector count field matches desired sector field but there
is CRC error.

HCRC
FER

RMERI
RMERI

Soft

Format bit in first header word incorrect.

Explanation

NOTE
FER without HCRC during an operation that reads the
header indicates wrong format pack mounted.
DCK

RMERI

Soft

Error detected during read operation by examination
of ECC bytes; correctable by retry sequence.

DCK
ECH

RMERI
RMERI

Hard

Error detected which is ECC uncorrectable through 28
retry sequence (16 retries at nominal head position and
12 with head offset).

SKI

RMER2

Seek

I. Seek operation fails to complete within 500 ms of
initiation.
2. Recalibration operation fails to complete within 500
ms of initiation.
3. Offset or return-to-centerline operation fail.

SKI

RMER2

Seek

Positioner has drifted off cylinder subsequent to completion of positioning operation.

HCE

RMERI

Seek

Sector count field (RHLA) does not match desired sector field (RHDST) and there is not a CRC error. This
error is not caused by a positioner failure: It is due to a
DCL failure. Therefore, HCE alone indicates a drive
seek error.

2.8.2.4 Seek Errors - A seek error is any positioning operation that is not completed within 500 ms
for seek commands, 500 ms for recalibrate commands, and 10 ms for offset and return-to-centerline
commands, or that terminates with the positioner in an incorrect location. The allowable error rate for
seek errors is one error per 106 seek operations.
2.8.3 Field Acceptance Test
The tests described in Paragraph 2.8.4 may be used, individually or in combination, to demonstrate the
performance of the disk drive when used with an RH70 controller.

2-81

2.8.4 Diagnostic Programs
The diagnostic programs described herein are employed with the RM02 and RM03 subsystems. Refer
to the applicable diagnostic operation procedures for more detailed information.

Test Programs
MAINDEC-ZZ-CZRMF

Extended Drive Test

MAINDEC-ZZ-CZRMG

Dual-Port Logic Test, Part 1

MAINDEC-ZZ-CZRMH

Dual-Port Logic Test, Part 2

MAINDEC-ZZ-CZRMJ

RM02/03 Diskless Controller Test (only MBA test)

MAINDEC-ZZ-CZRMC

RM02/03 Functional Controller Test, Part I

MAINDEC-ZZ-CZRMD

RM02/03 Functional Controller Test, Part II

MAINDEC-ZZ-CZRME

RM02/03 Functional Controller Test, Part III (format the pack before doing Part III)

System Exerciser Program
MAINDEC-ZZ-CZRMB

Performance Exerciser (need formatted pack)

Utility Programs
MAINDEC-ZZ-CZRMA

Formatter Program (need good pack)

MAINDEC-ZZ-CZRMI

Drive Compatibility Test

2-82

CHAPTER 3
PARTS REMOVAL AND REPLACEMENT

NOTE
The following parts on the Recommended Spares
List (RSL) do not require any special removal and
replacement procedure.
Name

DEC Part No.

Circuit Breaker
Circuit Breaker
Thermostat
Varistor
Transformer (50 Hz)
Circuit Breaker (50 Hz)
Switch-mini
Circuit Breaker (50 Hz)
Hr Meter (50 Hz)
4 Mfd Capacitor
Line filter
Drm Capacitor (50 Hz)
6 Mfd Capacitor
Rail-lower
Rail-upper
Transformer
Line Filter
Lamp Assy (50 Hz)
21K Mfd Capacitor

12-13754
12-14167
12-14168
13-11996
29-22908
29-22918
29-22920
29-22921
29-22924
29-22927
29-22928
29-22937
29-22938
29-23028
29-23029
70-13785
70-13791
12-02556
29-22930

(60 Hz) 29-22907
(60 Hz) 29-22917
(60 Hz) 29-22922
(60 Hz) 29-22893
(60 Hz) 29-22923

(60 Hz) 12-01280

3.1 LOCATION OF OUTER SKINS
To gain access to the interior parts of the RM02 and RM03 Disk Subsystem, many of the outer skin
surfaces will have to be removed. These outer skins are shown in Figure 3-1. They are as follows:
•
•
•
•
•
•

Front door
Front bezel
Pack access cover
Drive top cover
Cabinet rear cover
Side panels.
NOTE
These removal procedures assume that the drive
power is off, the pack has been removed and the pack
access cover is open.
3-1

PACK ACCESS COVER

DRIVE TOP COVER

------?
FRONT
BEZEL

SIDE
PANEL

CABINET
REAR
COVER

MA-1300

Figure 3-1

Location of Outer Skins

3-2

3.2

FRONT DOOR

Removal Procedure: (Figure 3-2)
1.

Open the door.

Pull down on the spring loaded rod that hinges the top of the door.

Lift the door off its bottom pin.

Replacement Procedure:
1.

Mount the door on its bottom pivot pin.

Pull down the spring loaded rod on the top of the door hinge and lock the door in place.

Close the door.

PULL DOWN ON
SPRING LOADED
ROD TO REMOVE
FRONT DOOR
THEN LIFT OFF
BOnOM PIN

MA-0649

Figure 3-2

Front Door Removal

3-3

3.3 FRONT BEZEL
Removal Procedure:
NOTE
Power must be applied to the drive in order to raise
the pack access cover.
1.

Raise the pack access cover, then remove power.

Remove the two screws that secure the front bezel (Figure 3-3).

Lift the front bezel up and off its mounting brackets.

Replacement Procedure:
1.

With the pack access cover raised, place the front bezel onto its mounting brackets.

Secure the front bezel in place with the two screws.

FRONT
BEZEL
\"

BEZEL SCREWS
.A

.e.y ~

000

c:::::::I

ADAPTER

rt,
ANGLE
BRACKETS

MA-0650

Figure 3-3

Front Bezel Location

3-4

3.4 DRIVE TOP COVER
Removal Procedure:
1.

Loosen the two locking screws on the back of the top cover (Figure 3-4).

Slide the drive top cover back and then lift it off the rear of the drive.
CAUTION
Do not lift the cover until the guide pins are totally
disengaged.

Replacement Procedure:
1.

Place the top cover part way onto the drive.

Slide it forward into place.

Secure the drive top cover with the two locking screws.
DRIVE
TOP
COVER

MOUNTING
HARDWARE

CABINET
REAR
COVER

MA-1299

Figure 3-4

Drive Top Cover

3-5

3.5 CABINET REAR COVER
Removal Procedure:
1.

Loosen the two locking screws that hold the rear cover in place (Figure 3-5).

Lift the rear cover off its two holding pins.

Replacement Procedure:
1.

Mount the rear cover onto its two holding pins.

Secure the two locking screws that hold it in place.

B~~--------------i~B
~------eTO REMOVE REAR COVER:
1. LOOSEN LOCKING SCREWS (A).
2. LIFT REAR COVER OFF PINS (B).
MA-0651

Figure 3-5

Rear Cover Removal

3-6

3.6 SIDE PANELS
Removal Procedure:
l.

Remove rear cover for easier access to the side panels.

Remove the two mounting screws from the inside bracket shown in Figure 3-6.

Lift up the side panel to free the holding pins shown in Figure 3-6.

Pull the side panel outward and lift off.

A
TO REMOVE SIDE PANELS
REMOVE SCREWS AT LOATIONS (A)
AND LIFT PANEL UP. FREE PINS (B).
THEN PULL OUTWARDS.
MA-0646

Figure 3-6

Side Panel Mounting Screws

3-7

Replacement Procedure:
1.

Hold the side panel up to the side of the drive cabinet.

Line up the (B) mounting pins above their slots on the cabinet frame.

Lower the side panel so the holding pins lock into place.

Replace the two mounting screws on the inside bracket.

Replace rear cover.

3.7 PACK ACCESS COVER
The pack access cover is designed to lock when power is not applied to the drive. This makes it
necessary to apply power to up the drive before the pack access cover can be raised.
3.8 DECK MAINTENANCE POSITION
Many of the parts replacement procedures require raising the drive deck to its maintenanc~ position.
This position is illustrated in Figure 3-7. To raise the deck to the maintenance position, perform the
following steps.
1.

With power applied to the drive, raise the pack access cover up.

With the pack access cover in the open position, remove drive power.

Loosen the locking screws that hold the drive top cover in place, and slide it backwards off
the drive.

Install the rear deck hold-down spacer.

Remove the two top deck hold-down screws from inside the pack shroud area.

Raise the deck upwards until its support bracket locks into place.

Restoring the deck to the operating position:
1.

Hold the deck and unlock the support bracket.

Lower the deck carefully to its normal position.

Install the two deck hold-down screws inside the shroud.

Remove the rear hold-down spacer and install it in the keeper hole.

Slide the drive top cover into place and secure the two locking screws.

3-8

KEEPER HOLE

DECK
HOLDDOWN.
SCREWS

1
SHIPPING)
DECK
BRACKET
CASTING ( MOUNTS
HERE

DECK

SHOCK
~~~~~~--MOUNT

MA-0611

Figure 3-7

Deck Maintenance Position

3-9

3.9 POWER SUPPLY MODULES
There are three separate power supply modules in the power supply assembly shown in Figure 3-8.
AIAOI (± 42 V and emergency retract) (DEC Part No. 29-22878)
AIA02 (± 20 V and ± 12 V) (DEC Part No. 29-22879)
AIA03 (± 5 V) (DEC Part No. 29-22877)

(±5 V)
A1A03

WARNING PLATE

..;.......:...- CHASSIS MAP LABEL

EMERGENCY RETRACT RELAY

P1B

P100

MA-1522

Figure 3-8

Power Supply Assembly

3-10

Module Removal Procedure:
1.

Turn off power to the drive.

Remove the disk drive rear cover.

Remove the power supply cover.

Extract the desired module by lifting it straight up out of the chassis.

3.9.1 42 V Supply and Emergency Retract (AIA01)
There are no adjustments to be made on this board (DEC Part No. 29-22878) (Figure 3-9). Fuses Fl
and F2 are quick acting 8 A. Rl and R2 are fixed 510 ohm, 15 W, 10 percent resistors.

1:,---R3~P- $

CR7

~------------------~

•

- -

r'"'""!

MA1298

Figure 3-9

±42 Volt Supply

3-11

3.9.2 12 and 20 V Supply (AIA02)
There are no adjustments to be made on this board (DEC Part No. 29-22879). A board layout is shown
in Figure 3-10. Fuses Fl and F2 are quick acting 2 A.

A.......

- 1
,

VR2©!10

VR1@11

99C3

99C2

99C1

MA-1297

Figure 3-10

12 and 20 Volt Supply

3.9.3 5 V Supply (AIA03)
The adjustment procedure for the 5 V power supply (DEC Part No. 29-22877) is covered in Paragraph
4.2. Fuses Fl and F2 are quick acting 8 A (Figure 3-11).
3.10 BLOWER MOTOR ASSEMBLY (AIBM1)
Removal Procedure (DEC Part No. 29-22901,60 Hz, or Part No. 29-22902, 50 Hz) (Figure 3-12):
1.

Install the rear hold-down bracket.

Raise the deck to the maintenance position.

Remove the rubber collar from the blower assembly.

Remove J301 and 2 ground wires (black) and hot (yellow) wire from C5 (AI C5).

3-12

10
R20

~~¢¢

C13

--1 C10 I

{j9 {j-{ C12 ~
R12

v
....

......

a::
CD

a::

MA-1532

Figure 3-11

5 Volt Supply

3-13

RUBBER COLLAR

BLACK
LEADS
YELLOW
LEAD

BLOWER
MOTOR
CAP.
(A1C5)

MA-1525

Figure 3-12

Blower Motor Replacement

3-14

Remove the three hex nuts.

Remove blower, spacer, top bracket and squirrel cage.

Replacement Procedure:
1.

Install new blower, spacer, top bracket and squirrel cage.

Install the three hex nuts.

Reconnect J301 and the three faston connectors. The yellow wire connects to the (-) side and
the black wires connect to the (-) side of capcitor C5. The positive side ofC5 is indicated by
a red mark.

Install the rubber col1ar.

Lower the deck to its normal position.

Install the hold-down screws inside the shroud.

Remove the rear hold-down bracket and install it into the keeper hole.

3.11 PRIMARY FILTER
The primary filter (DEC Part No. 29-22926) must be kept clean in order to allow sufficient passage of
air to keep the drive cool.
Removal Procedure:
1.

Turn off power to the drive.

Remove front bezel.

Remove primary filter.

Replacement Procedure:
1.

Install primary filter.

Replace front bezel.

Restore power to the drive.

3.12 ABSOLUTE FILTER
An adequate supply of clean air to the pack area is essential to proper operation of the drive. Replacement of the absolute filter (DEC Part No. 29-22925) is required once every year.
Removal Procedure (Figure 3-13):
1.

Turn off power to the drive.

Install the rear hold-down spacer.

Raise the deck to the maintenance position.

3-15

ABSOLUTE

AIR
FILTER

BRACKET
MOUNTING

MA·1529

Figure 3-13

Absolute Filter Removal

Remove the front bezel from the brackets.

Remove the screw and lockwasher securing the absolute filter retaining bracket.

Remove the four screws holding the front bezel support brackets.

Remove the absolute filter bracket by pivoting it towards the front of the drive and lifting
the flange on the bracket from the slot in the base.

Remove the absolute filter by pulling it toward the front of the drive. It may be necessary to
jiggle the filter to disengage it from the blower motor outlet.

Wipe the base pan clean in the area under the absolute filter and around the blower motor
outlet.

3-16

Replacement Procedure:
l.

Install the new absolute filter by sliding it in from the front of the drive and engaging it in the
blower motor outlet.

Install the filter retaining bracket and secure it with a screw and lockwasher.

Install the front bezel support bracket with the four screws. Adjust the bracket for proper
mounting of the front bezel.

Lower the deck to its normal operating position and install the hold screws.

Install the front bezel.

Remove the rear hold-down spacer and install it in the keeper hole.

3.13 START TRIAC (AIKS)
The start triac (DEC Part No. 29-22929) cannot be repaired. If it fails, it must be replaced. The
location of the start triac is shown in Figure 3-14.
Removal Procedure:
1.

Turn off power to the drive.

Install the rear hold-down spacer.

Install the shipping lock on the heads.

Raise the deck to the maintenance position.

Remove all connectors from the start triac terminals.

Remove the two screws that hold the triac in place.

Replacement Procedure:
1.

Apply a light coat of dielectric grease to the base of the new triac.

Mount the new triac in place with the two screws, with the green wire attached to one of the
screws.

Reconnect all wires to its terminals according to Figure 3-14.

Return the deck to its operating position and install the mounting bolts in the shroud.

Remove the rear hold-down spacer and install it in the keeper hole.

Replace all skins.

3-17

START

~RIAC

/~
PIGGY BACK
SLIDE ON
CONNECTOR

SMALL DIA.
YELLOW WIRE

GREEN WIRE
UNDER SCREW
\

r:-\

SMALL DIA.
RED WIRE

4 - START- 3
TRIAC
0

2 - AIK5

LARGE RED
WIRE FROM
DRIVE CAPACITOR
(A3C6)

-~1

BLUE AND YELLOW
WIRES ON PIGGY
BACK CONNECTOR

MA-1515

Figure 3-14 Start Triac

3-18

3.14 RUN TRIAC (AIK1)
This procedure requires two people.
Removal Procedure (DEC Part No. 29-22929) (Figure 3-15):
1.

Remove the cabinet back cover.

Remove the two side panels.

Remove four drive hold-down screws fro111 the inside of the adapter enclosure.

Raise the deck to its maintenance position with rear hold-down spacer in place.

Remove the leads from the RUN TRIAC.

Apply a light coat of dielectric grease to the bottom of the new triac to be installed.

One person then pulls the drive backwards until the two Phillips head screws securing the
triac are visible.

The second person removes the screws from the old triac and installs the new one.

Push the drive back into position.

10.

Install the four drive hold-down screws that secure the drive to the cabinet.

11. Connect the leads to the new RUN TRIAC as in Figure 3-15.
12.

Restore the deck to its operating position and replace the hold-down screws.

13.

Remove the hold-down spacer and store it in the keeper hole.

14.

Replace all skins.

3.15 LOGIC CHASSIS ASSEMBLY (A2)
The most common repairs of the logic chassis are the changing of wires and the straightening of pins
on the wirewrap panel. For these procedures it is not necessary to remove the entire logic chassis.
Access to the wirewrap panel on the bottom of the logic chassis can be gained by raising the logic
chassis to its maintenance position and removing the bottom cover. If there is a broken pin, the logic
chassis must be replaced.
There is an old and a new version logic chassis assembly. The old style (series code 15) is illustrated in
Figure 3-16. The new style (series code 17) is illustrated in Figure 3-17.

3-19

YELLOW TO PIN 1
OF START TRIAC

LEAD

~\r---~

J1'
L

3
,,*

/.~--"-'

2 RED WIRES
IN HARNESS

RED WIRE
IN HARNESS

MA-1517

Figure 3-15

3-20

Run Triac

RIGHT
PANEL

FLAT
SPRING
LEFT
PANEL

MA-1526

Figure 3-16

Logic Chassis (Old)

3-21

LABEL

~,
LIP:
FITS INTO
KEEPER SLOT
HELD BY
TWO SCREWS

WIRE WRAP ASSY

I
fa

•
Figure 3-17

MA-1519

Logic Chassis (New)

3-22

Removal Procedure:
1.

Remove the drive top cover.

Disconnect the drive I/O cables from the logic chassis connectors.

Remove all cards from the logic chassis.

Raise the logic chassis to the maintenance position.

Remove the cover over the logic chassis wirewrap panel.

Remove all connectors and leads that would prevent the logic chassis from being lifted out.
NOTE
On the new style logic chassis, loosen (but do not
remove) the two screws holding the logic chassis lip
(Figure 3-17).

If this is a new style (code 17 and above) logic chassis, then perform steps 8 through 10. If
this is the old style (code 15) logic chassis then go to step 11.

Lower the logic chassis to its normal position.

Remove the two screws that hold it to the top of the magnetic housing.

10.

Remove the logic chassis from the drive.

11. With the logic chassis in the maintenance position, press in on the flat spring and siide the
logic chassis off its hinge.
Replacement Procedure:
1.

Install the logic chassis into the drive and secure it in place.

With the logic chassis raised to the maintenance position, reconnect all connectors and lead
to the bottom wirewra p panel.

Replace the cover over the wirewrap panel.

Lower the logic chassis to its operating position.

Return all cards to their proper location in the logic chassis.

Reconnect the drive I/O cables and tighten their cable clamp.

Make sure the logic chassis is returned to its operating position and then replace the drive
top cover.

3.16 CONTROL PANEL ASSEMBLY
Removal Procedure (DEC Part No. 29-22904):
l.

Remove the front bezel.

Raise the pack access cover.

Pop the control panel bezel off the deck assembly by pressing the metal tabs on the side of
the bezel (Figure 3-18).
CAUTION
Cable clearance going to PlOl is minimal.

Pull the control panel bezel forward a short distance using caution to avoid damaging the
cable.

Once the control panel bezel is extended just beyond the edge of the cabinet side panel, use a
screw driver in the opening next to the bezel ears to press the ears on the plastic control
panel inside (Figure 3-18).

Gently slide the control panel out of its bezel enclosure.

Unplug the cable and remove the control panel.

Replacement Proced ure:
1.

Assemble in reverse order.

3.17 POWER AMPLIFIER ASSEMBLY (A3A04)
Removal Procedure (DEC Part No. 29-22913) (Figure 3,-19):
1.

Remove the quick connect terminal (yellow lead wire) from faston on upper left hand corner
of assembly (Figure 3-19).

Loosen the hardware that secures the upper left hand corner of the power amplifier assembly, but do not remove it yet.

Remove connector J200.

Cut the tie wrap from the bottom right hand corner.

Remove the two sets of hardware that secure the assembly to the deck casting. An ofTseC''''
Phillips screwdriver will be needed.

Carefully lift assembly off.

Replacement Procedure:
1.

Assemble in reverse order.

3-24

/SHROUD

BEZEL EARS (2)

PLASTIC CONTRa L PANEL

J201

CONTROL PAN EL EARS (2)
MA-1512

Figure 3-18

Control P anel Assembly

3-25

SERVO PREAMP CARD

MOUNTING PLATE

PREAMP
HOUSING
POWER AMPLIFIER
(A3A04)
MA-1528

Figure 3-19

Power Amplifier

3.18 TRACK SERVO PREAMPLIFIER (A3A05)
Removal Procedure (DEC Part No. 29-22894) (Figure 3-19):
1.

Remove the attaching hardware on the upper left hand corner of the assembly. Carefully
slide the servo preamplifier shield out and let it hang on the servo head cable.

Unplug the servo head connector from the servo preamp board.

Raise the deck to the maintenance position.
3-26

Reach behind the servo preamplifier from under the deck and disconnect connector J8. It
may be necessary to cut and remove the cable tie wrap.

Remove the screw in the bottom left hand corner that secures the servo preamplifier housing
to its mounting plate.

Lower the deck.

Remove the hardware securing the servo preamp board to its housing.

Replacement Procedure:
1.
3.19

Assemble in reverse order. Note that the servo head connector is keyed.

DRIVE BELT

3.19.1 Adjustment
The drive belt (DEC Part No. 29-23110, 60 Hz; Part No. 9-23120, 50 Hz) adjustment may be performed any time there is suspicion that the belt may be slipping or as required by other procedures in
this manual. Before performing the adjustment, check the belt for any signs of damage: fraying, cracking, or checking of belt surface. If an} of these signs exist, replace the belt before performing adjustment.
1.

Raise the deck to the maintenance position.

Referring to Figure 3-20, measure the distance between the spring guide and stop nut. Distance must be:

•

Between 0.96 to l.12 cm (3/8 and 7/16 inch) for 50 Hz drives.

•

Between 0.48 to 0.8 cm (3/16 and 5/16 inch) for 60 Hz drives.

If the dimension is not correct, turn the motor adjusting rod until it meets specifications. A
ten inch screwdriver will be necessary to make this adjustment. It may also be necessary to
remove a cable clamp located in front of the adjusting rod.
CAUTION
If the adjusting rod is turned too far, the spring may
fall out of the spring guide.

Rotate the spindle while checking drive belt tracking. The belt must run true on both the
motor pulley and the spindle pulley. A failure to do so indicates a pulley misalignment.

When the belt is tracking properly, reinstall the cable clamp (if it was removed).

Return the deck to its normal operating position.

Apply power to the drive and press the START switch to start the drive motor. Remove the
side panel (Paragraph 3.6) and watch the drive belt to make sure it is tracking properly and
also that it does not slip.

3-27

j
./'

BRAKE ASSY.

SPRING
GUIDE

MOTl
SPRING

ADJUSTING
ROD

MA-1521

Figure 3-20 Drive Belt Adjustments
3-28

3.19.2
1.

Removal Procedure
Raise the deck (Figure 3-20) to the maintenance position.
CAUTION
Failure to relieve pressure on the compression spring
while removing the drive belt may cause the motor
shaft to bend.

Remove the cable clamp located in front of the adjustment rod to gain access to the belt
adjustment fixture.

Relieve the pressure on the compression spring by turning the adjustment out until pressure
is relieved. A long screwdriver will ease this process.

Remove the drive belt from the motor pulley by rolling the belt off while rotating the pUlley.
Disengage the belt from the spindle pulley and slip it out from around the brake.

3.19.3
1.

Replacement Procedure
Slide the drive belt up over the brake (but not onto the pulley) and then engage the other end
of the belt on the spindle pUlley.
NOTE
The smooth side of the belt goes in.

Apply tension to the belt and guide it onto the motor pulley while manually rotating drive
belt and drive motor pulley.

Manually rotate drive motor pulley several times to make certain that the drive belt is
tracking properly.

Perform the drive belt adjustment procedure.

Reinstall the cable clamp if it was removed.

3.20 DRIVE MOTOR AND BRAKE ASSEMBLY ADJUSTMENT (A3DM1, A3HB1)
There are two adjustments pertaining to the drive motor (DEC Part No. 29-231, 60 Hz, RM02; Part
No. 29-23122, 50 Hz, RM02; Part No. 29-22911,60 Hz, RM03; Part No. 29-22912,50 Hz, RM03) and
brake assemblies (DEC Part No. 29-22903): drive belt adjustment and brake adjustment. The drive
belt adjustment procedure is provided in the Paragraph 3.19. The brake adjustment is performed
during the replacement and is provided in the Removal-Replacement paragraph under brake replacement.
The brake assembly may be removed and replaced separately, or the drive motor and brake assemblies
may be removed and replaced as a unit. When removing the drive motor, the brake must also be
removed.

3-29

Removal Procedure
1.

Remove drive belt tension either by adjusting the motor adjusting rod or by applying
counter pressure to the drive motor brake assembly and pivoting it.

Remove the drive belt.

Remove tie wraps.

Disconnect the P303 drive brake plug.

Remove nut, spacer, and washer from the brake mounting bracket. Refer to Figure 3-21.

Loosen brake collar shaft Allen screw and remove the disk brake. Refer to Figure 3-21.

Remove four screws (three labeled "A", one labeled "B" in Figure 3-21) holding the motor
to the motor mounting plate. Note which screw has the grounding strap under it.

Disconnect P304.

Remove the drive motor and motor pulley assembly. Applying counter pressure to the drive
motor bracket against the tension spring may be necessary to obtain clearance for the top of
the motor.

10.

If the drive motor is replaced, also replace the drive motor capacitor A366.

Replacement Procedure
1.

Install the motor and pulley assembly using a slight rotation to clear the power cables.
Apply counter pressure on the drive motor bracket against the belt tension spring to clear
the top of the motor.

Connect P304.

Install three screws (labeled "A" in Figure 3-21) to hold the motor in place. Make sure
ground strap is under the correct screw.

Loosely install the brake mounting bracket with the fourth screw (labeled "B" in Figure 321). Note the position of the bracket in Figure 3-21.

Install the brake assembly onto the drive motor shaft in such a manner that its stud strikes
the end of the bracket slot.

Secure the Allen screw on its collar but do not snug up yet. This is the only adjustment to the
drive motor brake.

Install the nut, spacer, and washer on the drive break mounting assembly and tighten.

Tighten the brake mounting bracket and motor with an offset Allen wrench.

Tighten the Allen screw from step number 6 on the brake collar to 30 ± 2 in-lb.

10.

Reconnect P303 drive brake plug.

3-30

MOTOR~

MA-1513

Figure 3-21

Drive Motor and Brake Assembly

3-31

11.

Replace cable ties.

12.

Make sure motor and brake assembly are free to pivot so belt tension will be maintained
when the disk drive is operating.

13.

Reinstall the drive belt and proceed to belt tension procedure.

3.21

SPINDLE ASSEMBLY

3.21.1 Adjustment
Spindle adjustment (DEC Part No. 29-22900) must be performed any time the attaching hardware
securing the spindle to the deck has been loosened.
1.

Open the pack cover.

Remove head arm assembly numbers 3 and 4. Refer to head assembly removal procedures in
Paragraph 3.32.

Install carriage alignment arm in the slot on carriage just vacated by head arm assembly
number 3. Secure the alignment arm to the carriage and tighten its attaching screw to a
torque of 4 in-lb.

Extend the carriage until the alignment arm is aligned as shown in Figure 3-22.

U sing the attached nonmetallic feeler gauge, check that the distance between the alignment
arm and the spindle is 0.0077 ± 0.0025 cm (0.003 ± 0.001 inches) as shown in Figure 3-22. If
adjustment is required, go to step 6. If the specification is met, go to step 15.

Raise the deck to its maintenance position after installing rear holding bracket.

Remove the drive belt.

Lower the deck to its normal position.

Retract the carriage and rotate the spindle until the holes in the top of the spindle line-up
with the spindle mounting screws.

10.

Loosen the screws and washers that secure the spindle to the deck.

11.

Extend the carriage until the alignment arm is positioned as shown in Figure 3-22.

12.

Using a plastic faced hammer, gently tap the spindle until the dimensions between the alignment arm and the spindle are as specified.

13.

Tighten one screw at a time and check the dimension after each one.

14.

When the spindle alignment specifications are met, raise the deck and replace the drive belt.
Then return the deck to its operating position and secure it. Remove the rear hold-down
bracket.

15.

Remove the alignment arm and install head arm assemblies 3 and 4 back into the carriage. A
slight upward force on the heads as the head arm reaches the ramp area allows for easy
insertion.

3-32

CARRIAGE
ALIGNMENT
ARM

MEASUREMENT
FACE

~~~~~E

HOLES FOR REMOVING...........;;==~
SPINDLE-TO-DECK
0.003 ± .001 INCHES
MOUNTING SCREWS
MA-1296

Figure 3-22

Spindle to Carriage Alignment

3.21.2 Removal Procedure
This procedure covers removing the spindle assembly. Note that it is not necessary to remove the
spindle to perform lockshaft replacement.
1.

Insert the rear hold-down bracket.

Raise the deck to its maintenance position.

Remove the hardware that secures the ground cable to the static ground spring block (Figure 3-24). Be careful not to lose the two star washers.

Remove the drive belt.

Lower the deck to its normal operating position.

3-33

Rotate the spindle until the holes in the top of the spindle line up with the mounting hardware.

Remove the three Allen head screws that secure the spindle assembly to the deck.
CAUTION
Never rest the spindle assembly down on its pulley
end. Lay it either on its side or on the face plate.

Lift the spindle assembly from the deck being very careful not to damage the static ground
spring.

Remove the ground spring mounting block and assembly from the spindle assembly.

3.21.3

Replacement Procedure

Install the static ground spring assembly onto the new spindle assembly.

Carefully lower the replacement spindle assembly through the deck opening in the shroud.
Orient the spindle assembly so that the ground spring mounting block faces the drive motor.

Secure the spindle assembly to the deck with the mounting screws.

Perform the spindle adjustment procedure.

When spindle adjustment is complete, install the ground cable to the static ground spring.

Install the drive belt and perform the belt adjustment procedure.

Check the speed sensor adjustment.

Remember to install the rear hold-down spacer into its keeper hole after the deck is secured
back into its operating position.

3.22 SPINDLE LOCKSHAFT REPAIR
Repair of the spindle assembly is limited to removal and replacement of the lockshaft and associated
hardware as indicated in the parts data section. The following procedure covers removal and replacement of the lockshaft.
1.

Raise the deck to maintenance position after the rear hold-down bracket is installed.

Referring to Figure 3-24, remove attaching hardware securing ground cable to static ground
spring block.

Remove static ground spring from mounting block.

Remove shaft end seal by prying down with a pair of opposing screwdrivers.

Reaching in from bottom of spindle, remove shoulder screw and associated washers and
spring. Spindle may be locked in position during shoulder screw removal, by pressing down
on end of brake plate.

Lift lockshaft out from top of spindle.

3-34

Install replacement lockshaft, sliding it in from top of spindle. If smaller compression spring
came out with old lockshaft, assemble it on new locks haft before assembly.

Assemble two washers and compression spring on shoulder screw as shown in Figure 3-23.
Apply a thin coat of Loctite primer, grade T, to last four threads of shoulder screw; being
careful not to get any primer on spring or washers.

SOCKET HEAD SCREW"

LOCK WASHER ____________

i
~
I

I
LOCKSHAFT
~ COMPRESSION
~
SPRING

LOCKSHAFT
WASHER

COMPRESSION
_ _ _ _ _ _ _ _ _ _ SPRING

LOCKSHAFT
____________ WASHER

~
I

____________

SHOULDER
SCREW

SHAFT
END SEAL

MA-1511

Figure 3-23

Spindle Assembly

3-35

Allow Loctite primer to air dry for approximately five minutes.

10.

When Loctite primer is dry apply a thin coat of Loctite, grade C, to last four threads of
shoulder screw. Parts must be assembled within three minutes of Loctite application.

11.

Assemble shoulder screw and hardware into bottom of lockshaft. Tighten shoulder screw to
a torque of 40 ±5 in-lb.

12.

Press shaft end seal into position on bottom of spindle assembly. Lower deck to normal
operating position and allow Loctite to air dry for approximately three hours.

13.

Following Loctite cure, raise deck to maintenance position and assemble static ground
spring and associated ground cable.

14.

Perform clean and lubricate locks haft procedure.

15.

Perform static ground spring adjustment procedure.
CAUTION
Replace the rear hold-down spacer into its keeper
hole after the deck is restored to its operating position.

3.23 STATIC GROUND SPRING ADJUSTMENT
The ground spring adjustment procedure (Figure 3-24) must be performed any time the screws securing the spring or mounting block have been loosened.
1.

Install the rear hold-down bracket.

Raise the deck to its maintenance position.

Remove the hardware that secures the ground cable to the ground spring mounting block
and disconnect the ground cable.

Connect a multimeter (set to RXl) between the ground cable and the ground spring. The
meter should read zero ohms. If not, go to step 5. Otherwise, proceed to step 6.

Clean the bottom of the shaft end seal (on the bottom of spindle) using a piece of gauze
slightly dampened with media cleaning solution. Repeat step 4.

Disconnect the m ultimeter and connect the ground cable to the ground spring mounting
block.

Ensure the ground spring is tight enough to eliminate any bounce.

Secure the deck in its normal operating position.

Replace the rear hold-down bracket in its keeper hole.

3-36

SPRING
HOLDER
SCREW

PAN HEAD

GROUND
CABLE

Jlt"' '

,,' ~"

6-32 X 5/8""

:-~/&
.. &
~

(~e

'"
GROUND
SPRING

(3) PAN HEAD SCREWS

6-32 X 3/8

SPINDLE PULLEY

STATIC GROUND
SPRING

MA-1510

Figure 3-24

Static Ground Spring

3-37

3.24 SPEED TRANSDUCER (A3Ll)
3.24.1 Adjustment
Speed transducer (DEC Part No. 29-22909) adjustment is required whenever the relative position of
the spindle and the speed transducer has changed, or as required by other procedures in this manual.
1.

Place the Go-No Go tool across the top of the spindle face plate so that the gauge extends
out over the top of the speed transducer. Refer to Figure 3-25.

Check the dimension from the top of the speed transducer to the top of the spindle face plate
as shown in Figure 3-25. This dimension should be 1.2224 ± 0.0026 cm (0.4775 ± 0.0010 in).
If adjustment is required, proceed to step 3. If no adjustment is required, go to next adjustment.

Install the rear hold-down bracket and then raise the deck to the maintenance position.

Loosen the locknut on the bottom of the speed transducer. Disconnect connector J202 so
that the transducer leads are free to turn during adjustment.

Rotate the speed transducer until its top makes contact with the Go surface of the GoNoGo tool. Tighten the locknut with caution since the housing is made of plastic.

Recheck the dimension with the Go-NoGo tool.

When the dimension is correct and the locknut is tightened, install connector J202.

Return the deck to the normal operating position and install the rear hold-down bracket
back into its keeper hole.

3.24.2

Removal Procedure

Install the rear hold-down bracket and raise the deck to the maintenance position.

Disconnect connector J202.

Remove the locknut on the bottom of the speed transducer and remove the transducer from
the deck opening.

3.24.3

Replacement Procedure

Install the new speed transducer into the deck opening.

Secure the transducer loosely in place with its locknut using caution not to damage the
plastic housing.

Perform the speed transducer adjustment procedure.

Secure the deck in its operating position and make sure that the rear hold-down spacer is
installed back into its keeper hole.

3-38

0.4775 ± 0.0010
JUST TOUCHING
O-NOGO TOOL

LOCKNUT

SPEED
TRANSDUCER

DECK

SPINDLE

MA-1S09

Figure 3-25

Speed Transducer Adjustment

3.25 VELOCITY TRANSDUCER (A3L2) REMOVAL AND REPLACEMENT PROCEDURE
The velocity transducer assembly (DEC Part No. 29-22906) consists of a transducer coil (complete
with housing and connector).
NOTE
The coil and rod come together as a single item, and
must be replaced as such.

Remove the hardware securing the transducer coil to the rear of the magnet assembly. Unplug connector P22 (Figure 3-26).

Carefully remove the transducer coil, sliding it straight out of the rear of the magnet assembly.

Slowly and carefully slide the replacement transducer coil into the rear of the magnet assembly.

3-39

MAGNET

TRANSDUCER CORE

EXTENSION ROD
MA·1523

Figure 3-26

Velocity Transducer Replacement

Align one of the three slots on the back of the transducer coil with the mounting hole in the
magnet. Manually extend the heads and slide the carriage back and forth. Be aware of any
drag or rubbing sound. Rotate the coil and move the carriage again for each of the remaining two slots on the back of the transducer coil.

Select the mounting slot which produced the least drag or rubbing. Orient this slot toward
the mounting hole and install and tighten the attaching hardware.

Connect connector P22. Extend the heads and move the carriage back and forth to verify the
alignment of the transducer coil.

3.26 PACK COVER SOLENOID (A3L3) ADJUSTMENT
There are two versions of the pack cover solenoid assembly (Figure 3-27). There is an old style that
exists on the early drives, and a new style that is used on the DEC customized drives.
3.26.1 Old Style Solenoid Adjustment
The pack cover solenoid adjustment is required whenever the solenoid is changed or if the pack cover
does not lock when power is removed from the drive. There are two adjustments pertaining to the
solenoid: clearance, and spring tension.

3-40

INTERLOCK
LATCH

SPRING TENSION
ADJUSTM ENT SLOT
(A)

SOLENOID

OLD STYLE SOLENOID

(B)

NEW STYLE SOLENOID
MA-1527

Figure 3-27

Pack Cover Solenoid Adjustment

The clearance adjustment is made to obtain minimum clearance between the interlock latch (refer to
Figure 3-27) and the interlock keeper on the pack access cover. When the pack access cover is latched
(solenoid deenergized, and latch in up position) the keeper must strike the latch and not allow the pack
cover catch to be released. Loosen the attaching hardware securing the solenoid assembly to the
shroud, and slide the assembly backwards or forwards to achieve this adjustment.
The spring tension adjustment is made to fully extend the solenoid plunger when the solenoid is
deenergized. The tension should not be so great as to prevent the plunger from fully retracting when
the solenoid is energized. Perform the adjustment by loosening the spring mounting hardware and
sliding it up or down in the mounting slot.

3-41

3.26.2

New Style Solenoid Adjustment

Raise the deck to the maintenance position after the rear hold-down bracket is installed.

Loosen the mounting screws securing the solenoid assembly to the shroud.

Close the pack cover.

Slide the solenoid assembly backwards until the latch engages the strike plate.

Hold the solenoid in this position and tighten the mounting screws.

Lower the deck and return rear hold-down bracket to its keeper hole.

3.27 RAIL BRACKET ASSEMBLY
Only specially trained and qualified field service personnel should make adjustments to the rail bracket
assembly (Figure 3-28), or attempt to replace it. These procedures require special tools and great
precision and should not be attempted by untrained personnel.
Under no circumstances should the screws securing the rails or the rail bracket to the deck be loosened.
If either the rails or the rail bracket assembly are damaged or misaligned, contact the nearest Regional
Support Center.

CAM TOWER
MA-1508

Figure 3-28

Rail Bracket Assembly

3-42

3.28 CARRIAGE AND COIL ASSEMBLY
Only properly trained personnel with the special tools needed, should attempt the alignment procedure
for the carriage and coil assembly (DEC Part No. 29-22910). The precision alignment of the carriage
bearings makes this process difficult. The carriage and coil assembly is illustrated in Figure 3-29.
CARRIAGE AND
COILASSEMBLY

FLEX LEAD
ASSEMBLY

FLEX LEAD
RETAINER

~~~

FLEX LEAD

MA-1520

Figure 3-29

Carriage and Coil Assembly

3.29 FLEX LEAD ASSEMBLY ADJUSTMENT
Adjust the flex lead assembly (DEC Part No. 29-22905) (Figure 3-29) any time the assembly is
changed. Adjustment of the flex lead assembly is a matter of positioning the assembly so that it is
parallel with the travel of the carriage and coil assembly. When the flex lead assembly is properly
aligned, there is no buckling of the leads during extension and retraction of the carriage and coil
assembly.
3.30 HEADS LOAD SWITCH (A3S2) ADJUSTMENT
Perform the heads loaded switch adjustment (Figure 3-30) under any of the following conditions
•

Heads do not fully retract when drive is powered down.

•

Unknown cause of a power amplifier or power amplifier fuse failure.

•

Heads loaded switch is changed or in any way moved.

•

Instructed to do so by another procedure.

3-43

NORMALLY
OPEN

MA-1518

Figure 3-30

Head Loaded Switch Replacement

To adjust the heads load switch, complete the following steps.
1.

Disconnect leadwires from heads 10 aded switch, taking note of leadwire placement.

Connect multimeter (set to RX1 scale) between ground contact and normally open contact
as shown in Figure 3-30. With carriage fully retracted, multimeter should indicate zero
ohms.
NOTE
Measure carriage travel between rear edge of voice
coil and inside back edge of magnet assembly.

Note measurement from rear of voice coil to inside back edge of magnet assembly with
carriage retracted. Manually extend heads very slowly, while observing multimeter. Measure
carriage travel at point that multi meter switches from zero ohms to infinity. Difference
between fully retracted measurement and heads extended measurement should be 0.125 to
0.1875 inch.

If switch does not transfer within specified measurement, loosen hardware securing switch
mounting bracket to rail bracket assembly and adjust switch position.

When adjustment is complete recheck carriage travel per step 3. Assuming adjustment is
correct, reconnect leadwire to heads loaded switch.

3-44

3.31 MAGNET ASSEMBLY ADJUSTMENT
The magnet assembly (DEC Part No. 29-22874) (Figure 3~31) must be adjusted any time the mounting
hardware securing the magnet to the deck is loosened.
LOGIC CHASSIS
MOUNTING BRACKET

SLIDE BRACKET

/
MAGN ET COVER

MA-1530

Figure 3-31

Magnet Assembly
3-45

The magnet assembly is properly adjusted when the coil slides through its complete travel without
contacting the magnet assembly. Ensure that when the magnet assembly is secured to the deck, a 0.005
inch nonmetallic feeler gauge passes between the coil and the magnet. The 0.005 inch clearance must be
maintained at all points around the coil in the front opening of the magnet assembly. After securing
the magnet to the deck, and before installing the velocity transducer, manually extend the heads and
move the carriage and coil assembly back and forth through its full travel. There should be no rubbing
or scraping sound and there should be no drag felt during this movement.
3.31.1 Removal/Replacement Procedure
When removing the magnet assembly the hinge for the logic card cage assembly will have to be removed from the magnet housing.
CAUTION
Be sure that when the assembly is removed and re-

placed, the housing does not hit or damage the carriage and coil assembly.
3.32 HEAD ARM ASSEMBLY
Refer to Chapter 1, Paragraph 1.2.3 for part numbers.
3.32.1 Repair
The drive has a positive pressure filtration system that eliminates the need for periodic inspection and
cleaning of heads. The heads should be inspected for the following reasons only:
1.

A problem is traced to a specific head or heads; for example, excessive data errors.

Head to disk contact is suspected. This may be indicated by an audible ping, scratching
noise, or a burning odor when the heads are over the disk area.

Concentric scratches are observed on the disk surfaces.

Contamination of pack is suspected (possibly due to improper storage of the pack).

The pack has been physically damaged (possibly due to dropping or bumping).
CAUTION
Do not attempt to operate the media on another drive
until full assurance is made that no damage or contamination has occurred to the media.
Do not attempt to operate the drive with another
media until full assurance is made that no damage or
contamination has occurred to the drive heads or to
the shroud area.

3-46

3.32.2

Head Inspection
CAUTION
Do not smoke when inspecting or cleaning heads.
Use extreme care not to damage the head.
Do not touch the head pad or gimbal spring with fingers or tools.
If head must be laid down, do not allow the head pad
or gimbal spring to touch anything.

Remove suspected head as described in the Read/Write Servo Head/Arm Replacement pro..cedure.
Observe the head/arm, and perform the suggested remedy as follows:
1.

If reddish-brown oxide deposits exist on the head, replace or clean the head/arm assembly.

If head appears scratched, replace or clean the head/arm assembly.

If head appears damaged, replace the head/arm assembly.

If the gimbal spring (holding the head pad to the arm) is bent or damaged, replace the
head/arm assembly.

Heau Clt:aning
CAUTION
Head cleaning is a delicate procedure which is not
recommended. It should not be undertaken unless it
is absolutely necessary and then it should be performed by properly trained personnel only.
Head Replacement Procedure
The following procedure covers removal and replacement of either the servo head or the read/write
heads. Remove heads from the carriage only to perform head inspection and cleaning, or as directed
by other procedures in this manual. When removing the servo head also remove read/write head
number two. This allows room for the head cable and connectors to pass between the adjacent head
arms with a lessened chance of doing damage.
1.

Remove connector support bracket or servo pre-amplifier shield and disconnect head arm
connector for subject head (for servo head, also remove head cable from cable clip and
disconnect tie point connector). Refer to Figure 3-32.

Remove head mounting screw and associated hardware.

3-47

HEAD SELECT AND
READ PREAMP BOARD

ONLY ONE HEAD/ARM SHOWN
MA-1516

Figure 3-32

Head Replacement - Left Side View

Manually extend heads far enough to be able to grasp front of head arm from inside pack
area.
CAUTION
Head pads and gimbal springs are extremely delicate
and easily damaged. Grasp head arms carefully and
only by edges of head arm if head pad is touched,
perform head cleaning procedure.

Grasp entire stack of heads such that they are all held in alignment to one another. Carefully
extend heads all the way into pack area.

Carefully grasp subject head arm at front and also push gently on rear of head arm as shown
in Figure 3-33. Guide head arm and connector(s) through adjacent head arms and into pack
area.

Perform required maintenance procedure.

3-48

REAR
NOTCH

HEAD/ARM
CONNECTOR

CABl
CLIP

DECK

HEAD
CABLE

Figure 3-33

MA-1524

Head Replacement - Right Side View

Install head arm assembly by fully extending heads into pack area, and guiding head arm
connector between adjacent head arms. Use care not to damage adjacent heads.

Seat head arm in both front and rear notches on carriage.

Grasp entire stack of heads such that they are all held in alignment to one another. Carefully
retract heads. Do not push on front of head arm assemblies while retracting heads.

10.

Carefully position head arm as required in order to insert head mounting screw. Support
head arm from opposite side when inserting head mounting screw or forward pressure of
wrench may dislodge head arm.

11.

Ensure that head arm assembly is aligned in relation to remainder of heads where they
protrude into pack area.

12.

Tighten screw, securing head arm assembly to carriage, until torque is 12 ± 1/2 in-lb.

13.

Carefully reconnect head arm connector and replace related hardware removed in step 1.

14.

Perform Head Arm Adjustment procedure, described in Chapter 2.
3-49

CHAPTER 4
ADJUSTMENT PROCEDURES

4.1 VELOCITY GAIN ADJUSTMENT WITH FTU
This procedure provides information on the checking and, if necessary, adjusting of the servo system
velocity signal. If the adjustment cannot be completed satisfactorily, the procedure must be terminated. If this happens, perform trouble analysis. The following procedure assumes that the FTU is
connected, and that a scratch pack is installed on the drive.
1.

With the drive case closed, command random seeks for 10 minutes minimum in order to
thermally stabilize drive.

Stop random seeks and set up oscilloscope per Figure 4-1. Oscilloscope ground references
must be as shown.

Command 822 cylinder continuous seeks and adjust oscilloscope trigger level to obtain
waveform shown in Figure 4-1.

Measure full length seek time. Time between On Cylinder pulses should be 52 to 54 milliseconds.

If full length seek time is not as specified, perform velocity gain adjustment. On card A2A07,
adjust velocity gain potentiometer E2R6 (Figure 4-2) until time between leading edges of On
Cylinder pulses is 52 to 54 milliseconds. Use a No. 50 Allen wrench (0.127 cm or 0.050 in).

Return drive to normal operation.
NOTE
Head alignment is detailed in Chapter 2.

4.2 GENERAL VOLTAGE ADJUSTMENTS
This procedure checks the output of the plus and minus dc power supplies while the drive is doing
repetitive seeks. Either the Field Tester Unit or the extended drive diagnostic may be used to perform
the repetitive seek operation.
CAUTION
Drive should not be operated for extended period
with logic chassis in maintenance position. Loss of
cooling air (when logic chassis is raised) could cause
drive to overheat.
1.

Remove the rear cover from the drive.

Loosen (but do not remove) the two screws on top of the front card cage area.

4-1

FULL LENGTH
SEEK TIME
i-

-4V
-GND

ascI LLOSCO PE SETU P
VOLTS/DIV

TEST POINT

SIGNALNAME

CH 1(USE X10 PROBE)

0.2 V

A2B0903A

+ ON CYLINDER

CH 2(USE X

NOT USED

SLOPE/SOURCE

TEST POINT

SIGNAL NAME

TRIGGER A (USE X10 PROBE)

+/EXT

A2B0907A

- FORWARD
SEEK

TRIGGER BPROBE)
(USE X

NOT USED

PROBE)

TIME/DIV: 10 ms

MODE TRIGGER: CH 1

ADDITIONAL SETIINGS:

NONE
MA·1294

Figure 4-1

Velocity Gain Waveform

4-2

OC'(W+R)
A04CR5
R'W
A04CR4
VELOCITY

HDSEL\
A04CR3

A04CR1

MAINT FAULT
CLEAR
CLEAR NORM
MA-1514

Figure 4-2

Velocity Gain Adjustment

4-3

Loosen the rear hold-down screw on the bottom of the card cage.

Raise the card cage to its service position by sliding it back and lifting it up and over on its
side.

Using a digital volt/ohmmeter, the following dc voltage levels can be measured (Figure 4-3).
a.
b.
c.
d.

±5 V (±0.05 V) on faston connectors
±20 V (± 1.0 V) on faston connectors
±42 V (±2.0 V) at Pin 32B, -42 V (±2.0 V) at Pin 3B, on connector PA09
± 12 V (±0.3 V) at Pin 8B, -12 Volts (± 0.3 V) at Pin 8A, on connector PA80

lOGIC CHASSIS
REAR VIEW

~_~~~~~~PI!

BAPA09/1
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PA 80

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t-t

READ AMPLIFIER
CARD A3A03

~~·!iE04

P104
HEAD ARM ASSEMBLY

PLUG PINS
ONA02
8B
BlK
98
RED
10B GND
11 B WHT

MA-0640

Figure 4-3

Power Supply Test Pins

4-4

Command the drive to do repetitive seeks between cylinders 0 and 32.

The +5 V output should read +5.10 ±0.05 V. Ifnot, adjust the +5 V potentiometer on card
A lA3 (Figure 4-4) until it is within specification. Use a No. 50 Allen wrench.

Move the volt/ohmmeter leads to -5 V faston.

-5 V output should read -5.10 ± .05 V. If not, adjust the -5 V potentiometer on card Al A3
(Figure 4-4) until it is within specification. Use a No. 50 Allen wrench.

10.

If any adjustment was necessary in the preceeding steps, recheck both outputs.

11.

When both power supply outputs are within specification, restore the drive to normal operation.

A1A3

+5 V ADJUSTMENT

MA-1531

Figure 4-4

5 Volt Adjustments

4-5

CHAPTER 5
FAULT ISOLATION

5.1

USING THE FAULT ISOLATION GUIDES

5.1.1

Introduction

This chapter contains the Fault Isolation Guides (FIGs) that are designed to enable service personnel
to troubleshoot the RM02 or RM03 Disk Drive to the Field Replaceable Unit (FRU). The maintenance philosophy for this drive is for the service personnel to replace a defective FRU without attempting to repair it.
The first portion of this chapter, Paragraph 5.1, "Using the Fault Isolation Guides", describes how to
u~e the FIGs as a troubleshooting tool. Paragraph 5.1.2 contains some general safety tips and other
important information. Paragraph 5.1.3 describes how to determine which portion of the subsystem
(either drive, adapter or RH controller) is defective. Paragraph 5.1.4 describes the use of the FIGs in
more detail. including a list of test points and a flow diagram to point the service personnel to the
correct FIG for a specific condition. Paragraphs 5.2, 5.3, 5.4, and 5.5 contain the actual Fault Isolation
Guides, and Paragraph 5.6 contains some information on advanced troubleshooting techniques for the
RM02 or RM03 Disk Drive.

5.1.2

General Information

The following paragraphs contain information needed to correctly employ the Fault Isolation Guides.

5.1.2.1

Safety - The following is a list of safety-related hints and tips to be aware of while troubleshooting and servicing the RM02/03 Disk Drive.
1.

Turning capacitor Al C8 to 440 V. Treat it with respect (Figure 5-1). After shutting off the
circuit breaker it is advisable to short out the capacitor several times with the side of a
screwdriver blade.

If the fault LEDs on A2A04 do not momentarily flicker when CB2 is turned off there may
not be any +5 V. The voice coil can burn out if the power supplies are left on with +5 V
being present. Therefore, turn off CB2 and verify the +5 V supply before burning out the
voice coil.

Keep all watches, disk packs, meters, and other test equipment at least 2 feet away from
voice coil magnet.

Power supply fuse ratings are as follows:
±5V
±20V
±42V
±12V

8 A fuse
2 A fuse
6 A fuse
current limiting resistors (51 nat 10 W).

5-1

A2Al0
A2AOl

A3AOl
(P201)

A1Ml

~A1CBl
~A1CB2

A 1 FL 1

MA-1901

Figure 5-1

Physical LocafIon Codes

5-2

Line voltages are present inside the base (A 1) in the area of the ac power supply (Figure 5-1).

Do not remove or install circuit cards while power is on. They can be damaged by the
transient voltages that occur.

If the drive fails to power down when the start switch is pressed (to turn off indicator),
disconnect the voice coilleadwire and manually retract the heads before troubleshooting the
malfunction.

When manually loading heads, move the carriage swiftly (7 inches/second) into the pack
until the heads come off the cam towers and the heads are in the guard band zone. Once
loaded in the guard band, slow changes to carriage position are advisable. This procedure
will prevent head and disk pack damage.

When manually unloading heads move the carriage off the guard band area to the rear crash
stop swiftly (7 inches/second.) This procedure will prevent head and disk pack damage.

10.

If power to drive motor is lost while heads are loaded and not under servo control (during
manual carriage positioning), immediately retract carriage. Otherwise heads will crash when
disk speed is insufficient to enable heads to fly.

l!.

Do not use CE alignment disk pack unless specifically directed to do so. These packs contain
prerecorded alignment data that can be destroyed if test procedure requires drive to write.
This alignment data cannot be generated in the field.

12.

Do not use customer disk pack for testing purposes.

13.

Keep hands away from actuator during seek operations and when reconnecting leads to
voice coil. Under certain conditions, emergency retract voltage may be present, causing
sudden reverse motion and head unloading.

14.

A 1.5 inch brace is attached to the positioner along with the flex leads and held with one
screw. It can be very easily pushed out of position where it will interfere with servo head
cable. This may result in head crashes.

15.

The solder connections on the flex leads to the linear motor can be easily shorted out by
torqueing down on the screw. The symptom is "popped DC breaker upon attempting heads
load sequence".

16.

The alignment pack track density is 1/2 the track density on a data pack. Cylinder 245 on
the alignment pack is physically 490 on a data pack. A seek to 490 on the data pack can be
visually checked using the alignment pin.

17.

Intermittent, clearable read/write faults tend to be generated on the read/write card (location A3A02). If a fault is indicated, and it clears by hitting CLEAR, watch to see if it appears
some time later. If so, swap this card.

5.1.2.2 FRU Locations - The physical arrangement of the drive is described in Figures 5-1 and Table
5-1. Figure 5-1 separates the drive into three sections. Each section and its assemblies and components
have been assigned a physical location code. All physical location codes shown on Figure 5-1 are listed
in Table 5-1. Table 5-1 identifies the physical location code by title, and refers to the reference page of
the RM02 Disk Drive Technical Manual, Vol. II (EK-2RM02-TM) or RM03 Disk Drive Technical
Manual, Vol II, (EK-2RM03-TM) where the location code is shown.

5-3

Table 5-1

Physical Location Codes

Physical
Location
Code

Name

Al
AlAI
AIA2
AIA3
AIBMI
AICI
AIC2
AIC5
AIC8
AICBI
AICB2
AIFLI
AIKI
AIK2
AIMI
AIS4
AITI
AITBI
AIJIA
AIJIB
AIJIOO
AIPI
A2
A2AOI
A2A02
A2A03
A2A04
A2A05
A2A06
A2A07
A2A08
A2A09
A2AIO
A2BOI
A2B02
A2B06
A2B07
A2B08
A2B09
A2DI
A3
A3AOI
A3A02
A3A03
A3A04
A3A05
A3C6

Base Assembly (AC Power System)
±42 V Supply and Emergency Retract
± 12 and ±20 V Supplies
±5 V Supply
Blower Motor
Servo Capacitor ( +)
Servo Capacitor (-)
Blower Motor Start Capacitor
Transformer Tuning Capacitor
AC Power Circuit Breaker
Power Supply Circuit Breaker
Line Filter
Start Triac
Emergency Retract Relay
Elapsed Time Meter
Deck Interlock Switch
AC Power Transformer
Terminal Board
Power Supply Connector
Power Supply Connector
Power Supply Connector
AC Power Connector
Logic Chassis
Write Clock (806 kHz)
FTU /Head Alignment Card Slot
Fine Servo Decoder
Fault Card
Data Latch
Read PLO
D / A Function Generator
Access Control No.2
Switching Mode Control
Interlocks and Speed Detector
Transmitters and Receivers head Address Register
Receivers
Difference Generator Controls
NRZ to Compensated MFM
Access Control and Index/Sector Decode
Access Control No. I
I/O
Deck Assembly
Control Panel
Head Select and Read Amplifier
Writer
Power Amplifier
Track Servo Preamplifier
Drive Motor Capacitor

Reference
Numbers

5-4

302
31X
32X
33X
302
312
312
302
302
302
302
302
302
312
302
302
302
302
31X-33X
31X-33X
31X-33X
302
OIX
02X
03X
04X
05X
06X
07X
08X
09X
lOX
IIX
12X
16X
17X
18X
19X
23X
25X
26X
27X
28X
29X
302

Table 5-1

Physical Location Codes (Cont)

Physical
Location
Code

Name

Reference
Numbers

A3DMI
A3HBI
A3K5
A3Ll
A3L2
A3L3
A3S2
A3S3
A3VCl

Drive Motor
Hysteresis Brake
Start Triac
Speed Transducer
Velocity Transducer
Pack Cover Solenoid (Optional)
Heads Loaded Switch
Peak Cover Switch
Voice Coil

302
302
302
103
072
102
302
252
312

5.1.2.3 Power Distribution - AC power distribution problems are covered in the troubleshooting
pathfinder. However, a more traditional approach to power distribution problems is detailed in the
followmg paragraphs. The power system can be divided into two sections; ac power and dc power. The
ac power section will cover everything up to the Al CB2 circuit breaker and the dc power section
everything after A lCB2. Refer to Figure 5-2.

AC Power Distribution - Figure 5-2 shows a simplified line drawing of the ac power distribution
system. A complete diagram of the ac power system is found on reference page 302 of the RM02 Disk
Drive Technical Manual, Vol. II or page 302 of the RM03 Disk Drive Technical Description Manual,
Vol. II. Fault isolation should be performed by dropping loads off the A lCBl one at a time.
NOTE
The drive Al CB2 circuit breaker should not be on
when troubleshooting. Drive motor and blower motor
are easily disconnected by P304 and P301 respectively.
Isolating the elapsed time meter and start and run triacs will require a judgement decision as to which
one to disconnect first; anyone may be suspect. Once the fault is isolated, replace the FR U using the
steps outlined in the parts removal and replacement procedures in Chapter 3 of this manual and verify
the repair. Reconnect all dropped loads and retest.

DC Power Distribution - The dc power system starts at Al CB2 which supplies the ac innput power to
transformer Tl. The transformer secondary outputs supply ac power to the dc power supply modules.
The following reference pages of the two Disk Drive Technical Manuals detail the distribution system.
Al CB2, Transformer T 1
and secondary output connections
±42 V Power Supply
± 12 V and ± 20 V Power Supply
± 5 V Power Supply

302
311,312
321,322
331-333

5-5

P3~1
BM1 BLOWER

---~

MOTOR

DRIVE POWER
PLUG P1
AC

START & RUN

[)----;~o-E_R_,_--t__----__I
A1CB1

TRIACS
A 1 K1
A3K5

P30~
DM1 DRIVE

t---~

MOTOR

LOGIC
CONTROL
TIME
POWER
SUPPLY

TRANSFORMER

...........0

----0

J100
T1

A1CB2

A1A03

A1A02

A1A01

±5 VOLT POWER
SUPPLY

± 12 VOLT AND ±20
VOLT POWER SUPPLY

±42 VOLT POWER
SUPPLY AND
EMERGENCY
RETRACT
MA-1902

Figure 5-2 Power Distribution System

If Al CB2 trips when powered on, either excessive power is being drawn through it or Al CB2 is

defective. Excessive power being drawn is more likely the case. This condition indicates a defective
power supply module, transformer, or wiring error or fault. Fault isolation may best be performed by
replacement of power supply modules one at a time. If modules are removed, remember that the
transformer will oscillate with no load on it. Table 5-2 shows the ac input voltages for each power
supply module. Test points are included.

5-6

Table 5-2

Checking AC Inputs to Power Supplies·

Supply to be
checked for
AC Input

Scope Connections
GNDProbe
(AC Input)
(Center Tap)

AC Input
Voltages
(±5%)

±5V

AIA03 -17A
AIA03 -15A

AIA03 -28A

11 Vac

±20V

AIA02-23A
AIA02-21A

AIA02-01A

22Vac

±42V

AIAOI-14A
AIAOI-12A

AIAOI-OIA

44 Vac

+ Probe

*U se card extender for easy access to motherboard pins listed in ttable.

Table 5-3 shows dc voltage test points and readings under load and no-load conditions. Table 5-4
shows typical power supply failure symptoms. Using both these tables should isolate a defective power
supply.

Table 5-3

Check DC Voltages·

Volt-Ohmmeter Connections
Voltage
to be
Checked

+5
-S
+12
-12
+20
-20
+42
-42

Normal Load
P/JIA Mated
P/JIB Mated
+ PROBE

- PROBE

+5 Faston
GND Faston
A1A02 - 27A
AIA02- OIA
+20 Faston
GND Faston
A2A04 - 32B
A2A09 - 17B

GND Faston
- S Faston
A1A02 - OIA
A1A02 - 08A
GND Faston
-20 Faston
A2A09 - l7B
A2A04 - 03B

No Load
P/JIA Separated
P/JIB Separated
+ PROBE

Voltage
Readings

- PROBE

Cannot be checked
Cannot be checked
A1A02 - OIA
A1A02 - 27A
A1A02 - OIA
A1A02 - 08A
AIA02 - 29A
AIA02 - OIA
A1A02
- OSA
AIA02 - OIA
AIAOI - 33A
A1AOl - OIA
AIAOI - OIA
AIAOI - 02A

+5.0 (±O.OS)
-5.0 (±0.05)
+ 12.0 (±0.3)
-12.0 (±0.3)
+20.0 (± 1.0)
- 20.0 (± 1.0)
+42.0 (±2.0)
-42.0 (±2.0)

*Power supply boards Al AO 1 (±42 V) and Al A02 (± 12, ±20 V) must be fitted to two card extenders to permit
access to the pins. Other connections are available when the logic chassis (A2) is raised to the maintenance
position.

5-7

Table 5-4

Typical Power Supply Failure Symptoms

Symptom

Probable Cause

Noticeable ripple at output
(checked with oscilloscope)

Open diode or open filter capacitor.

Less than specified output (ac input ok)

Shorted diode or shorted filter capacitor.

Output decreases significantly
when load is connected

Open bleeder resistor.

If the dc power problem is a frequently blown fuse the indication is towards a module or sub-assembly
that is drawing excessive power rather than a defective power supply module. A systematic replacement of modules is indicated for fault isolation. Table 5-5 shows module and subassembly dc voltage
utilization. This table should limit the number of replacements necessary to isolate a fault.
NOTE
Do not remove or insert modules with power on the
drive.
Using the reference pages to isolate loads by separating plugs may alsso be of some help.
5.1.2.4

Miscellaneous - Card cage backplane voltage pins are as follows:

+5 volts
-5 volts
+20 volts
-20 volts
GND

pin 34B
pin IB
pin 33B
pin 2B
pin 1A and 34A

All slots
Slots AOI-AI0
All slots

Pins are numbered 01 to 17 and 21 to 34. Pin numbers 18, 19 and 20 do not exist.
Test Points "A" and "Z" on all cards are always ground.
Never remove all three power supply boards at the same time. This causes the transformer to go into
oscillation when power is reapplied (NO-LOAD situation).
The ± 5 V power supply cannot be checked without a load on it.
Power supply fuse ratings are as follows:
±5V
±20V
±42V
±12 V

8 A fuse
2 A fuse
6 A fuse
Uses current limiting resistors (51 nat 10 W)

5-8

Table 5-5
Location

Name

Al
AICI
AIC2
AIKI
AIK2

Base
Servo Cap.
Servo Cap.
Run Triac
Emergency Retract
Relay

A2
A2AOI
A2A02
A2A03
A2A04
A2A05
A2A06
A2A07
A2A08
A2A09

Logic Chassis
Write Clock
FTU-HD Align.
Fine Servo Decode
Fault Card
Data Latch
Read PLO
D / A Func. Gen.
Access Cont. #2
Switching Mode
Controls
Interlocks & Speed
Detect
TX RX Head
Address Reg.
RX

A2AIO
A2BOl
A2B02
A2B03
A2B04
A2B05
A2B06
A2B07
A2B08
A2B09
A2BIO
A3
A3AOI
A3A02
A3A03
A3A04
A3A05
A3HBI
A3K5
A3L3
A3VCI

Module and Subassembly DC Voltage Utilization
+5

+12

-12

+20

-20

+42

-42

X
X
X
X

X
X
X
X
X
X
X
X
X

X
X

X
X
X
X
X
X
X
X
X

N/C

NjC
NjC
NjC

NjC
NjC
NjC
NjC

X
X

X
X
X
X
X
X
X
X
X

Difference
Generator Cont.

NRZ to Comp MFM
Access Control
Index/Sector
Access Control #1

X
X

Deck
Control Panel
HD Select Read Amp.
Writer
Power Amp.
Track Servo Pre Amp.
Hysteresis Brake
Start Triac
Pack C over Solenoid
Voice Coil

-5

NjC
X
X
X
X

NjC

X
N/C

NjC

X
X
X

X
X

N/C

X
X

5-9

5.1.3

Initial Fault Analysis

5.1.3.1 Introduction - The scope of this section is to provide a means of determining which major
functional block within the disk subsystem is faulty. The three major functional subsystem blocks are
the RH controller, adapter, and drive. Techniques to diagnose each of these areas will be discussed
separately but should be linked logically to round out a troubleshooting strategy.
Typically, the first step accomplished on any trouble call is to verify the problem as reported or to
ascertain the correct symptoms and begin a logical deductive reasoning process to isolate one of the
three major blocks. Unless there is an obvious reason to go directly to a major block it is usually better
to start cold and begin troubleshooting using the MAINDEC diagnostics. The following subsections
will utilize this process and will cover the major subsystem blocks.
5.1.3.2 Initial Fault Analvsis - RH Controller - The drive will be running on RH 11 or an RH70
controller (in most cases) d·epending on the particular system. To test the RH70 controller, the MAINDEC RH70 Controller Test Diagnostic (MAINDEC-ll-DERHA) can be run. It requires a drive to
run, however. As for the RH11 controller, there is no diagnostic currently available to specifically test
it. However, a special tester called a Massbus Simulator can be used, if available. Additionally, cable
swapping should serve to illustrate if a problem is in the controller or the drive. This, however, requires
a second controller.
5.1.3.3 Initial Fault Analysis - Adapter - Before continuing with troubleshooting the adapter, consider that the cable from RH to adapter may be swapped completely with another cable set to ensure
cable integrity. It also provides a means to identify a defective adapter.
The most powerful tool to fault isolation is the Diskless Diagnostic (MAINDEC-ZZ-CZRMJ). If the
diagnostic fails to isolate the problem, utilize the following technique before module swap-out of the
adapter. The cables interconnecting the drive to the adapter, in most cases, are long enough to attach
the drive to another adapter. (This requires a 2-drive system.) Once this configuration is complete any
battery of tests can be performed to isolate the fault. In multiple RH controller installations, the
defective adapter could be reconfigured to verify the fault, or to indicate the problem may be compatability between RH and adapter.
5.1.3.4 Initial Fault Analysis - Drive - The first step to isolating the drive as a fault source is to verify
the RH and adapter portions (Paragraphs 5.1.3.2 and 5.1.3.3) utilizing the associated analysis procedure. Whenever the diagnostics indicate positioning or major drive fault errors the drive is immediately suspect. A difficult problem to isolate is read/write data problems since the paths cannot be
isolated and verified. Unless the drive can be configured to another adapter by swapping cables and
diagnostics rerun, then pronounce the drive at fault and proceed to the Functional Analysis section for
the drive.
5.1.4

Using The Guides

5.1.4.1 Introduction - This section explains the use of each Fault Isolation Guide (FIG) and how it
can be utilized most efficiently. Paragraphs 5.1.4.3 and 5.1.4.4 detail the resources used by each FIG.
Emphasis is placed on each FIG to isolate only in its respective area. The level of detail goes beyond
the Field Replaceable Unit (FRU) level and points the troubleshooter to print set references ifmore indepth treatment is necessary.
5.1.4.2 FIG Usage Guide - This paragraph will present an overview of the FIG layout and explain the
manner in which the FIG should be utilized. The use of the Fault Isolation Procedures (FIPs) associated with each FIG will also be described.

5-10

The Fault Isolation Guides are designed to isolate a problem to a defective FRU. To cover the complete functionality of the drive, there are four FIGs, one for each of the following areas:
FIG No.1
FIG No.2
FIG No.3
FIG No.4

Power Up and First Seek
R TZ and Random Seeks
Read/Write Data Path
Head Unload and Power Down.

Each FIG starts with a question. If the answer to the question is no, that is the correct FIG to use to
correct the problem. When the answer is yes~ the problem with the drive lies in a functional area
covered by another FIG.
Figure 5-3 is a flow diagram to point to the correct FIG to use. When a FIG has been completely
utilized, and the answer to its appropriate question is "yes", the flow diagram will point to the next
FIG to be used.

GO TO FAULT

>-N_0---4~ ISOLATION GUIDE #1
(PARAGRAPH 5.2)

GO TO FAULT
ISOLATION GUIDE #2
(PARAGRAPH 5.3)

GO TO FAULT
ISOLATION GUIDE #3
(PARAGRAPH 5.4)

GO TO FAULT
ISOLATION GUIDE #4
(PARAGRAPH 5.5)

DRIVE IS FULLY
FUNCTIONAL
MA-1903

Figure 5-3 FIG Determination Flow Diagram

5-11

Each FIG states the starting conditions necessary for that guide's particular procedure. Always ensure
all the starting conditions are met before proceeding into the FIG.
The FIG itself consists of three columns. The first column, Step, is self-explanatory. The items in the
second column, labeled Procedure/Questions are either instructions to the service personnel or questions to be answered by the service personnel. If the answer to a question is "yes", the next place to go
is to the very next step. If, however, the answer to the question is "no", the place to go is to the FIP
indicated in the third column of the FIG, entitled Action. The FIPs for a given FIG follow immediately after the particular FIG.
Each FIP begins with a statement that describes the problem encountered. There are then a series of
possible solutions to the problem, arranged so that the most likely solution is first, the second most
likely solution next, and so on. The solutions usually make reference to specific FRUs which should be
replaced. After some of the possible solutions are page numbers, representing references to the print
sets contained within the RM02 Disk Drive Technicai Description M anuai, Voiume ii, or the RM03
Disk Drive Technical Description Manual, Volume II.
Occasionally, a step in a FIP will be a "jump" to another step in that FIP or to another Fault Isolation
Guide. These statements are self-explanatory. Also there are some references to test points or other
procedures located in Paragraphs 5.1.4.3 and 5.1.4.4, respectively. These steps should be done sequentially, or as specifically described.
If none of the possible solutions given in a FIP will solve the problem stated at the beginning of that

FIP, the recommended procedure is to call for regional support.
5.1.4.3 FIG Test Point Locator - The following table is a list of test points referenced in the Fault
Isolation Guide. The test points are listed by signal name, location, and reference pages found in the
disk drive technical manuals.

Table 5-6 Test Point Locator
Signal

Test Point

Page

+ Remote Start
Speed Analog
- Speed Pulses
+ Up to Speed Enable
+ Up to Speed
+ Up to Speed Delayed
Enable
- Servo Dibits
+ Servo Dibits
+ Track Servo
+ Cyl. Detect A
+ Cyl. Detect B
Summing Amp Output
Velocity
Fine Positioning Analog

"C" A2AI0
"E" A2A 10
"D" A2AI0
"D" A2AI0
"B" A2A04
"F" A2AI0

102
103
104
104
43
104

A2A03 extended pin 25B
A2A03 extended pin 23B
"H" A2A03
"F" A2A03
"G" A2A03
"E" A2A07
"F" A2A07
"F" A2A08

32
32
35
35
35
72
72
84

5-12

5.1.4.4 FIG Test Point Procedures - The following test point procedures are referenced by the Fault
Isolation Guide. Each procedure details the manual intervention, if any, as well as scope settings and
desired waveform results. Several procedures are added at the end to make in-depth troubleshooting of
the servo system easier. Those extra procedures are not referred to by the FIG since test point references are kept to a minimum.
1.

Manual Head Loading
a. The power amplifier must be disconnected before manual head loading.
b.

Never load heads onto a stopped disk pack.

Never load or unload heads slower than 7 inches/second.

Heads should be unloaded immediately if unusual noise occurs when heads are manually loaded.

+ Remote Start
Test Point:

C A2AIO

Reference Page:

102

Scope:

2 V/Div - Drive Not Loaded
5 ms/Div - Spindle At Rest

Drive:

Not loaded, spindle at rest.

Observe:

+4 V if Local/Remote switch is in Local or if in Remote the drive
is sensing a remote start command.

Speed Analog
Test Point:

B A2AIO

Reference Page:

103

Scope:

2 V/Div
5 ~s/Div

Drive:

From dead stop with pack loaded hit start and observe the pulses.

Observe:

5 V p-p waveforms indicating spindle rotation.

- Speed Pulses
Test Point:

D A2AIO

Reference Page:

104

Scope:

2 V /Div
20 ~s/Div

Drive:

Pack is spinning up or is at speed.

Observe:

5 V p-p waveforms approximately 40 ~s in duration.

5-13

+ Up To Speed Enable
Test Point:

E A2AIO

Reference Page:

104

Scope:

2 V jDiv
5 msjDiv

Drive:

Pack is loaded; hit start. Approximately 6-9 seconds later observe
signal change

Observe:

Initially 0 V; after 6-9 seconds, +4 V.

Up To Speed
Test Point:

B A2A04

Reference Page:

Scope:

2 V jDiv
I msjDiv

Drive:

Pack is loaded; hit start; signal changes after approximately 6-9
seconds

Observe:

Initially 0 V, 6-9 seconds after hitting start, +4 V indicates pack is
Up To Speed.

+ Up To Speed Delayed Enable
Test Point:

F A2AIO

Reference Page:

104

Scope:

2 V jDiv
I msjDiv

Drive:

Pack loaded; hit start; signal changes approximately 10 seconds
after Up To Speed true.

Observe:

o V initially; 10 seconds after Up To Speed is true; signal changes
to +4 V.

+ Servo Dibits
Test Point:

23B A2A03

Reference Page:

5-14

- Servo Dibits
Test Point:

25B A2A03

Reference Page:

Scope:

Mount the A2A03 card on an extender. This allows easy access to
pins 23B and 25B
0.2 V IDiv
0.5 ~~/Div

Drive:

With pack spinning and heads loaded. The heads may be manually
loaded with similar results.

Observe:

Figure 5-4 on both pins.

av. --~-------------+-------------+---------~~
.2 V/OIV .
. 5 j.lSEC.lOI V
SERVO OIBITS
MA-1444

Figure 5-4 Servo Dibits

10.

+ Track Servo
Test Point:

H A2A03

Reference Page:

Scope:

2 V/Div
5 ms/Div

Drive:

With voice coil power amplifier disconnected, load heads and
manually move carriage back and forth over disk surface.

Observe:

5 V p-p waveforms with varying cycle time due to different track
crossing speeds as in Figure 5-5.

5-15

o ~----~~----+---~--r-~-+----~

2 V/DIV.
5 mSEC./DIV.
+TRACK SERVO
MA-1445

Figure 5-5 +Track Servo Signal

11.

12.

+ Cycle Detect A
Test Point:

F A2A03

Reference Page:

+ Cycle Detect B
Test Point:

G A2A03

Reference Page:

Scope:

2 V/Div
5 ms/Div

Drive:

With voice coil power amplifier disconnected, load heads, and
manually move carriage back and forth over disk surface.

Observe:

o to +4 V pulses varying in time due to differences in carriage
speed as shown in Figure 5-6.

2 V/DIV.
5 mSEC/DIV.

lJlJUJ

oV.====L---~-L~------------~~~~

+ CYL. DETECT A
+ CYL. DETECT B
MA-1446

Figure 5-6 CYL Detect Signals
5-16

13. Summing Amp. Output
Test Point:

E A2A07

Reference Page:

Scope:

5 V /Div
1 ms/Div

Drive:

With voice coil power amplifier disconnected, hit start, wait for up
to speed, manually load heads and move carriage back and forth
over disk surface.

Observe:

Initially (before start) 0 V, after 20-30 seconds - 10 V. When heads
are moved observe 20 V p-p varying waveforms.
NOTE
Fault will illuminate if servo heads fail to sense dibits. Only way to clear is to unload heads, stop disk,
hit Fault button. Also, ready light will come on when
over dibit pattern.

14. Velocitj

Test Point:

F A2A07

Reference Page:

Scope:

1 V /Div
0.1 °ms/Div

Drive:

With voice coil power amplifier disconnected, hit start, wait for up
to speed, manually load heads and move carriage back and forth
over disk surface.

Observe:

On forward travel: 1 V p-p waveform; swings negative then falls to
zero.
On reverse travel: 1 V p-p waveform; swings positive then falls to
zero.

15. Fine Positioning Analog
Test Point:

F A2A08

Reference Page:

Scope:

2 V/Div
1 ms/Div

Drive:

With voice coil power amplifier disconnected, hit start, wait for up
to speed, manually load heads and move carriage back and forth
over disk surface.

Observe:

Approximately 10 V p-p waveforms as carriage is moved back and
forth.
5-17

5.2. FAULT ISOLATION GUIDE NO.1
Will the drive come ready from power on? If yes, refer to Figure 5-3 in Paragraph 5.1.4.2 to determine
which guide should be used next. If the drive will not come ready from power on, continue with this
guide.
The following starting conditions are assumed by this guide:
Start switch is not pressed
Write Protect switch is not pressed
Local/Remote switch to Remote position
No pack in drive
Pack cover is closed
Cables A and B are connected to the adapters
Drive is in normal operating position with top case cover removed
Power Sequence cable is installed
CBl is off
CB2 is off
AC power at the outlet is correct for the drive (i.e., 110/50 Hz, 220/60 Hz, etc.)
If all of the above conditions are met, refer to step 1-1 in FIG 1 and proceed from there.

5-18

FIG 1
Step

Procedure / Questions

1-1

Plug drive power cord into ac outlet

1-2

Turn drive on. Does CBl stay on?

FIP I-I

1-3

Does blower motor start?

FIP 1-2

1-4

Ensure Start switch is not pressed and that CB2 is off.
Does drive motor stay off?

FIP 1-3

1-5

Turn CB2 on. Does it stay on?

FIP 1-4

1-6

Ensure Start switch is not pressed. Turn CB 1 and
CB2 on. Does drive motor stay off?

FIP 1-5

1-7

Is Start light off?

FIP 1-6

1-8

Is Ready light off?

FIP 1-7

1-9

Ensure Write Protect switch is not pressed. Is the
Write Protect light off?

FIP 1-8

1-10

Examine the front panel and fault card A2A04. Are
all the fault lights out?

FIP 1-9

1-11

Press Write Protect switch. Does the Write Protect
indicator come on?

FIP 1-10

1-12

Attempt to raise the pack access cover. Does it open?

FIP I-II

1-13

Is air flowing in shroud area?

FIP 1-12

1-14

Mount a scratch pack and close cover.

1-15

Set Local/Remote switch on A2AIO card to Local.

1-16

Ensure Start switch is not pressed. Does the drive motor stay off?

FIP 1-5

1-17

Press the Start switch. Does the Start light come on?

FIP 1-13

1-18

Ensure the Start switch is pressed. Does the drive motor come on?

FIP 1-14

1-19

Does the drive motor continue to run, even after several seconds?

FIP 1-15

Action
(if answer is NO)

5-19

1-20

Do both the thermo protect circuit breaker and the
main breaker CB 1 stay on after the drive motor has
started to run?

FIP 1-16

1-21

Ensure the drive motor is running and the Start indicator is lit. Is the Ready light flashing?

FIP 1-17

1-22

Ensure the Start light is on and that the Ready light is
flashing. After the Ready has been flashing for approximately one minute, have the heads loaded?

FIP 1-18

1-23

Do the heads stay loaded?

FIP 1-19

1=24

Ensure the heads have loaded. Do they not seek to the
full mechanical stop?

FIP 1-20

1-25

Ensure the heads have loaded. Do they not creep forward to the full mechanical stop?

FIP 1-21

1-26

Ensure the heads are loaded. Does the Ready light
come on?

FIP 1-22

1-27

The drive is now powered up; the heads have successfully loaded at the home position and the drive is
ready to accept commands.

FIP 1-1
CB1 does not stay on when drive is turned on.
Step

Print Set Page
Possible defective motor. Disconnect P301. Turn on
CB1. If CB1 stays on, replace blower motor. (Refer to
Paragraph 3.10.)

302

Possible defective elapsed time meter

302

Possible short or poor connection in wiring harness

302

Possible defective CB 1

FIP 1-2
Blower motor does not start.
Step

Print Set Page
Possible disconnected blower motor plug P301

302

Possible jammed impeller

302

Possible defective blower motor

302

5-20

Possible defective start winding or starting capacitor
AIC5

302

Possible defective or poor wiring connections

302

Possible loose wiring connections on A I CB I circuit
breaker or line filter A I FL I

302

Possible defective circuit breaker A I CBI or line filter
AIFLI

302

Excessively low ac input voltage

302

FIP 1-3
With Start switch not pressed and CB2 off, the drive motor starts.
Print Set Page

Step
Possible defective run triac AIKI. (Refer to Paragraph 3.14 for removal and replacement procedure.)

302

Possible defective A2A 10 cord (ASGU)

102-103

Possible defective start switch and wiring harness

252

FIP 1-4
CB2 does not stay on when it is turned on.
Print Set Page

Step

Voltage selection block (TBI) is miswired

302

Possible short on transformer TI or tuning capacitor
AIC8

302

WARNING
Turning capacitor is changed to 440 volts
3

Possible defective power supply module(s) - AIAOI
(5SJV), A1A02 (5SKV), A1A03 (ASHV) (refer to
Paragraph 3.9 for removal and replacement procedure)

312, 322, 333

CAUTION
Do not power up drive with all three power supply
modules removed. Do not remove any of the modules
with the drive powered up.
4

Possible defective circuit breaker CB2

5-21

302

FIP 1-5
With the Start switch not pressed, and CBI and CB2 on, the drive motor starts.
Step

Print Set Page
Possible defective run triac AIKI. Refer to Paragraph 3.14 for removal and replacement procedure.

302

Possible defective A2A 10 cord (ASGV)

102-103

Possible defective Start switch or wiring harness

252

Possibly receiving a remote start condition via
Sequence Pick and Hold. Check test point C (TPC)
on -the A2AIO (ASGV) cord. Signal name is Remote
Start. +4 V indicates Start, 0 V indicates No Start

102-103

Possible defective Cable A or adapter problem

232

FIP 1-6
Start light is on, even though Start switch is not pressed.
Step

Print Set Page
Possible defective Start switch. Refer to Paragraph
3.16 for removal and replacement procedure.

252

Possible short on control panel or wiring harness

252

FIP 1-7
Ready light is on, even though drive has not been started.
Step

Print Set Page
Possible defective A2A04 card (EKFV)

102

Possible defective A2A 10 card (ASGV)

Possible short in wiring harness on control panel

252

FIP 1-8
Write Protect light is on, even though Write Protect switch is not pressed.
Step

Print Set Page
Possible defective receivers card - A3BOI

113

Possible short in wiring harness or defective WRITE
Protect switch or defective control panel

252

5-22

FIP 1-9
At least one of the fault lights on either the front panel or the fault card A2A04 is on.
Step

Print Set Page
Attempt to clear fault(s) by flipping S 1 on the A2A04
card or hitting the Fault switch on the front panel.

252, 41-45

Determine which fault lights are on (refer to Figure 57). If the voltage fault LED is on, go to step 8 of this
FIP. Otherwise, continue with step 3.

41-45

MAINTENANCE SWITCH ES AN D
FAULT INDICATORS ON CARD EDGE

CLEAR
MAINT FAULT CLEAR
NORM
VOLTAGE FAULT
WRITE FAULT

CR2

HEAD SELECT FAULT

CR3

WRITE OR READ FAULT

CR4

NOT ON CYLINDER AND
(WRITE OR READ) FAULT

CRS

MAINT UNIT DISABLE

NORM

MA-1904

Figure 5-7 Fault Indicators on Edge of A2A04 Card

5-23

Check for ± 5 V on card cage and check the ± 5 V
fuses. Refer to Paragraph 5.1.2.3 for dc power distribution problems.

331-333

Check for ± 12 V and ±20 V on card cage and check
the appropriate fuses. Refer to Paragraph 5.1.2.3 for
dc power distribution problems.

321-322

Check the ±42 V plug (PA09) on the bottom of the
card cage and check the ± 42 V fuses.

311-312

Possible defective fault card A2A04 (EKFV)

41-44

If Volta2e Fault LED is still on. call for re2ional suoport. If~any other fault indicators are still on, co~
tinue. Otherwise, return to step 1-11 of Fault
Isolation Guide No.1.

Possible defective fault card A2A04 (EKFV)

Reexamine the fault indicators and proceed as directed.
CR2 - Write Fault - if ON, go to step 10
CR3 - Head Select Fault - if ON, go to step 16
CR4 - Read or Write Fault - if ON, go to step 22
CR5 - Not On Cylinder and (Write or Read) - if ON,
go to step 28
Front Panel - Servo Track Fault - if ON, go to step
35

Possible defective Writer card - A2A03

271-274

Possible defective NRZ to MFM card - A2B07

171-173

Possible defective Write Clock and Write Data card A2BOI

111-113

Possible defective Receivers card - A2B02

121-124

Possible defective Interlocks and Speed Detector card
- A2AI0

101-104

If the Write Fault LED is still on, call for regional
support. If any fault indicators are still on, return to
step 9. Otherwise, return to step I-II of Fault Isolation Guide No.1.

Possible defective Head Select and Read Pre-amp
card - A3A02

261-263

Possible defective Transmit and Receive Head Address Register card - A2BOI

111-113

5-24

41-44

Possible defective Receiver card - A2B02

Possible defective "A" cable

Possible adapter problem

If the Head Select LED is still on, call for regional
support. If any fault indicators are still on, return to
step 9. Otherwise, return to step 1-11 of Fault Isolation Guide No.1.

Possible Receiver card - A2B02

121-124

Possible defective Interlocks and Speed Receiver card
- A2AI0

101-104

Possible defective 'A" cable

Possible defective Writer card - A3A03

Possible adapter problem

If the Read or Write Fault LED is still on, call for
regional support. If any fault indicators are still on,
return to step 9, Otherwise, go to step I-II of Fault
Isolation Guide No.1.

Possible defective A ccess Control card - A2B09

191-193

Possible defective Receiver card - A2B02

121-124

Possible defective Write card - A3A03

271-274

Possible defective Interlocks and Speed Detector card
- A2AI0

101-104

Possible defective "A" cable

Possible adapter problem

If the Not on Cylinder and (Write or Read) Fault
LED is still on, call for regional support. If any fault
indicators are still on, return to step 9. Otherwise, go
to step 1-11 of Fault Isolation Guide No.1.

Possible defective Access Control No.1 card - A2B09

191-194

Possible defective A/O Function Generator card A2A07

71-73

Possible defective Access Control and Index/Sector
card - A2B08

181-184

5-25

121-124

271-274

Possible defective Track Servo Pre-amp - A3A05

If Servo Track Fault is still on, call for regional support. If any other fault indicators are still on, continue. Otherwise, return to step 1-11 of Fault
Isolation Guide No.1.

291

FIP 1-10
Write Protect indicator does not come on when Write Protect is pressed.

Step

Print Set Page
Loose cable connection going to control panel

252

Possible defective switch (S4) on control panel.

252

Possible defective LED (1 CR6) on control panel.

252

FIP 1-11
The pack access cover will not open.

Step

Print Set Page
Ensure Start switch is not pressed

102

Possible defective Interlocks and Speed Detector card
- A2AI0

102

Possible defective pack cover solenoid, or solenoid
out of adjustment. Refer to Paragraph 3.26 for adjustment procedure

102

Possible defective cab.1ing from card cage to pack
cover solenoid

102

FIP 1-12
Air is not flowing in shroud area.

Step

Print Set Page
Absolute filter clogged. Refer to Paragraphs 3.11 and
3.12 for removal and replacement procedure.

Squirrel cage fan on blower motor loose. Refer to
Paragraph 3.10 for removal and replacement procedure.

Possible physical obstruction or leaky or damaged air
flowpath
5-26

FIP 1-13
With the Start switch pressed, the Start light does not come on.

Step

Print Set Page
Possible defective Start switch on control panel.

252

Possible defective Start light (I CR2) on control panel.

252

Possible loose or defective wiring or connections on
control panel.

252

FIP 1-14
With the Start switch pressed, the drive motor does not come on.

Step

Print Set Page
Possible defective pack covers interlock - A353

252

Possible defective deck interlock - AIS4

302

Possible defective start triac - A3K5. Refer to Paragraph 3.13 for removal and replacement procedures.

302

Possible defective run triac - Al K 1. Refer to Paragraph 3.14 for removal and replacement procedures.

302

Possible defective Interlocks and Speed Detector card
- A2AIO

101-104

Possible defective drive motor or wiring connection
(P304).

302

Thermo protect tripped or defective

302

FIP 1-15
Drive motor stops after running for several seconds.

Step

Print Set Page
Possible defective Interlocks and Speed Detector card
- A2AIO

101-104

Possible defective Start switch on control panel

252

Possible defective run triac - Al Kl. Refer to Paragraph 3.14 for removal and replacement procedures.

302

Possible defective drive motor brake (AIHBI) or
heads unloaded switch (A3S2). Refer to Paragraphs
3.20 or 3.30, respectively, for removal and replacement procedures.

302

5-27

Possible defective speed transducer (A2Ll) or lack of
speed pulses. Table 5-7 lists the test points that can be
used to trace the path of the speed pulses.

Table 5-7

Speed Pulse Path Test Points

Test Point

Card

Signal

Print Set Page

B
D
E
F

A2AI0
A2AI0
A2AI0
A2AI0

Speed Analog
- Speed Pulses
+ Up To Speed Enabled
+ Delayed Up To Speed Enabled

102-104
102-104
102-104
102-104

Possible defective run winding of drive motor or
thermo protection circuit breaker. Refer to Paragraph 3.20 for removal and replacement procedure.

302

Possible voltage problem or blown fuses or defective
circuit breaker AICBl

302

FIP 1-16
Either the thermo protect circuit breaker or the main circuit breaker CBl or both trip after the drive
motor has started.
Step

Print Set Page
If the thermo circuit breaker trips:

Possible defective start triac - A3K5. Refer to
Paragraph 3.13 for removal and replacement
procedure.

302

Possible defective drive motor starting capacitor
A3C6 or defective drive motor start winding.
Refer to Paragraph 3.20 for removal and replacement procedure.

302

If the main circuit breaker CB 1 trips:

Possible defective drive motor. Refer to Paragraph 3.20 for removal and replacement procedure.

302

Possible defective circuit breaker CBl.

302

Possible loose wiring connections in ac power
wiring.

302

5-28

FIP 1-17
With the drive motor running, and the Start indicator lit, the Ready light does not flash.

Step

Print Set Page
Possible defective Interlocks and Speed Detect card A2AI0

102

Possible defective Fault card - A2A04

Possible defective wiring between A2AI0 and control
panel.

252

Possible defective LED 1CR3 on control panel

252

FIP 1-18
After the Ready light has been flashing for approximately one minute, the heads have not loaded.

Step

Print Set Page
a,

Verify the + Up To Speed signal by checking
test point B on the A 2A04 card. Refer to part F
of Paragraph 5.1.4.4 to do this. The signal
should be +4 V. If it is, skip to step 2. If it is not
+4 V, proceed with b.

103-104

Possible defective Interlocks and Speed Detector
card - A2AI0

101-104

Possible defective wiring speed transducer (J201,
PA80)

103-104

Possible defective speed transducer - A3Ll. Refer to Paragraph 3.24 for removal and replacement procedure.

103-104

If the heads still will not load, call for regional
support. If they do load, return to step 1-23 of
Fault Isolation Guide No.1.

The drive may be in constant "emergency retract"
mode.
a.

Possible defective relay A lK2 on the ±42 V supply card (AIA01).

312

Possibly incorrectly picking relay (A 1K2) due to
defective Interlocks and Speed Detect card
(A2AI0) or defective Fault card (A2A04) or
maladjusted head load switch (A35S). Refer to
Paragraph 3.30 for adjustment procedure.

443

Possible voltage fault. Check all voltages for
fault conditions.

043

5-29

The positioner may not be able to be driven.
a.

Possible defective Servo Fault Card - A2B09

Possible defective Summing Amp card - A2A07

194
072

Possible defective Power Amp card - A2A09

092

Possible mechanical obstruction of positioner or
power amplifier cable (1200) not connected.

282

FIP 1-19
The heads retract after ioading.

Print Set Page

Step
a.

Use the special test procedures in part Hand J of
Paragraph 5.1.4.4 to check for servo dibits on
A2A03 pins 23B and 25B.

Possible defective Track Servo Preamp A3A05

292

Possible defective servo head.

292

Possible defective or damaged wiring harness
(Jl, J8, etc.)

292

Possible defective Servo Tracking Logic card A2A03

Possible defective logic in servo loop. The following
cards make up most of the logic:

31-35

A2A07, Reference pages 71-73
A2A08, Reference pages 81-85
A2A09, Reference pages 91-93
A2B06, Reference pages 161-165
A2B08, Reference pages 181-184
A2B09, Reference pages 191-194

FIP 1-20
The heads load and then seek to the full mechanical stop.

Print Set Page

Step
Heads stay at full mechanical stop.
a.

Possible defective power amplifier - A3A04

5-30

281-282

Possible defective D / A function generator A2A07

71-73

Possible defective Access Control No.2 card A2A08

81-85

Possible defective Access Control No. 1 card A2B09

191-194

Check velocity transducer connection,

Heads retract from full mechanical stop.
a.

Possible defective Power Amplifier - A3A04.

281-282

Possible defective D / A Function Generator A2A07.

71-73

Possible defective Fine Servo Decoder card A2A03

31-35

Possible defective Switching !vIode Control card
- A2A09.

91-93

Check velocity transducer connections.

FIP 1-21
The heads load and then creep forward to the full mechanical stop,
Print Set Page

Step
Possible defective Access Control No. 2 card A2A08

81-83

Possible defective Access Control No.1 card - A2B09

192

Possible defective Fine Servo Decoder card - A2A03

31-35

Possible defective D / A Function Generator card A2A07

71-73

Possible defective Switching Mode Control card A2A09

NOTE
If ±12 V differs by more than 1.6 V, the dibits will
not be evenly amplified and a permanent offset
condition will occur.

5-31

FIP 1-22

With the heads loaded, the Ready light does not come on
Print Set Page

Step

Possible defective Interlocks and Speed Detect card A2AIO

101-104

Possible defective Fault card - A2A04

41-45

Possible defective Servo Fault card - A2B09

191-194

Possible defective wiring harness to control panel

341-343

5-32

5.3 FAULT ISOLATION GUIDE NO.2
Will the drive do Return To Track Zero (R TZ) and random seeks? If yes, refer to Figure 5-3 in
Paragraph 5.1.4.2 to determine which guide should be used next. If the drive will not do RTZ and
random seeks, continue with this guide.
To correctly utilize this Fault Isolation Guide a Field Test Unit (FTU) is required. Paragraph 2.7.2
details the FTU installation procedure and explains the controls and indicators. A working knowledge
of this information is a prerequisite for attempting to use FIG No.2. This guide assumes the drive in
question can come up to a drive ready state.

5-33

FIG 2
Step

Action

Procedure / Questions

(if answer is NO)
2-1

Install the FTU as described in Paragraph 2.7.2. Set
the FTU switches as indicated in Paragraph 2.7.3.2.
Ensure the WRT-RO SELECT is off.

2-2

Turn on the FTU and then the drive power. Mount a
scratch pack and then make the drive ready.

2-3

Actuate R TZ on the FTU. Did the drive do an RTZ?

FIP 2-1

2-4

Set the FTU for Continuous Seeks and set all cylinder
switches down. One by one, select/deselect each cylinder address switch (1-512). Does each switch have
an appropriate effect on the motion of the carriage?

FIP 2-2

2-5

Set FTU to make the drive seek to track 822 decimal
(1466 octal). This is the Last Track. Does the drive
seek to Last Track?

FIP 2-3

2-6

Set the FTU to make the drive seek to track 823 decimal (1467 octal). Does an error indication appear?

FIP 2-4

2-7

Reset the drive error generated in step 2-6. Set the
FTU to perform continuous, random seeks. Does the
drive do random seeks for five minutes without errors?

FIP 2-5

2-8

The drive is now reasonably capable of performing
random seeks without errors.

FIP 2-1
The drive did not do an RTZ when RTZ on the FTU was actuated
Step

Print Set Page
Possible defective Access Control and Index/Sector
Decode card - A2B08

183

Possible defective Access Control No.1 card - A2B09

194

Possible defective Access Control No. 2 card A2A08

Possible defective D / A Function Generator card A2A07

72-73

5-34

Possible defective Receivers card - A2B02

123

Possible defective Switching Mode Control card A2A09

232

Possible defective FTU or cable A

FIP 2-2
Changing the cyiinder address switches does not correctly affect the carriage motion.
Ensure the FTU is set for CONT (continuous seeks)

Possible defective Access Control and Index/Sector
Decode Card - A2B08

183

Possible defective Difference Generator and Control
card - A2B06

162-165

Possible defective D / A Function Generator card A2A07

72-73

Possible defective Receivers card - A2B02

122-123

Possible defective Switching Mode Control card A2A09

92-93

Possible defective Access Control No.1 card - A2B09

191-194

Possible defective FTU or cable A

FIP 2-3
Drive does not seek to Last Track.
Print Set Page

Step
Possible defective Access Control and Index/Sector
Decode card - A2B08

183

Possible defective Difference Generator Control card
- A2B06

162-164

Possible defective D / A Function Generator card A2A07

Possible defective Receivers card - A2B02

122-123

Possible defective Switching Mode Control card A2A09

92-93

Possible defective FTU or cable A

5-35

FIP 2-4
No error is indicated when the drive attempts to seek to track 823 decimal (an illegal address).
Print Set Page

Step
Possible defective Access Control and Index/Sector
Decode card - A2B08

184

Possible defective Difference Generator Control card
- A2B06

162-164

Possible defective D / A Function Generator card A2A07

Possible defective Receivers card - A2B02

122-123

Possible defective Switching Mode Control card A2A09

92-93

Possible defective FTU or cable A

FIP 2-5
Drive will not do continuous random seeks for five minutes, error free.
Step

Print Set Page
Check the velocity gain adjustment. Refer to Paragraph 4.1 for the adjustment procedure.
184

Possible defective Access Control and Index/Sector
Decode card - A2B08

Possible defective Difference Generator Control card
- A2B06

Possible defective D / A Function Generator card A2A07

Possible defective Receivers card - A2B02

122-123

Possible defective Switching Mode Control card A2A09

92-93

Possible defective FTU or cable A

5-36

5.4 FAULT ISOLATION GUIDE NO.3
Will the drive read and write correctly? If yes, refer to Figure 5-3 in Paragraph 5.1.4.2 to determine
which guide should be next. If the drive will not read and write correctly, continue with this guide.
To correctly utilize this Fault Isolation Guide a Field Test Unit (FTU) is required. Paragraph 2.7.2
details the FTU installation procedure and explains the controls and indicators. A working knowledge
of this information is a prerequisite for attempting to use FIG No.3. This guide assumes the drive in
question can come ready and can perform all the seek operations described in Fault Isolation Guide
No.2.
The starting conditions for FIG No.3 are:
1.

The Local/Remote switch is in the Local position.

A scratch pack is mounted in the drive.

The FTU is installed as per Paragraph 2.7.2.

The FTU switches are set for continuous write/formats using sequential heads and sequence
forward as outlined in Paragraph 2.7.3.3.
NOTE
When using the FfU to isolate Read/Write problems, Table 5-8 may be valuable. The routines are
listed from lesser to greater complexity.
Table 5-8

FTU Read/Write Sequence

Cylinder

Mode

Heads

1
2
3
4
5
6

Write/Format
Write/Read
Write-Format
Write/Read
Write-Format
Write/Read

Manual Heads
Manual Heads
Seq uen tial Heads
Sequential Heads
Sequential Heads
Sequential Heads

Direct
Direct
Direct
Direct
Sequential Mode
Sequential Mode

5-37

FIG 3
Step

Procedure / Questions

Action
(if the answer is NO)

3-1

Set the FTU and the drive to perform a continuous
Write/Format using sequential heads and sequence
forward. Does this happen without any drive faults?

FIP 3-1

3-2

Set the FTU and the drive to perform a continuous
Write/Format using sequential heads and sequence
forward (as in step 3-1). Does this happen without
any FTU faults?

FIP 3-2

3-3

Set the FTU to perform a continuous, WriteiFormat
using sequential heads and sequence forward (as in
step 3-1). Does this happen without an indication of
FA UL T on only some addresses?

FIP 3-3

3-4

If no faults have occurred while using the FTU, but
faults did occur while running some diagnostics,
check for M7684 ECO No.7 - "Consecutive Reads
While In Offset Mode."

3-5

Set the FTU to perform continuous reads using sequential heads and sequence forward as detailed in
Paragraph 2.7.2.2. Does this happen without any address errors?

FIP 3-4

3-6

Set the FTU to perform continuous reads using sequential heads and sequence forward (as in step 3-5).
Does this happen without any data errors?

FIP 3-5

3-7

Set the FTU to perform random WRT.RD functions
with sequential heads, as described in Paragraph
2.7.2.2. Run for five minutes. Does this happen without any errors?

FIP 3-6

3-8

The drive is now reasonably sure of being able to
read, write and seek without errors.

FIP 3-1
There is a fault on the drive when performing a continuous write/format using sequential heads and
sequence forward.
Step

Print Set Page
Attempt to clear the fault by flipping SI on the fault
card - A2A04 or by hitting the Fault switch indicator
on the front panel of the drive.

5-38

252,41-45

Determine which fault lights are on (refer to Figure 57). If the voltage fault LED (CRl) is not on, go to
step 7. Otherwise, contin ue with step 3 of this FIP.

Check the ±5 V on the card cage and check the ± V
fuses. Refer to Paragraph 5.1.2.3 for dc power distribution problems.

331-333

Check ± 12 V and ±20 V on the card cage, and check
the fuses. Refer to Paragraph 5.1.2.3 for dc power distribution problems.

321-322

Check the ±42 V plug PA09 on the bottom of the
card cage. Check the ±42 V fuses.

311-312

Possible defective Fault card - A2A04. If the voltage
fault LED is still on after this card is replaced, call for
regional support. If no faults are indicated, return to
step 3-1 of Fault Isolation Guide No.3. Otherwise,
continue with this FIP.

41-44

Reverify which faults are indicated and proceed as
specified.
CR2 - Write Fault - if ON, go to step 8
CR3 - Head Select Fault - if ON go to step 14
CR4 - Read or Write Fault - if ON, go to step 20
CR5 - Not On Cylinder and (Write or Read) - ON,
go to step 26
Front Panel - Servo Track Fault - if ON, go to step
33
I

Possible defective Write card - A3A03

271-274

Possible defective NRZ to MFM card - A2B07

171-173

Possible defective Transmitters and Receivers/Head
Address Register card - A2BOI

111-113

Possible defective Receivers card - A2B02

121-124

Possible defective Interlocks and Speed Detector card
- A2AI0

101-104

If the Write Fault LED is still on, call for regional
support. If any fault indicators are still on, return to

step 7. Otherwise, return to step 3-2 of Fault Isolation
Guide No.3.
14

Possible defective Head Select and Read Preamp card
- A3A02

5-39

261-263

Possible defective Transmitters and Receiver jHead
Addresss Register card - A2BO 1

111-113

Possible defective Receivers card - A2B02

121-124

Possible defective cable A

Possible adapter problem

If the Head Select Fault LED is still on, call for re-

gional support. If any other fault indicators are still
on, return to step 7. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.
20

Possible defective Receivers card - A2B02

121-124

Possible defective Interlocks and Speed Detector card
- A2A10

101-104

Possible defective cable A

Possible defective Writer - A3A03

Possible adapter problem

If the Read or Write Fault LED is still on, call for
regional support. If any other fault indicators are still

271-274

on, return to step 7. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.
26

Possible defective Access Control No.1 card - A2B09

191-193

Possible defective Receivers card - A2B02

121-124

Possible defective Writer card - A3A03

271-274

Possible defective Interlocks and Speed Detector card
- A2A10

101-104

Possible defective cable A

Possible adapter problem

If the Not On Cylinder and (Write or Read) LED is
still on, call for regional support. If any other fault
indicators are still on, return to step 7. Otherwise, return to step 3-2 of Fault Isolation Guide No.3

Possible defective Access Control No.1 card - A2B09

191-194

Possible defective AjD Function Generator card A2A07

71-73

5-40

Possible defective Access Control and Index/Sector
Decode card - A2B08

181-184

Possible defective Track Servo Preamp - A3A05

291-295

If the Servo Track Fault indicator is still on, call for
regional support. If any other fault indicators are still
on, return to step 7. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.

FIP 3-2
There is a fault on the FTU when performing a continuous write format using sequential heads and
sequence forward.
Print Set Page

Step
Determine what type of fault has occurred and proceed as indicated.
If the FTLJ shows a Clock Error (no servo clock from
drive), go to step 2
If the FTU shows an S-C Error (counters do not
agree), go to step 6
If the FTU shows an S-M Error (error count does not
agree), go to step 12
If the FTU shows an Address Error, go to step 17
If the FTU shows a Data Error, go to step 27
If the FTU shows a Seek Error or a Fault (both
turned on by the drive), go to step 37.

Possible defective Write Clock card - A2AO 1.

11-12

Possible defective Transmitter and Receivers/Head
Address Register card - A2BO 1.

111-113

Possible defective FTU or cable on FTU

If the FTU still shows Clock Error, call for regional
support. Otherwise repeat step 3-2 of Fault Isolation
Guide No.3 and continue from there.

Possible defective Fault card - A2A04

41-45

Possible defective Access Control and Index/Sector
Decode card - A2B08

181-184

Possible defective Transmitters and Receivers/Head
Address Register - A2BO 1

111-113

Possible defective Receivers card - A2B02

121-124

5-41

Possible defective FTU or FTU cables

If the FTU still indicates an S-C errors, call for regional support. Otherwise, repeat step 3-2 of Fault
Isolation Guide No.3 and continue from there

Possible defective Write clock - A2AO 1

11-13

Possible defective Access Control and Index/Sector
Decode card - A2B08

181-184

Possible defective Transmitters and Receivers/Head
Address Register card - A2BO 1

111-113

If the FrU still indicates an S-M error, call for regional support. Otherwise, return to step 3-2 of Fault
Isolation Guide No.3 and continue from there

Possible defective Read PLO card - A2A06

61-65

NOTE
The data switches on the FTU must be the same as
when the procedure was started.
18

Possible defective NRZ to MFM card - A2B07.

171-173

Possible defective Data Latch card - A2A05.

51-53

Possible defective Access Control No. 2 card A2A08.

81-85

Possible defective Receivers card - A2B02.

121-124

Possible defective Transmitters and Receivers/Head
Address Register card - A2BOI.

111-113

Possible defective Head Select and Read Amplifier A3A02.

261-263

Possible defective Read/Write head. Refer to Paragraph 3.32 for removal and replacement procedures.

Possible defective FTU or FTU cables.

If the FTU still indicates an Address Error, call for
regional support. Otherwise, repeat step 3-2 of Fault
Isolation Guide No.3 and continue from there.

Possible defective Read PLO card - A2A06.

61-65

Possible defective NRZ to MFM card - A2B07.

171-173

Possible defective Data Latch card - A2A05.

51-53

5-42

Possible defective Access Control No. 2 card A2A08.

81-85

Possible defective Receivers card - A2B02.

121-124

Possible defective Transmitters and Receivers/Head
Address card - A2BO 1.

111-113

Possible defective Head Select and Read Amplifier A3A02.

261-263

Possible defective Read/Write head. Refer to Paragraph 3.32 for removal and replacement procedures.

Possible defective FTU or FTU cables.

If the FTU still indicates a Data Error, call for Regional Support. Otherwise, repeat step 3-2 of Fault
Isolation Guide No.3 and proceed from there.

Attempt to clear the fault by flipping S 1 on the Fault
card - A2A04 or by hitting the Fault Switch indicator

252, 41-45

on the front panel of the drive

Determine which fault lights are on (Figure 5-7). If
the voltage fault LED (CR1) is not on, go to step 43.
Otherwise, continue with step 39 of this FIP.

Check the ±5 V on the card cage and check the ±5 V
fuses. Refer to Paragraph 5.1.2.3 for dc power distribution problems.

331-333

Check ± 12 V and ±20 V on the card cage, and check
the fuses. Refer to Paragraph 5.1.2.3 for dc power distribution problems.

321-322

Check the ±42 V plug PA09 the bottom of the card
cage. Check the ±42 V fuses.

311-312

Possible defective Fault card - A2A04. If the voltage
fault LED is still on after this card is replaced, call for
regional support. If no faults are indicated, return to
step 3-2 of Fault Isolation Guide No.3. Otherwise,
continue with this FIP.

41-44

Reverify which faults are indicated and proceed as
specified.
CR2 - Write Fault - if ON, go to step 44
CR3 - Head Select Fault - if ON, go to step 50
CR4 - Read or Write Fault - if ON, go to step 56
CR5 - Not on Cylinder and (Write or Read) - if ON,
go to step 62
Front Panel - Servo Track Fault - if ON, go to step
69
5-43

Possible defective Write card - A3A03.

271-274

Possible defective NRZ to MFM card - A2B07.

171-173

Possible defective Transmitters and Receivers/Head
Address Register card - A2BOl.

111-113

Possible defective Receivers card - A2B02.

121-124

Possible defective Interlocks and Speed Detector card
- A2AIO.

101-104

If the Write Fault LED is still on, call for regional
support. If any fault indicators are still on, return to
step 43. Otherwise, return to step 3-2 of Fault Isolation Guide No.3.

Possible defective Head Select and Read Preamp card
- A2A02.

261-263

Possible defective Transmitters and Receive~s/Head
Address Register card - A2BOl.

111-113

Possible defective Receivers card - A2B02.

121-124

Possible defective cable A.

Possible adapter problem.

If the Head Select Fault LED is still on, call for regional support. If any other fault indicators are still
on, return to step 43. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.

Possible defective Receivers card - A2B02.

121-124

Possible defective Interlocks and Speed Detector card
- A2A10.

101-104

Possible defective cable A

Possible defective Writer - A3A03.

Possible adapter problem.

If the Read or Write Fault LED is still on, call for
regional support. If any other fault indicators are still

on, return to step 43. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.

5-44

271-274

Possible defective Access Control No. 1 card A2B09.

191-193

Possible defective Receivers card - A2B02.

121-124

Possible defective Writer card - A3A03.

271-274

Possible defective Interlocks and Speed Detector card
- A2AI0.

101-104

Possible defective cable A.

Possible adapter problem.

If the Not On Cylinder And (Write or Read) LED is
still on, call for regional support. If any other fault
indicators are still on, return to step 43. Otherwise,
return to step 3-2 of Fault Isolation Guide No.3.

Possible defective Access Control No. 1 card A2B09.

191-194

Possible defective A/D Function Generator card A2A07.

71-73

Possible defective Access Control and Index/Sector
Decode card - A2B08.

181-184

Possible defective Track Servo Preamp - A3A05.

291-295

If the Servo Track Fault indicator is still on, call for
regional support. If any other fault indicators are still
on, return to step 43. Otherwise, return to step 3-2 of
Fault Isolation Guide No.3.

FIP 3-3
There is a fault on the FTU for only some (not all) addresses while the drive is doing a continuous write
format using sequential heads and sequence forward.
Print Set Page

Step
Possible defective Difference Generator Controls
card - A2B06

161-165

Possible defective D / A Function Generator card A2A07

71-73

Possible defective or worn bearings and/or carriage
rails. Call for support if bad.

5-45

FIP 3-4
Address errors occur while the drive is performing continuous read, using sequential heads and sequence forward.
Print Set Page

Step
If the address errors were not head-related, go to step
6. Otherwise, continue with this FIP.

NOTE
Th data switches on the FTU must be the same as
when the procedure was started.
2

Possible defective Transmitters and Receivers/Head
Address Register card - A2BOl.

111-113

Possible defective Head Select and Read Amplifier A2A02.

261-263

Possible defective read/write head. Refer to Paragraph 3.32 for removal and replacement procedures.

If the FTU still indicates address errors that appear to
be head-related, call for regional support. Otherwise,
return to step 3-5 of Fault Isolation Guide No.3 and
continue from there.

Possible defective Read PLO card - A2A06.

61-65

Possible defective NRZ to MFM card - A2B07.

171-173

Possible defective Data Latch card - A2A05.

51-53

Possible defective Access Control No. 2 card A2A08.

81-85

Possible defective Receivers card - A2B02.

121-124

Possible defective Transmitters and Receivers/Head
Address card - A2BO 1.

111-113

Possible defective Head Select and Read Amplifier A3A02.

261-263

Possible defective read/write head. Refer to Paragraph 3.32 for removal and replacement procedures.

Possible defective FTU or FTU cables.

5-46

FIP 3-5
Data errors occur while the drive is performing continuous reads using sequential heads and sequence
forward.
Step

Print Set Page
If the data errors were not head-related, go to step 7.
Otherwise, continue with step 2.

Ensure that the data errors are not caused by bad
spots on the disk by checking the cylinder address and
character count, along with head selected.

Possible defective Transmitters and Receivers/Head
Address card - A2BOI.

111-113

Possible defective Head Select and Read Amplifier A3A02.

261-264

Possible defective read/write head. Refer to Paragraph 3.32 for removal and replacement procedures.

If the FTU still indicates data errors that appear to be
head related, call for regional support. Otherwise return to step 3-6 of Fault Isolation Guide No.3 and
continue from there.

Possible defective Read PLO card - A2A06.

61-65

Possible defective NRZ to MFM card - A2B07.

171-173

Possible defective Data Latch card - A2A05.

51-53

Possible defective Access Control No. 2 card A2A08.

81-85

Possible defective Receivers card - A2B02.

121-124

Possible defective Transmitters and Receivers/Head
Address Register card - A2BOI.

111-113

Possible Head Select and Read Amplifier - A3A02.

261-263

Possible worn or defective carriage rails or bearings.
Call for support if bad.

5-47

FIP 3-6
The FTU indicates an error while the drive is performing random WRT.RD functions with. sequential
heads.
Step

Determine the nature of the error and proceed as indicated:
a.

For motion failures, go to step 2

For Write failures, go to step 3

For read failures, go to step 4

For head select faults or write or read faults, go
to step 5.

If the symptom of the failure is Read or Write and
(Not On Cylinder) return to the beginning of Fault
Isolation Guide No.3 and continue from there. If the
symptom is seek errors, return to the beginning of
Fault Isolation Guide No.2.

If the symptom of the failure is a Write Fault, return
to the beginning of Fault Isolation Procedure 3-1 and
continue from there. Otherwise, return to the beginning of Fault Isolation Guide No.3.

For either head select or read or write faults, go to the
beginning of Fault Isolation Procedure 3-1 and continue from there.

5-48

5.5 FAULT ISOLATION GUIDE NO.4
Will the drive power down correctly and are there no irregularities in the Power Down sequence? If
yes, refer to Figure 5-3 in Paragraph 5.1.4.2 to determine which guide should be next. If the drive will
not power down correctly, continue with this drive.
This Fault Isolation Guide assumes that the drive is powered up, and is ready with the heads loaded
and the pack spinning.

5-49

FIG 4
Step

Action

Procedure / Question

(if answer is NO)
Press the Start button. Does the Start light go out?

FIP 4-1

Do the heads unload?

FIP 4-2

Does the drive motor brake to a stop?

FIP 4-3

Attempt to open the pack access cover. Does it open?

FIP 4-4

The drive is able to power down.

FIP 4-1
The Start light does not go out when the Start button is pushed.
Print Set Page

Step
Possible defective Start switch or control panel. Refer
to Paragraph 3.16 for removal and replacement procedures.

252

FIP 4-2
The heads do not unload while the drive is attempting to power down.
Print Set Page

Step
Possible defective Access Control No. 1 card A2B09.

194

Possible defective D / A Function Generator card A2A07.

Possible defective Switching Mode Control card A2A09.

Possible defective Power Amplifier - A3A04.

282

5-50

FIP 4-3
The drive motor does not brake to a stop while the drive is attempting to power-down.
Print Set Page

Step
Check the heads loaded switch (A3S2). Refer to Paragraph 3.30 for the adjustment procedure.
Possible defective Interlocks and Speed Detect card -

103

A2AIO.

Possible defective brake - Al HB I.

Possible defective wiring harnesses.

302

FIP 4-4
The pack access cover will not open after the drive is powered down.
Print Set Page

Step
Ensure the Start switch is not pressed.

102

Possib1e defective Interlocks and Speed Detect card A2AI0.

102

Possible defective or ma1adjusted pack cover sole
noid. Refer to Paragraph 3.26 for solenoid adjustmen t procedure.

102

Possible defective cabling from card cage to pack
cover solenoid.

102

5.6

ADVANCED TROUBLESHOOTING

5.6.1 Introduction
The section is provided for the advanced troubleshooter. Information being presented here is in outline
form with less emphasis placed on procedural or FRU data. Explanations are given when applicable
and outlines of procedural listip.gs are provided.
5.6.2 DCK and ECH Error Descriptions
A data check error is a read error; the 32-bit ECC word calculated and written when the 256 data
words were written on the disk does not agree with the 32-bit ECC word calculated when the 256 data
words are read from the disk. A DCK can only occur during the following commands.
1.

2.
3.
4.

Read Head and Data
Read Data
Write Check Header and Data essentially disk read operations
Write Check Data.

5-51

The Error Correction Code (ECC) is a hardware/software feature that may be used (if bit 11 of the
RMOF is reset) to attempt to correct bad data read from the disk without actually performing another
read operation. The sequence is as follows. After reading a sector and the DCK bit is set and the ECI
bit is reset, the ECC circuits in the MBA will automatically perform a cycling operation to determine
which bits in the sector data area were picked up or dropped, and where those bits are located in the
sector. This feature is limited to 11 consecutive bits. At the completion of the ECC cycle either of two
things happen.
1.

If the bits picked up or dropped are within 11 consecutive bits of each other, the ECC
pattern register is equal to the II-bit burst of bad data bits (a one in the register corresponds
to a bad bit, a zero is a good bit) and the ECC position register is equal to the number of bits
into the 256-word data area that the bad II-bit burst begins. It is now up to the software to
read these registers and to go into the memory location(s) determined from the original
RMBA register value and the value in the ECC position register and perform a Bit Complement instruction using the value in the ECC pattern register.

If the bits picked up or dropped in the 256-word data area are not within 11 consecutive bits
of each other, ECH is set (bit 6 of RMERl). At this point the software must attempt to
execute another read command in order to recover the data in that particular sector.

NOTE
It is particularly advantageous to use the ECC feature because an ECC cycle (not including the software calculation time) takes approximately 7 ms as
opposed to waiting 16.6 ms per full disk revolution in
order to reread the sector.
5.6.3 Data Check Fault Isolation Guide
This Fault Isolation Guide is designed like Guide No.1 through No.4, with the referenced Fault
Isolation Procedures (FIPs) appearing after the Guide itself.
Step

Procedure / Question

Action (if answer is NO)

DC-l

Check to see if Data Check is true. If it is true, have
the heads not crushed

DC-7

DC-2

The heads have crashed. Determine the history of the
packs on that site that have been used on the drive in
question.

DC-3

Set aside all suspect packs for inspection.

DC-4

Clean the shroud area of each disk and inspect all
heads on other drives for contamination. Clean as
needed.

DC-5

On drive in question, replace and align heads as necessary. Refer to Paragraph 3.32 for these procedures.

DC-6

Check the drive for compatibility and run the appropriate diagnostics.

5-52

DC-7

Is DCK true for more than one head?

FIP-DCl

DC-8

Is DCK occurring on a large number of cylinders?

FIP-DC2

DC-9

Are there no intermittent LBCs, SKIs or HCEs with
the DCK?

FIP-DC3

DC-I0

End.

FIP DCI
DCK is true on only one head.

Print Set Page

Step
Replace or align head. Refer to Paragraph 3.32 for
pro cedures.

Reformat the pack. (This is not necessary if the head
alignment is done correctly.)

Possible defective Head Select and Read Amplifier A3A02.

261-263

Possible defective Writer - A3A03.

271-274

Possible defective pack.

FIP De2
DCK occurs on a small number of cylinders.

Print Set Page

Step

Possible defective Writer - A3A03.

271-274

Possible defective NRZ to MFM card - A2B07.

171-173

FIP DC3
DCK occurs with intermittent LBCs, SKIs or HCEs.

Step

Print Set Page
Possible defective Track Servo Preamplifier - A3A05.

291-292

Possible defective Fine Servo Decode - A2A03.

31-35

Possible defective Write Clock - A2AOI.

11-13

Replace and realign servo head. Refer to Paragraph
3.32 for these procedures. Note that realignment of
the servo head requires realignment of all the other
heads as well.

5-53

5.6.4 Error Tests
The following routine may be used to RUN LOOP on error or HALT on error tests.
DZQUD-E 25-FEB-76 RKDP-XXDP RKII MONITOR 24K
RESTART ADDR: 132522
BOOTED VIA U
R UPD2
DZQUB-I 25-FEB-76-XXDP UPDATE PROGRAM #2
DATE: 8-JAN-78
8-JAN-78
PROGRAM RELOCATED TO: 100764
RESTART: 105116
*LOAD DKO:RMULTI.BIN
XFR:OOOOOI CORE:000050,007501

:LOC
MOD200
000200
000202
(GET COMM)
000204
000206
000210
000212
000214
000216
000220
000222
000224
000226
000230
000232
000234
000236*
000240
000242
000244*
000246
000250
000252
000254
000256
000260
000262
000264
000266
000270
000272
000274
000276
000300
000302
000304

1004

;LOAD UNIT NO. INTO LOC 1004

013727
177570

MOV CONTENTS OF S.R. INTO LOC 204

000000
00000o
000240
012737
177400
176702
012737
002000
176704
013737
001004
176710
012737
000000
176706
012737
000000
176734
013737
000204
176700
000137
000100
000240
032737
040000
176700
001001
000411
005737
177570
100331

;HALT
;NOOP
MOV 177400INTOW.C.
MOV 2000 INTO B.A.
MOV CONTENTS OF 1004 INTO CS2
LOAD CONTENTS OF LOC 236 INTO D.A.
LOAD CONTENTS OF LOC 244 IN D.C.
LOAD CONTENTS OF LOC 264 INTO CS 1
JUMP TO LOC 100

()()()()()()

5-54

000306
000310
000312
000314
000316
000320
000322
000324
000326
000330
000332
000334
000336
000340
000342
000344
000346
*MODl00
000100
000102
000104
000106
000110
000112
000114
000116
000120
000122

012737
000040
176710
000137
000212
132737
000200
177570
001002
000137
000212
00000o
000137
000212
00000o
00000o
00000o
105737
176700
100375
105737
176712
100375
000137
000264
00000o
O()()()()()

IF NO ERRORS AND S.R.(7) = 1 = HALT
IF NO ERRORS AND S.R.(7) = 0 = LOOP

IF AN ERROR AND S.R.(15) = 1 = HALT
IF AN ERROR AND S.R.(15) = 0 = LOOP

TEST CSI ROY BIT
READY? IF YES ;IF NO
TEST DS READY BIT
JUMPT0264

5-55

RM02/03 Disk Subsystem
Service Manual
EK-RM023-SV-001

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