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EK-RX012-PS-002

November 1981

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Document:	RX01/RX02 Pocket Service Guide
Order Number:	EK-RX012-PS
Revision:	002
Pages:	56
Original Filename:

OCR Text

E K-R XO12-EO02

RXOI / RX02
Pocket Service Guide

digital equipment corporation 0 maynard, massachusetts

1st Edition, November 1980
2nd Edition, September 1981

Copyright 0 198 1
by Digital Equipment Corporation.
All Rights Reserved.
The reproduction of this material, in part or
whole, is strictly prohibited. For copy information, contact the Educational Services
Department, Digital Equipment Corporation,
Maynard, Massachusetts 0 1754.
The information in this document is subject
t o change without notice. Digital Equipment
Corporation assumes no responsibility for
any errors that may appear in this document.

Printed in U.S.A.

The following are trademarks of Digital
Equipment Corporation, Maynard, Massachusetts.
DECnet
DEC
DECsystem-10
DECUS
DIGITAL
DECSYSTEM-20
Digital Logo DECwriter
PDP
DIBOL
UNIBUS
EduSystem
VAX
IAS
MASSBUS

OMNIBUS
OS/8
PDT

RSTS
RSX
VMS
VT

CONTENTS
1

TROUBLE SHOOTING

1.1
1.2
1.3
1.4
1.4.1
1.4.2
1.4.3

1.5
1.5.1
1.5.2
1.5.3
1.6
1.6.1
1.6.2
1.6.3
2

MECHANICAL SERVICING

2.1
2.2
2.2.1
2.2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.9.1
2.9.2
2.10
2.1 1

General ................................
1
Troubleshooting Charts ................... 2
Power Supply Voltages ................... 8
RXWRX28 Subsystem ................... 9
Bootstrap ............................
13
Registers .............................
13
Interface (M8357) ....................
15
RXl l/RXVll Subsystem ................ 15
Bootstrap ............................
16
Registers .............................
16
Interfaces (M7846 and M7946) ........ 18
RX211/RXV21 Subsystem ............... 18
Bootstrap ............................
20
Registers .............................
20
Interfaces (M8256 and M8029) ........ 20

General ................................
25
RXOl/RXO2Disk Drive Assembly ........ 26
Rack-MoUt ..........................
26
Case-Mount ..........................
27
Controller Board .........................
29
Read/Write Board .......................
30
Drive ...................................
32
Power Supply ...........................
35
Power Board Assembly (Regulators) ....... 36
Drive Belt and AC Motor Pulley .......... 37
Door Handle ............................
38
Door Handle Removal ................ 38
Door Handle Installation .............. 38
Read/Write Head ........................
39
Stepper Motor Lead Shaft ................ 39

iii

CONTENTS

ALIGNMENT AND ADJUSTMENT

3.1
3.2
3.3

Handle Latch Wire ......................
41
Drive Belt and AC Motor Pulley .......... 41
Head Gap ..............................
43

APPENDIX A

SPARE PARTS LIST

FIGURES
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
1-10
1-11
1-12
2- 1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-1 1
2-12
3- 1
3-2
3-3
3-4
3-5

What SystedSubsystem Is This? ......... 3
Diskette Media ..........................
4
Head Plug (P3)to M7727 ................ 7
Power Supply Voltage Checks ............. 9
RX8/RX28Registers ....................
4
M835 7 Interface (RX8IRX28) ............ 16
RX1 I/RXVll Registers ................. 17
M7846 Interface ( R X l l ) ................. 18
M7946 Interface (RXVl 1) ............... 19
Rx211/RXV21 Registers ................ 21
M8256 Interface (RX211) ................ 23
M8029 Interface (RXV21) ............... 24
Subassembly Removal and Replacement .... 25
Removing and Replacing RXOl/RXO2
27
(Case-Mount) ...........................
Controller Board Connections ............. 28
R X O l Read/Write Board Connections ..... 30
RX02 Read/Write Board Connections ..... 31
PlenudFan Assembly ................... 33
Drive and Power Supply Removal ......... 34
Power Supply Components ............... 35
Capacitor C1 and C2 Connections ......... 36
Drive Belt and AC Motor Pulley .......... 37
Door Handle Assembly .................. 39
Head Camage Components (Top View) .... 40
Motor Pulley Alignment .................. 41
Underside View of Drive ................. 42
Head Gap Adjustment ................... 43
R X O 1 Pressure Pad Mechanism
(Front View) ............................
44
RX02 Pressure Pad Mechanism
45
(Front View) ............................

CONTENTS

TABLES
1-1

1-2
1-3
1-4
1-5

1-6
1-7
1-8

1-9
1-10

2- 1

Reference Documentation ................. 1
RXOl/RXO2 Field Replaceable Units ..... 2
RXOl/RXO2 Troubleshooting Chart ....... 3
7
Intermittent Problems ....................
Voltages ................................
8
Diagnostic Error Code Definitions and
Probable Causes .........................
10
Diagnostic Printout Troubleshooting
Chart ...................................
12
RX8/RX28 Bootstraps ................... 13
RXl l / R x V l l Bootstrap ................. 16
RX2 1 1/RXV21 Bootstrap ................ 20
Switch Configuration for MI744 .......... 29

TROUBLESHOOTING

1.1 GENERAL
This chapter summarizes information on the disk drives,
interface boards, and diagnostics for the RXOl /RX02
subsystem. For additional information, refer to Table 1-1
for a list of appropriate documents.

NOTE
PDT floppy drives are not included in this
document. Refer to the PDT Pocket Service
Guide.
Table 1- 1 Reference Documentation
Title

Order Number

RXOl/RXOZ Pocket Service Guide
RXOI/RXO2 Reference Card
RX01/08/11 Maintenance Manual
RX02 Floppy Disk System Technical
Manual
RXVRXl 1 RXOl Floppy Disk System
RX02 Floppy Disk System Users Guide
RXVl 1 Users Guide
RXOl/RXO2 Customer Equipment Ci-e
R X O l Floppy Disk IPB
RX02 Floppy Disk IPB
70-1 3077 Drive IPB
H771 Power Supply IPB

EK-RXOl2-PS
EK-RXI 02-RC
EK-ORXOI -MM
EK-ORXO2-TM
EK-ORXOl-OP
EK-ORXO2-UG
EK-RXVI 1-OP
EK-RXOl2-EC
EK- ORXO 1-1P
EK- OFZO2-IP
EK-13077-IP
EK-OH77 1-IP

TROUBLESHOOTING

The RXOl/RXO2 subsystem is made of seven field replaceable units (FRUs) plus the chassis and cables. The
FRUs and their functions are listed in Table 1-2.
The RXOI/RXOZ may be in one of several types of
subsystem configurations. Figure 1-1 diagrams the most
popular configurations.
Parts commonly used in the RXOl/RX02 are listed in
the Spare Parts List i n Appendix A.

1.2 TROUBLESHOOTING CHARTS
Table 1-3 lists the most common failures, their symptoms, and their remedies. Table 1-4 lists intermittent
problems that can occur.

NOTE
When troubleshooting, always have the customer duplicate the problem if possible.
Always check all connections before servicing
any board or other assemblies.
Table 1-2 RXOlIRX02 Field Replaceable Unit9
FRU

Function

Drive assembly

Does electromechanical handling of the
diskette.

Readwrite board

Transfers data, decodes/encodes data,
selects drive, controls head positioning.

Controller board

Decodes commands from host and initiates functions.

Interface board

Converts bus signal levels to RX compatible levels. Controls interrupts and transfers commands and data.

Power supply
(includes regulator
board)

Steps down ac line voltage. Converts ac
to dc. Regulates dc. Outputs ac to drive;
outputs dc to reauwrite and controller
boards.

Regulator board

Regulates dc voltages. Outputs dc to
readwrite and controller boards.

Plenudfan
assembly

Cools RXOl/RX02 assembly.

* See Appendix A for part numbers.

TROUBLESHOOTING
DISC DRIVE

RXOl

RX02

CONTROLLER
BOARD

M7726

M7744

READWRITE
BOARD
INTERFACE

M83r

M 7 r

RX8i

RXjll

BOARD

M7rI i l
M8357

M8029

M8256

RX28

RXVZI

RX211

RXll

SUBSYSTEM
BUS

OMNIBUS

SYSTEM

PDP4

LSIBUS

LSI 11

.,i""

PDP-11

OMNIBUS LSlBUS

PDP4

LSI-11

UNIBUS

PDP.11

NOTE
781278 systems are no1 mcluded
.
I
.
.
,
.
,

Figure 1-1 What System/Subsystem Is This?

Table 1-3 RXOl/RXO2 Troubleshooting Chart
~

Symptom

Possible Cause

Remedy

Door handle
not latching
properly

Latch wire

Adjust handle latch
wire (Paragraph 3.1).

Handle release
button

Install headed-pin
pivot (P/N 74-21076).
Replace door handle.

Both drives
inoperative,
fan not turning
(no indication
of power)

Power cord

Check power cord and
ac input

AC power fuse

Replace ac power fuse

or circuit breaker

(2.0A) or reset circuit
breaker.

NOTE
To check if diskette (Figure 1-2)is turning, align
index hole in diskette with hole in cover. Place in
drive and close cover. Then, remove diskette. If
holes are stilt aligned, diskette is not turning.

TROUBLESHOOTING

Table 1-3 RXOl/RXO2 Troubleshooting Chart (Cont)
Possible Cause

Symptom

Remedy

INDEX HOLE APERTURE

Gb
JACKET
SEAMS

REGISTRATION
HOLE

ENVELOPE
READNVRlTE
‘HEAD I(PERTURE

“.,sa.

Figure 1-2 Diskette Media
Diskette not
turning

Belt

Replace belt
(Paragraph 2.8).

Drive power plug

Check plug connection
to drive (Figure (2-7).

Power supply

Check voltages
(Paragraph 1.2).

Drive motor
‘

Both drives fail
to initialize

Replace drive
(Paragraph 2.5).

Host

Make sure host is interacting with other YO
devices.

Interface/
interface cable

Check connection and
polarity of cable with
host
Replace interface cable.

Power supply

Check voltages
(Paragraph 1.2).

TROUBLES HOOTlNG

Table 1-3 RXOl/RXOZ Troubleshooting Chart (Cont)
Symptom

Possible Cause

Remedy

Configuration
(RX02 only)

Set switches on
controller board to
correct position
(Table 2-1).

Interface board

Replace interface board

CAUTION
Do not shortout aboard. When checking read/write
or controller board, place insulating material on
top of existing board and temporarily cable board
in place. Remove board only when verified as
faulty.

One drive fails
to initialize

Controller board

Replace board
(Paragraph 2.3).

Readwrite board

Replace board
(Paragraph 2.4).

Drive power
connector

Check connector
(Figure 2-7).

NOTE
In the RX02 unit, interchange all cables of drives 0
and 1 (Figure 2-5). If symptom appears on other
drive, substitute boards to determine defective
board (Paragraphs 2.3 and 2.4). If symptom remains on original drive, replace drive mechanism
(Paragraph 2.5).
Readwrite board

Replace board
(Paragraph 2.4).

Readwrite to
controller cable

Replace cable.

Controller board

Replace board
(Paragraph 2.3).

Drive

Replace drive
(Paragraph 2.5).

TR 0UBLES HOOTlNG

Table 1-3 RXOI/RXOZ Troubleshooting Chart (Cont)
Symptom

Possible Cause

Remedy

NOTE
Diagnostics should boot in drive 0 and 1 of unit A.
Host software may not.
Program cannot Diskette
be booted or
run from either

Replace diskette.

Controller board

Replace board
(Paragraph 2.3).

Interface cable

Replace cable.

Readwrite board

Replace board
(Paragraph 2.4).

Readwrite to
controller cable

Replace cable.

Readwrite board

Replace board
(Paragraph 2.4).

Drive

Replace drive
(Paragraph 2.5).

Diagnostic

Use correct diagnostics
(Paragraphs 1.3
through 1.5).

Load error

Reload diagnostic using
second drive.

Controller board

Replace board
(Paragraph 2.3).

Interface board

Replace interface.

Interface cable

Replace cable.

Diagnostics
run with errors

Subsystem

Look up errors in
Tables 1-6 and 1-7.

Diagnostics
run okay but
intermittant
errors persist

Subsystem

Go to Table 1-4.

drive.

Diagnostics
boot in one
drive only

Diagnostics
boot but will
not run

TROUBLESHOOTING

Table 1-4 Intermittent Problems
Symptom

Possible Cause

Remedy

Errors with
readwrite data
functions

Readwrite head
plug (P3)

Install resistor assembly
(P/N 70-16263). The
resistor assembly must
always be installed
when using M7726 and
M7727 boards (Figure
1-3).

H F A n PI IIC: P7

WHITE

BLACK

M U S T H A V E RESISTOR I N S T A L L E D

D R I V E USED WITH M 7 7 4 5 MUST
N O T H A V E RESISTOR

Figure 1-3 Head Plug (P3) to M7727

Seek errors

Diskettes do
not recopy but
appezr okay

Metal read/write
head

If subsystem has one
drive with a metal head
and one with a ceramic
head, replace drive with
metal head.

Stepper motor
lead shaft

Clean shaft with
alcohol and regrease
(Paragraph 2.1 1).

Stepper motor
burning etch

Stepper motor can
cause burning or discoloration around transistors in rear comers of
board Replace drive and
readwrite board.
(Paragraphs 2.4
and 2.5).

Faulty write
current

Replace readwrite
board (Paragraph 2.4).
Replace controller
board (Paragraph 2.3).

Any symptom

Interface cable

Reinsert cable.

TROUBLESHOOTING

Table 1-4 Intermittent Problems (Cont)
Symptom

Possible Cause

Remedy

Any symptom

Interface cable

Replace cable.

Controller to
readwrite cable

Reinsert cable.
Replace cable.

Connectors
P3 through P7
(Figures 2-4 and
2-5)

Hold-down screw
shorting to board

Reinsert connectors.
No brass Female ends
should push out of
plastic plugs.
Install nylon washers on
any hold-down screw
near the board etch.

1.3 POWER SUPPLY VOLTAGES
Use Table 1-5 and Figure 1-4 for all dc voltage checks.
There are no adjustments. If voltages are incorrect, replace the power board (Paragraph 2.7) or the power s u p
ply (Paragraph 2.6).

Table 1-5 Voltages*
Pin

Voltage

Purpose

Connection FQ to J4/J3 (power board to controller board)
1
2

f9.5 Vdct

3
4

+5 Vdc

5
6

Initializes
No connection
Ground
Powers logic signal
Ground
No connection

Connection P1 and J2 (power board to read/wfite board)
1
2

-5 Vdc

3
4

5
6

+5 Vdc
0.v
+24 Vdc

No connection
Powers analog IC
Ground
Powers logic signal
+24 V return
Powers stepper motor, erase and write
current, head-load solenoid

* Use with Figure 1-4.
t Some documents wrongly state 10 V

TROUBLESHOOTING

IORANGEI +9.5V P2-1

IBLACKIGRD

IRX021 J:
I R X O l I JL

IBLUEI -5V P1-2
IBLACKI G R D
YfREDIr5V

-\1RED2
’4V

Plb

P1 4

Figure 1-4 Power Supply Voltage Checks

1.4 RX8/RX28 SUBSYSTEM
Use this information for diagnostics, installations, and
troubleshooting. Table 1-1 lists documents with additional information. The RX8/RX28 subsystem has two diagnostics.

AIRXA(x) functional test
AIRXB(x) performance exerciser*
Make sure the revision level of the diagnostic and diagnostic writeup are the same. Tables 1-6 and 1-7 are for
use with diagnostic error printouts.
*The symbol ( x ) represents the revision level.

TROUBLESHOOTING

Table 1-6 Diagnostic Error Code Definitions and Probable
Causes
Code

Definition

Causes

0010

Drive 0 failed to see home
on initialize.

Drive
Controller
WW electronics

0020

Drive 1 failed to see home
on initialize.

Drive
Controller
WW electronics

003P

Found home when stepping
in 10 tracks for init

Drive
Controller
WW electronics

0040

Tried to access a track
greater than 76 (decimal).

Interface module
Controller

0050

Home was found before
desired track was reached.

WW electronics
Drive
Controller

006P

Self diagnostic error (Init).

Controller
Cables
Interface module

0070

Desired sector not found
after looking at 52 headers
(2 revolutions).

Diskette
WW electronics
Drive
Controller
Interface module

010P

Write command on a
write-protected drive.

WW electronics
Controller

01 10

More than 40 ps and no
SEP clock seen.

Diskette
WW electronics
Drive
Controller

0120

A preamble not found.

Diskette
WW electronics
Drive
Controller
Power supply
Interface module

0130

Preamble found but no ID
mark found in time.

Diskette
WW electronics
Controller

TROUBLESHOOTING

Table 1-6 Diagnostic Error Code Definitions and Probable
Causes (Cont)
Code

Definition

Causes

014P

CRC error on a header but
error not asserted.

Controller
Cables
Interface module

0150

Good header track address
does not compare with
desired track

R/W electronics
Drive
Controller

0160

Too many tries for an

WW electronics
Drive
Controller

IDAM (identifies header).
0170

Data AM not found in time.

Diskette
R/W electronics
Controller

0200

CRC error on reading the
sector from disk. No code
appears in ERREG.

Diskette
WW electronics
Controller

021P

Parity error on a word from
VF to controller.

Controller
Interface module
Cables

0220 t

WW electronics failed
maintenance mode test.

WW electronics
Controller

0230t

Word count overflow.

Interface module
Controller

0240t

Density error.

Diskette
Controller
Interface module
R/W electronics

0250t

Wrong key word for set
media density command.

Interface module
Controller

* RXOl only

t RX02 only

TROUBLESHOOTING

Table 1-7 Diagnostic Printout Troubleshooting Chart
Symptom

Possible Cause

Remedy

Done bit
timeout

Configuration
(RX02 only)

Set switches(Table2-I).

Interface board

Replace board

Controller board

Replace board
(Paragraph 2.3).

Interface board

Replace board

Diskette

Replace diskette.

Controller board

Replace board
(Paragraph 2.3).

Readwrite board

Replace board
(Paragraph 2.4).

Controller board

Replace board
(Paragraph 2.3).

Interface board

Replace board

NPR jumper

Cut jumper on PDP- 1 1
backplane F X ?1 1.

Interface board

Replace board

Controller board

Replace board
(Paragraph 2.3).

Interface board

Set switches correctly.

TR bit timeout

Set density
error

Data error but
no CRC error

Fill buffer

error
Empty buffer
error

Unexpected
interrupt to
location XXX

Replace board

TROUBLESHOOTING

1.4.1 Bootstrap
When a front panel is available, use toggle-in routines
(Table 1-8) to boot the floppy.
1.4.2 Registers
The RX8/RX28 registers are broken down in Figure 1-5.
Table 1-8 RX8/Rx28 Bootstraps
~~

RX8

RX28

Location

instruction

Location

Instruction

24
25
26
27
30

7126
1060
67x1
720 1
405 3

20
21
22
24

1061
1046
0060
306 1
7321

31
32
3 3 (START)
34
35

405 3
7104
67x5
5054
67x4

25
26
27
30
31

1061
67x1
7301
405 3
405 3

36
37
40
41
42

7450
7610
5046
1060
704 1

32
33 (START)
34
35
36

7004
67x5
5054
67x4
7450

43
44
45
46
47

1061
3060
5024
67x1
405 3

37
40
41
42
43

5020
1061
67x1
1061
0046

50
51
52
53
54

3002
2050
5047
67x3

44
45
46
47
50

1032
3060
0360
405 3
3002

5033
67x2
5453
7024
6030

51
52
53
54
55

2050
5047

oooo

56
57
60
61

67x2
5453
0420
0020

55
56
51
60
61

OOOO

67x3
5033

TROUBLESHOOTING
COMMAND AND STATUS REGISTER

FUNCTION

FUNCTION CODES
000 F I L L BUFFER
001 EMPTY BUFFER
010 WRITE SECTOR
011 READ SECTOR

100 NOT USED (RXO1)
SET DENSITY (RX02)
101 READ RXES
110 WRITE WITH DEL DATA MARK
111 READ ERROR REG

ERROR AND STATUS REGISTER (StatusA)

DRV
RDY

WRT
PROT
ERR

PAR
ERR

DRV
RDY

Figure 1-5

DRV
DEN

RX02

RXBIRX28 Registers (Sheet I of 2)

CRC
ERR

TROUBLESHOOTING

T R A C K A D D R E S S REGISTER
RXTA, RXZTA, PDP-8, RX01/02

67x2

TRACK ADDRESS 0 1 1 4 8

D A T A B U F F E R REGISTER
RXDB, PDP8. RXOl/RX02

DATA. 12 BIT
MODE ONLY

67x2

DATA BYTE
I
I
k

SECTOR A D D R E S S REGISTER

Figure 1-5

SECTORAODRESS 132.
1

RX8/RX28 Registers(Sheet 2 of 2)

1.4.3 Interface (M8357)
Use the M8357 board (Figure 1-6) for both RXOls and
RX02s when they are connected to PDP-8systems. Device code switch settings are the same whether the interface is on an RX8 or RX28 subsystem.

NOTE
RXOlIRX02 interfacing to 781278 series computers is part of the CPU.
1.5 R X I l / R X V l l SUBSYSTEM
Use this information for diagnostics, installations, and
troubleshooting. Table 1-1 lists documents with additional information. The RXI 1 /RXVl 1 subsystem has two
diagnostics.

ZRXA(x) system reliability test
ZRXB(x) interface diagnostic*
Make sure the revision level of the diagnostic and diagnostic writeup are the same. Use Tables 1-6 and 1-7
with error printouts.
*The symbol (x) represents the revision level

TROUBLESHOOTING

INTERFACE MODULES
RX8 & RX28 WBJ57)

3 % s4 % % % %

DEVICECODE ‘1

____.

ITp

NOT
CONNECTED

0-OFF

RED STRIPE

0 0

BERG CONNECTOR

DEVICE CODE

SWITCH
LATCH

Figure 1-6 M8357 Interface (RX8/RX28)

1.5.1 Bootstrap
When a front panel is available, use a toggle-in routine
(Table 1-9) to boot the floppy.

1.5.2 Registers
The R X l l / R X V l 1 registers are broken down in Figure
1-7.
Table 1-9 RXl l/RXV11 Bootstrap

Location

Instruction

Location

Instruction

1000
1002
1004
1006

005000
012701
177170
105711
001776
01271 1

1022
1024
1026
1030
1032
1034
1036
1040
1042

100405

1010

1012
1014
1016
1020

000003
00571 1
001 776

10571 1

loo004
116120
000002
000770
000000

005000
000110

TROUBLESHOOTING

ERR I N l T

FUNCTION

FUNCTION CODES

OW F I L L BUFFER

100 NOT USED I R X O l l

001 EMPTY BUFFER
010 WRITE SECTOR
011 READSECTOR

SET DENSITY IRX021
101 READ RXES
1lOWRlTE WITHOELDATAMARK
111 READ ERROR REG

E R R O R AND STATUS REGISTER (Status A I
RXES. PDP-llILSI-11, RXOl

177172

DRV
ROY

WRT
PROT
ERR

PAR
ERR

SECTOR ADDRESS REGISTER
RXSA. PDP-11iLSI-11. RXOliO2

177172

m 08

03 02 01 00
SECTORADDRESS
,
, 13Z8 ,

TRACK ADDRESS REGISTER
RXTA. PDP-11ILSI-11. RXOIiOZ

177172

TRACKADDRESS
,
0114 I

DATA BUFFER REGISTER
RXDB. POP 11iLSI-11
15

177172
11

UL-O,.~

Figure 1-7 RXI I/RXVI 1 Registers

TROUBLESHOOTING

1.5.3 Interfaces (M7846 and M7946)
The M7846 ( R X l l ) and M7946 ( R X V l l ) boards work
with RXOls and RX02s set for singledensity use. Figures 1-8 and 1-9 give normal bus and vector addresses.

1.6 RX211/RXV21 SUBSYSTEM
Use this information for diagnostics, installations, and
troubleshooting. Table 1-1 lists documents with additional information. The RX21 I/RXVZl subsystem has four
diagnostics.

REMOVED 0
INSTALLED 1

]

TROUBLESHOOTING

ZRXD(x) RX02 performance exerciser
ZRXF(x) RX02 function/logic
ZRXC(x) RX02 utility driver (Brutus)
ZRXE(x) RX02 formatter program*
Field Service requires ZRXD and ZRXF only. ZRXC
is primarily an engineering tool. ZRXE sets media density only and does not write headers. Make sure the revision level of the diagnostic and diagnostic writeup are
the same. Use Tables 1-6 and 1-7 with error printouts.

BUS
ADDRESS

1p-

INSTALLED

nlT
0-RXCS
1 RXOB

NORMAL
OTHER
12701

ETCH REV 8 MACHINE INSERTED JUMPERS

ETCH REV C WIRE WRAPJUMPERS

".,/,>.

Figure 1-9 M7946 Interface (RXVI 1 )

*The symbol (x) represents the revision level.

TROUBLESHOOTING

1.6.1 Bootstrap
When a front panel is available use a toggle-in routine
(Table 1-10) to boot the floppy.
1.6.2 Registers
The RX2l I/RXV2I registers are broken down in Figure
1-10.
1.6.3 Interfaces (MS256 and M8029)
Use the M8256 (RX21 I ) and MS029 (RXV21) boards
with RX02s only. Figures 1-1 1 and 1-12 show normal
bus and vector addresses.
Table 1-10 RX211/RXV21 Bootstrap
~~

Location

Instruction

Location

Instruction

2000
2002
2004
2066
2010

012701
177170
012700
100240
005002

2060
2062
2064
2056
2070

000304
03001 1
001776
100422
01271 1

2012
2014
2016
2020
2022

012705
000200
012704
00040 1
012703

2072
2074
2076
2100
2102

000403
03001 1
001776
100415
010513

2024
2026
2030
2032
2034

177172
03001 1
001776
100440
01271 1

2104
2106
21 10
21 12
21 14

03001 1
001 776
100411
010213
060502

2036
2040
2042
2044
2046

000407
03001 1
001776
100433
110413

21 16
2120
121 1
2124
2126

060502
122424
120427
000007
003737

2050
2052
2054
2056

000304
03001 1
001776
110413

2130
2132
2134

005000
005007
000000

TROU BLESHOOTl NG

ERR INIT E X T A D D

FUNCTION

RX02

UNIT
SEL

INT
ENB

W1 EMPTY BUFFER
OlOWRlTESECTOR
01 1 READ SECTOR
1W NOT USED IRXO1)
SET DENSITY (RXOZI

l l O W R l T E WITH DEL OATAMARK
111 READERROR REG

WC
OVFL

UNIT
SEL

DEL
DATA

DEN

ERR

INlT
DONE

CRC
ERR

SECTOR A D D R E S S R E G I S T E R
RXZSA. PDP-l1/LSI.11

RXOllO2

177172

SECTOR ADDRESS
132,

T R A C K ADDRESS REGISTER
RXZTA. PDP~111LSI-Il RX01102

177172

o
~

TRACK ADDRESS
0114,
VA.

Figure 1-10

RX211/RXV21 Registers (Sheet 1 of 2)

95.9

TROUBLESHOOTING

WORD COUNT REGISTER
RX2WC. P D P ~ l l I L S I ~ IRX02
l.
ONLY

177172

o
WORD COUNT
0 1w. IS01
0

m.IDDI

BUS ADDRESS REGISTER
RXZBA, PDP 11ILSI-11. RX02 ONLY
15

177172

ERROR CODES

I I:!:

DV DEN HD DEN
SEL DV1 LD DV

TRACK ADDR SEL DV
TARGET SECTOR

TARGET TRACK

CURRENTTRACK D V l

CURRENTTRACK DVO

WORD COUNT REG
15

ERROR CODE
8

Figure 1-1 0

WORD4

WORD 1
0

R x 2 11/RXV2 1 Registers (Sheet 2 of 2)

*. I . O

TROUBLESHOOTING

OFF

@
OFF-0

PRIORITY
PLUG

VECTOR
SWITCH
I
.
3l.X

Figure 1-1 1

MS256 Interface (RXZI 1)

TROUBLESHOOTING

11772WI

0-RXCS
1-RXDB

INSTAL LED
JUMPER NO.

$z:SS

~ 1 5 ~ ~ 1 ~ v 1 3 ~ V 1 2 ~V91
v l Il V~8V lV71
O ~V 6 ( V51 V4 1V31V21
NORMAL
OTHER
12701

REMOVED 0
INSTALLED = 1

BC05L
CABLE
CONNECTION

BUS
ADDRESS
JUMPERS

VECTOR
ADDRESS
JUMPERS

Figure 1-12 MS029 Interface (RXV21)

1.11.(31

MECHANICAL
SERVICING

2.1 GENERAL
This chapter describes the removal, replacement, and
cleaning of RXOl /RX02 assemblies, boards, and field
replaceable components. Figure 2-1 shows the order in
which units must be removed and provides convenient
references to the appropriate paragraphs.
WARNING
Before attempting to remove or replace any assemblies, disconnect all power plugs and interface cables.

n
DRIVE
ASSEMBLY
PAR 2.2

SUPPLY
PAR 2.6

DRIVE BELT
& AC MOTOR
PULLEY
PAR 2.8

BOARD

DRIVE 1

DRIVE 0
PAR 2.5

Figure 2-1 Subassembly Removal and
Replacement
25

MECHANICAL SERVICING

2.2 RXOl/RXO2 DISK DRIVE ASSEMBLY
Use the following procedures to remove the entire disk
drive assembly from a system. Paragraph 2.2.1 applies to
an RXOl/RX02 mounted in a rack, and Paragraph 2.2.2
applies to an RXOl /RX02 mounted in a case.
NOTE
Some RXOls and RX02s are mounted in other
type cabinets. Refer to the appropriate system
documentation in these cases.

2.2.1 Rack-Mount
Perform the following procedure to remove and install a
rack-mounted RXOl /RX02.
WARNING
Disconnect the power cable from the prime
power source and the interface cable from the
host before attempting to remove the
RXOl/RX02.
The disk drive assembly weighs approximately
65 pounds. Lifting the unit requires two people
to avoid personal injury or equipment damage.
1. Disconnect power to the system.
2. Slide unit so that it is extended in the rack.

3. Disconnect the ac power cord from the host system.
4. Disconnect the interface cable from the interface
board.

5. Remove any cable clamps holding the interface
cable.
6. Carefully remove the RXOl/RXO2 from the rack
by pressing in on the stop tabs. In some versions,
eight screws on the side rails must be removed first.
7. Install the RXOl /RX02 assembly by reversing
steps 1 through 6.

MECHANICAL SERVICING

2.2.2 Case-Mount
Perform the following procedure to remove and install’a
case-mounted RXOI/RX02. Refer to Figure 2-2.

WARNING
Disconnect the power cable from the prime
power source and the interface cable from the
host before attempting to remove the
RXOlIRX02.
The disk drive assembly weighs’ approximately
65 pounds. Lifting the unit requires two people
to avoid personal injury or equipment damage.
1. Disconnect the power and interface cables from the

rear of the RXOI/RX02 (Figure 2-2).
2. Remove mounting screws if present.
3. Slide the unit from the mini-desk.
NOTE
When replacing the unit in the mini-desk, brace
the desk against the wall to prevent it from rolling.

COVER

SCREWS
IBOTH SIDESI

PLUG

CABLE

Figure 2-2 Removing and Replacing
RXOl /RX02 (Case-Mount)

MECHANICAL SERVICING

4. Turn the two cover-locking screws on the back of

the unit 1/4-turn counterclockwise (Figure 2-2).
5. Slide the top cover backwards and lift it straight
UP.
6. Remove the four case-mounting screws on each side
of the case (Figure 2-.2).

7. Remove the ac plug from the receptacle in the rear
of the case.
8. Remove the three screws securing the controller to
the chassis. Note the position of any nylon washer.
Swing the board upright. Remove connector J 1 of
the interface cable from the controller board (Figure 2-3). Swing the board down.
9. Slide the chassis forward and remove it from the
case.
10. Install the RXOl /RX02 assembly by reversing
steps 1 through 9.

CONF IGVRATION

CONTROLLER

POWER CABLE

Figure 2-3 Controller Board Connections

MECHANICAL SERVICING

2.3 CONTROLLER BOARD
Perform the following procedure to remove and install
the controller board. Refer to Figure 2-3.
1. Perform steps 1 through 5 in Paragraph 2.2.1 (rackmount) or steps 1 through 6 in Paragraph 2.2.2
(case-mount).
2. Remove the three screws securing the controller to
the chassis. Note the position of any nylon washer.
Swing the board upright.
3. Remove J l , J 2 , and either J4 (RXOI) or 53 (RX02)
from the controller board.
4. Remove the three nuts (not the screws) securing the
controller board to the hinge assembly. Remove the
board.
5. If the controller is an RX02, make the proper
switch settings on the new controller board (Figure
2-3). Refer to Table 2-1.

NOTE
When replacing the controller board, transfer
the nuts and washers to the new board to act as
spacers between the hinge and board.

6. Install the controller board and the RXOl/RXO2
assembly by reversing steps 1 through 5.

Table 2-1 Switch Configuration for M7744
System
Designation

RXOl
S1-1

DMA
SI-2

Function

Rx211,
RXv2 1

Off

RX02 operates as RX02
(PDP-11 , LSI-ll), DMA.

RX8E,
Rxll.
RXVl 1

Off

RX02 operates as RXOl
(PDP-8, PDP-1 1 , LSI-1 l),
programmed I/O.

RX28

Off

RX02 operates as RX02
(PDP-8), programmed I/O.

MECHANICAL SERVICING

2.4 READ/WRITE BOARD
Perform the following procedure to remove and install
the read/write board. Refer to Figures 2-4 and 2-5.

NOTE
When replacing a read/write board, check the
etch for burn or discoloration. This may be
most visible around the four transistors in both
rear corners of the board. Replace the drive as
well as the board if this occurs.
1. Perform steps 1 and 2 in Paragraph 2.3.
2. Remove all connectors for both drives (Figure 2-4
or 2-5).
3. Remove the eight screws and washers securing the

read/write board to the chassis. (Note the position
of the nylon washer if applicable.)

COLOR CODE
P7 BLUE. GREEN. BLACK. GRAY (HOME PHOTOSENSOR1
P6. BLACK. WHITE, BLUE. GRAY (INDEX PHOTOSENSOR)
P5 GRAY, BLUE (HEAD LOAD SDLENOIDI
P 4 . YELLOW, RED. GRAY, BROWN. BLACK (STEPPER MOTOR1
U..15%

Figure 2-4 RXOl Read/Write Board Connections

MECHANICAL SERVICING

P3
POWER BOARD
CONNECTOR J2

READ WRITE
BOARD
CONNECTOR J1

DRIVE HEAD
CONNECTORS

COLOR CODE
P7 - G R E Y . BLACK. GREEN. BLUE (HOME PHOTOSENSOR1
P6 - GREY, BLACK, GREEN, BLUE (INDEX PHOTOSENSOR)
P5. GREY, BLUE (HEAD LOAD SOLENOID)
P 4 . RED. YELLOW, BROWN, ORANGE, BLACK (STEPPER MOTOR)
Y.4mW

Figure 2-5

RX02 Read/Write Board Connections

CAUTION
When you reinstall the board, make sure the
screw and the nylon washer that insulates the
screw from the circuitry are in the correct location.
4. Install the read/write board and the RXOl/RX02

assembly by reversing steps 1 through 3. Connect
the power supply and drive connectors as shown in
Figure 2-4 (RXOl) or Figure 2-5 (RX02).

NOTE
Connector P3 can be reversed, but the positioning of the connector on the board is important.

MECHANICAL SERVICING

2.5 DRIVE
Perform the following procedure to remove and install
the drive.
1. Perform steps 1 and 2 in Paragraph 2.3.

2. Unplug all drive connectors from the read/write
board of the drive in question.

3. Remove the head cable from the head cable clamp.
NOTE
The following two steps apply only to the casemounted RXOlIRX02.
4. Swing the controller board down. Secure it with one

of the screws removed in step 1.
5. Set the RXOl/RX02 on its side.
6. If necessary, remove the screws securing the plenum/fan assembly to the rear of the RXOl/RXO2
(Figure 2-6).
NOTE
Some early rack-mounted RXOls do not have a
plenum/fan assembly. Retrofit any units found
this way.
7. Disconnect the drive power connector from the rear
of the drive (Figure 2-7).
CAUTION
Close the drive door before attempting to remove the drive unit. Support the drive assembly
during the next step. It can fall out of the
chassis a t this point.

8. Remove the screw holding the controller board. Remove the six drive screws securing the drive assembly to the chassis (three on each side) (Figure 2-7).
Remove the drive unit.
9. Install the drive and RXOl/RX02 assembly by reversing steps 1 through 8.
NOTE
If using the M7727 read/write board, install
the resistor assembly in head plug P3 (Figure

1-3).

MECHANICAL SERVICING

INSERT USED FOR

OLD STYLE 00-135034l4)

NEW STYLE I70.15622.Wl
&
,
'
.
M

Figure 2-6

Plenum/Fan Assembly

MECHANICAL SERVICING

DRIVE
REMOVAL
SCREWS

D R I V E A N D POWER SUPPLY R E M O V A L SCREWS

POWER
PLUGS
D R I V E POWER PLUGS (REAR VIEW; F A N R E M O V E D )
MA l a l l l

Figure 2-7

Drive and Power Supply Removal

MECHANICAL SERVICING

2.6 POWER SUPPLY
Perform the following procedure to remove and install
the power supply. Refer to Figure 2-8 and 2-9.
1. Perform steps 1 and 2 in Paragraph 2.3.

WARNING
Before attempting to remove the power supply,
disconnect power from the drive. Then short
out the two terminals on capacitors C1 and C2
(Figure 2-9).
2. Remove the jumper/harness plug from the rear of
the power supply (Figure 2-8).

3. Remove the power board connectors from 52 on the
read/write board and 53/34 on the controller board
(Figures 2-3 and 2-4).
4. Remove the interface cable clamp if applicable

(Figure 2-8).

5. Remove the three power supply screws and washers
securing the power supply to the RXOl/RX02
chassis (Figure 2-7).

6. Lift the power supply free from the chassis.
7. Install the power supply and the RXOl/RX02 assembly by reversing steps 1 through 6.

POWER

POWER SUPPLY
JUMPERiHARNESS

INTERFACE
CABLE CLAMP

Figure 2-8 Power Supply Components

MECHANICAL SERVICING

Figure 2-9 Capacitor C1 and C2 Connections

2.7 POWER BOARD ASSEMBLY (REGULATORS)
Perform the following procedure to remove and install
the power board assembly. Refer to Figures 2-8 and 2-9.
1. Perform steps 1 and 2 in Paragraph 2.3.

WARNING
Before attempting to remove the power supply,
disconnect power from the drive. Then short
out the two terminals on capacitors C1 and C2
(Figure 2-9).
2. Disconnect the connector from the center of the
power supply board (Figure 2-8).
3. Remove the power board connectors from 52 on the
readlwrite board and 53/34 on the the controller
board (Figures 2-3 and 2-4).
4. Note the polarity of the leads on capacitors C1 and
C2, and then remove the leads (Figure 2-8).
5. Remove the six screws securing the board to the
power supply and remove the board. When installing, be careful not to tighten the screws too much.

MECHANICAL SERVICING

CAUTION
Observe the correct polarity when connecting
the wires to C1 and CZ (Figure 2-9).
6. Install the power board assembly and the
RXOl /RX02 assembly by reversing steps 1 through
5.

2.8 DRIVE BELT AND AC MOTOR PULLEY
Perform the following procedure to remove and install
the drive belt and ac motor pulley.
1. Perform steps 1 and 2 in Paragraph 2.2.1 (rackmount) or steps 1 through 10 in Paragraph 2.2.2
(case-mount).
2. Set the RXOl/RXOZ on its side (case-mount only).
Remove the screws securing the bottom cover of the
appropriate drive assembly. Remove the cover.
3. While turning the spindle pulley, remove the belt
by rolling it off the spindle pulley (Figure 2-10).

DRIVE

MOTOR

PULLEY

BELT

DRIVE
SPINDLE
PULLEY

Figure 2-10 Drive Belt and AC Motor Pulley

MECHANICAL SERVICING

NOTE
If the belt has fallen off, replace the ac motor
pulley. If the belt is simply worn, go to step 6.
Replace the defective belt and pulley with the
proper parts. See Appendix A for the correct
part numbers.
4. Using a I / 16-inch Allen wrench, loosen the 6-32 set
screw securing the pulley to the motor. Remove the
pulley.

5. Place the new flanged pulley on the shaft.
6. Clean the face of the pulleys with alcohol.
7. Adjust pulley position and belt tension according to
Paragraph 3.2.
8. Install the RXOl /RX02 assembly by reversing
steps 1 through 3.

2.9 DOORHANDLE
Perform the following procedures to remove and install
the door handle.

2.9.1

Door Handle Removal

1. Remove the drive assembly according to Paragraph
2.5.
2. Remove the two mounting screws securing the
handle to the hinged cover (Figure 2-1 1). Hold the
cover securely to prevent it from suddenly springing
UP.

3. Remove the handle by pulling it through the opening in the front panel.

2.9.2 Door Handle Installation
1. Insert the handle through the front panel and install
the mounting screws, (Figure 2-1 1). Do not tighten

the screws completely.
2. Adjust the handle so that the handle brackets do
not rub on the front panel. Latch the handle.
3. Tighten the mounting screws.
4. Check the head gap clearance according to Paragraph 3.3. Do the adjustment if necessary.
5. Check again for freedom of movement. Install the
drive according to Paragraph 2.5. Begin with step 9.

MECHANICAL SERVICING

PANEL

Figure 2-1 1

Door Handle Assembly

2.10 READ/WRITE HEAD
Perform the following procedure to clean the read/write
head.

NOTE
Clean the read/write bead only when error
symptoms occur.

To reach the read/write head, remove the drive
(Paragraph 2.5) or the read/write board (Paragraph
2.4).
Lift the pressure pad assembly (Figure 2-12). Clean
the head with magnetic head-cleaner.
Install the unit by reversing step 1.

2.11 STEPPER MOTOR LEAD SHAFT
Perform the following procedure to clean the head shaft.

NOTE
Clean the head shaft only when error symptoms
occur.
1. Remove the drive according to Paragraph 2.5.

MECHANICAL SERVICING
STEPPER MOTOR
LEAD SHAFT
I

PRESSURE
PAD BAIL
P R ~ S S U R EPAD
ADJUSTMENT SCREW

CARRIAGE
ASSEMBLY

READAHRITE
HEAD

Figure 2-1 2 Head Carriage Components
(Top View)

2. Clean the shaft (Figure 2-12) with alcohol while
moving the carriage assembly in and out by handturning the shaft.
3. Add a little grease to the shaft. Use only molybium
grease (lithium base, grade #2).
4. Install the drive according to Paragraph 2.5. Begin
with step 9.

ALIGNMENT AND
ADJUSTMENT

3.1 HANDLE LATCH WIRE
Adjust the handle latch wire (Figure 2-11) so that it
firmly holds the handle latch. The wire must not rub
against the latch when the handle is pushed past the
latched position. To adjust the handle latch wire properly, perform the following steps.

1. Pull the latch wire out by placing a screwdriver between the wire and the front panel. Pry one side at a
time until the wire firmly holds the handle latch.
2. Pull the latch wire in by tapping the wire loop on
one side at a time. Do this until it does not rub the
handle latch when the handle is pushed past the
latched position.

3.2 DRIVE BELT AND AC MOTOR PULLEY
Perform the following procedure to adjust the drive belt
and ac motor pulley.
1. Remove the drive belt and a c motor pulley accord-

ing to Paragraph 2.8.

2. Using a straight edge, make sure the motor pulley
aligns with the spindle pulley (Figure 3-1).

n
I

"NO
GAP

DRIVE PULLEY

n I-.
! !

STRAIGHT
EDGE

NO
GAP

MOTOR PULLEY
CORRECT ADJUSTMENT

n
I
I

1
1

DRIVE PULLEY

STRAIGHT
EDGE
GAP
I 1
MOTOR PULLEY

INCORRECT ADJUSTMENT
(MOTOR PULLEY TOO HIGH, SHOULD BE LOWERED1

Figure 3-1

.?:%

Motor Pulley Alignment
41

ALIGNMENT AND ADJUSTMENT

CAUTION
Misadjustment of the drive pulley causes the
belt to fly off the pulley.

3. Tighten the set screw on the flat of the motor shaft.
4. Use the spacer gauge to check for correct spacing
between the pulleys. This is critical for proper belt
tension. When the motor and spindle pulleys hold
the spacer gauge in place, the spacing is correct
(Figure 3-2).

NOTE
Each type of drive has a different spacer gauge.
Use the correct gauge (Appendix A).
5. If the spacing is wrong, loosen the four motormounting screws (Figure 3-2). Adjust the position
of the motor for correct spacing and tighten the
four screws.
4 MOTOR
MOUNT I NG
SCREWS

Figure 3-2

DRlVE MOTOR
BELT

Underside View of Drive

DRIVE SPINDLE
PULLEY

ALIGNMENT AND ADJUSTMENT

6. Install the belt by rolling it onto the large spindle
pulley.

CAUTION
Do not stretch the belt onto the pulley. It is nylon, not rubber. Stretching breaks nylon fibers
and damages the belt.
7. Return to Paragraph 2.8.

3.3 HEADGAP
Perform the following procedure to adjust the head gap.
1. Remove the read/write board according to Paragraph 2.4.

NOTE
Make sure the carriage assembly is riding on
the top surface of the pressure pad bail (Figures 3-3 and 3-4).

STEPPER MOTOR
LEAD SHAFT
ITURN TO MOVE HEAD1

TRACK 1

TRAC

CAR~IAGE

ASSEMBLY
READWRITE
HEAD

Figure 3-3 Head Gap Adjustment

ALIGNMENT AND ADJUSTMENT
1kDJUSTMENT SCREW

LOCKING NUT
(NOT ON ALL UODELSI

J
l

at------

SQLENOID

”$.

. O W GAP

READWRITE HEAD

-1u.u

Figure 3-4 RXOl Pressure Pad Mechanism

(Front View)

2. With the drive door closed, move the read/write
head and carriage assembly as far away from the
spindle as possible (track 1) (Figure 3-3).

NOTE
Move the bead and carriage assembly by turning the stepper motor shaft.
3. With the drive door still closed, lift the pressure pad
and place the plastic shim between the read/write
head and felt pressure pad.

NOTE
The size of the plastic shim (P/N 934612301) used for step 3 is important. Cut the yellow
(0.020 in) shim to a 1 inch x 1 inch square.
4. Refer to Figures 3-4 and 3-5. Set the RXOl/RXOZ

on its side. If the shim stays in place, the head gap
is too small. Unscrew the pressure pad adjustment
screw until the shim falls out of place but drags
slightly. If the shim does not drag, the head gap is
too wide. Tighten the screw so that the shim drags
as it falls out. On some models the gap is tightened
by the locknut.

ALIGNMENT AND ADJUSTMENT

ADJUSTMENT
SCREW

,020”GAP
READ W R I T E HEAD
U..s€a,*

Figure 3-5 RX02 Pressure Pad Mechanism
(Front View)
5 . Once the gap has been adjusted, open and close the
door several times.

6. Close the door and recheck the gap. If it has
changed, readjust the gap starting at step 2.
7. Move the carriage assembly as close to the spindle
as possible (track 76) and check the gap. Then,
move the assembly to a midpoint, and check the
gap. If the gap is correct at both points, skip step 8.
8. Refer to Figure 3-5. If there is a pressure pad bail
screw, loosen it. Move the bail so it is parallel to the
carriage and the gap is the same at all tracks. Tighten the screw and perform step 6 again.

NOTE
If there is no pressure pad bail screw, adjustment is not possible. Replace the drive (Paragraph 2.5).
9. Replace the read/write board according to Paragraph 2.4.

APPENDIX A
SPARE PARTS LIST
~

Part

~~~

Description

DEC P/N

Power supply

110 V 60 Hz
llOV50Hz
230 V 50 Hz

H771-A
H771-C
H771-D

Power harness

Power supply to drive
90-120 V 50/60HZ
100-132 V 50 HZ
180-240 V 50 HZ
200-264 V 50/60 HZ

70-10696-02
70-10696-01
70-10696-04
70-10696-03

Fuse

2A slo blow

90-072 16

Power board
assembly

Regulator

70-107 18-00

Plenudfan
assembly
(Figure 2-6)

1 15 V, dual, new style 70-15622-04
230 V, dual, new style 70-15622-05
115 V, dual, old style 70-13503-04
230 V, dual, old style 70-13503-05

Fan

115 V, new style
230 V, new style
115 V, old style
230 V, old style

12-15 113-00
12-15742-00
12-13 185-00
12-10930-01

Drive

60 Hz
50 Hz

70-1 3077-00
70-13077-01

Flanged ac
motor pulley

60 Hz
50 Hz

74-2 1078-00
74-21 078-01

Interface cable

Controller to host

BC05L8
BC05L15

All Drives

(Figure 2-6)

APPENDIX

Part

Description

DEC P/N

Interfacehoard

Case-mounted units
only

BC08R-02
54-14168

Sems screw

Hold-down for
90-09984-02
controller
(Lockwasher attached)

All Drives

RXOl Drives Only
Controller board

M7126

Readwrite board

M7721

Resistor assembly Must be installed in
P3 connector when
using M7127

10-16263-00

DIP cable

70-08612-OF

M1126 to MI721

Door handle
assembly

70- 14291-00

RX02 Drives Only
~~

Controller board

M1144

Readwrite board

M1745

Ribbon cable

M7744 to M7145

Door handle
assembly

70-15580-00
70-13454-00

70 Class Drives Only (70-13077)
Drive belt
Spacer gauge

60 Hz

50 Hz

12-14005-00
12-14005-01

60 Hz
50 Hz

93-06353-02
93-06353-03

APPENDIX

Part

Description

DEC P/N

Calcomp" Drives Only (RXOl-CNCC)*
Drive belt

60 Hz
50 H z

12-13454-00
12-13454-00

Spacer gauge

60 H z
50 H z

93-06353-00
93-06353-01

" CalComp is a trade name of California Computer Products, Inc.

These drives should be used when locally available to replace
identical units. They cannot be ordered Only 70 class drives CM be
ordered.

READER’S C O M M E N T S
RXOI/RX02 POCKET SERVICE GUIDE
EK-RXO12-PS-002
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