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EK-0TU78-UG-2

December 1981

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Document:	TU78 Magnetic Tape Transport User's Guide
Order Number:	EK-0TU78-UG
Revision:	2
Pages:	65
Original Filename:

OCR Text

EK-OTU78-UG-002

TU78 Magnetic
'. Tape Transport ..
User's Guide

·momoomo

EK-OTU78-UG-002

TU78 Magnetic Tape Transport
User's Guide

digital equipment corporation • maynard, massachusetts

1st Edition, December 1980
2nd Edition, May 1981

Copyright © 1980, 1981 by Digital Equipment Corporation
All Rights Reserved
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

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

MASSBUS
OMNIBUS
OS/8
RSTS
RSX

lAS

CONTENTS

CHAPTER 1
1.1
1.2
1.3
1.4
1.5

GENERAL DESCRIPTION
Introduction ......................................................... 1-1
Physical Description ................................................... 1-2,
Functional Description ..........................' ....................... 1-7
Applicable Documents ................................................ 1-10
Mechanical and Electrical Specifications .................................. 1-10

CHAPTER 2 OPERATION
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
2.2.9
CHAPTER 3
3.1
3.1.1
3.1.2
3.1.3
3.2
3.2.1
3.2.2
3.3
3.3.1
3.3.2
3.4
3.4.1
3.4.2
3.5
3.5.1
3.5.1.1
3.5.1.2
3.5.1.3
3.5.1.4

Controls and Indicators ................................................ 2-1
Operating Procedures .................................................. 2-3
Power ............................................................ 2-3
Autoload/Manual Load Selection ....................................... 2-3
Autoload ......................................................... 2-4
Manual Load ........................................................ 2-4
Probable Causes of Load Failure ....................................... 2-7
Midreel Load ...................................................... 2-8,
Unload ........................................................... 2-8
Rewind ........................................................... 2-8
On-Line/Off-Line ................................................... 2-8
INSTALLATION
Site Planning ........................................................ 3-1
Space Requirements .. '............................................... 3-1
Power Requirements ................................................ 3-1
Environmental Requirements .......................................... 3-2
Unpacking and Inspection .............................................. 3-2
Unpacking ........................................................ 3-2
Inspection ........................................................ 3-3
Single Transport Installation ............................................ 3-4
Mechanical Installation ............................................... 3-4
Power and Cabling .................................................. 3-7
Multiple Transport Installation .......................................... 3-11
Mechanical Installation .............................................. 3-11
Power and Cabling ................................................. 3-15
Acceptance Testing .................................................. 3-1 7
Turn-On and Loading Checkout ....................................... 3-18
Power-On ...................................................... 3-18
Load Sequence Without Tape ....................................... 3-18
Inhibited Autoload Sequence ....................................... 3-20
Autoload Sequence .............................................. 3-20

iii

3.5.1.5
3.5.1.6
3.5.1.7
3.5.1.8
3.5.2
3.5.3
3.5.3.1
3.5.3.2

Manual Load Sequence ............................................ 3-22
Unload Sequence ................................................ 3-22
Manual Load Repeatability ........................................ 3-22
Autoload Repeatability ........................................... 3-24
Subsystem Quick Check ............................................. 3-24
TM78/TU78 System Level Diagnostics .................................. 3-25
DECsystem 10/20 Diagnostics ......."............................... 3-26
VAX-l 1/780 Diagnostics .......................................... 3-26

CHAPTER 4 CUSTOMER CARE AND PREVENTIVE MAINTENANCE
4.1
4.2
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.4
APPENDIX A

Customer Responsibilities .............................................. 4-1
Magnetic Tape Care ................................................... 4-1
Preventive Maintenance ................................................ 4-2
General ........................................................... 4-2
Preventive Maintenance .............................................. 4-2
Magnetic Tape Transport Cleaning Kit ................................... 4-2
TU78 Tape Transport ................................................ 4-3
Ordering Supplies, Accessories and Documentation ........................... 4-5
GLOSSARY

FIGURES
I-I
1-2
1-3
1-4
1-5
1-6
1-7
2-1
2-2
2-3
2-4
2-5
2-6
3-1
3-2
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

Basic System Configuration ............................................. 1-1
TU78 Master Tape Transport ............................................ 1-2
Base Assembly ....................................................... 1-4
Card Cage Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Power Pack Assembly (Rear View) ........................................ 1-6
Possible TU78 Configurations ........................................... 1-7
Master TU78 Functional Block Diagram ................................... 1-8
TU78 Control Panel ................................................... 2-1
Autoload/Manual Load Selection ......................................... 2-3
Tape Content Limit ................................................... 2-3
Autoload Sequence with Operator Troubleshooting ........................... 2-5
Tape Path and Controls ................................................ 2-6
Manual Load Sequence with Operator Troubleshooting ........................ 2-7
Space and Service Clearance (Top View) ................................... 3-1
Unpacking the TU78 .................................................. 3-3
TU78 Mounting for Shipment ........................................... 3-4
Location of Stabilizer Arm and Leveler Feet ................................ 3-5
PCB Shipping Bracket (Side View) ........................................ 3-6
TU78 Power Distribution ............................................... 3-7
874-E Power Controller ................................................ 3-8
Rear of Power Pack with Pulley Cover Removed ............................. 3-9
Cabinet Placement for Maintenance Display Visibility ........................ 3-11
Top Cover Fastener .................................................. 3-13
Cabinet with Side Panels and Top Cover Removed ........................... 3-13
TU Bus Cable Routing for a Multiple Transport Configuration ................. 3-14
Radial TU Bus Connections ............................................ 3-16
Cable Orientation on TU78 MIA PCBA (Slave Only) ......................... 3-17
TM78 Maintenance Keypad ............................................ 3-19

3-16
3-17
3-18
3-19
3-20
4-1

Load Sequence Without Tape ........................................... 3-19
Inhibited Autoload Sequence ........................................... 3-20
Autoload Sequence .................................................. 3-21
Manual Load Sequence ................................................ 3-22
Unload Sequence .................................................... 3-23
Transport Items for Daily Cleaning ....................................... 4-4

TABLES
1-1
1-2
2-1
2-2
3-1
3-2
3-3
3-4

Related Documents ...... ~ ........................................... 1-11
Mechanical and Electrical Specifications .................................. 1-11
TU78 Controls ....................................................... 2-1
TU78 Indicators ...................................................... 2-2
Primary Power Connections ............................................. 3-9
Pulley/Belt Part Numbers for Altitude Changes ............................. 3-10
TM78/TU78 Diagnostics for Acceptance Testing ............................ 3-25
Maximum Error Rate Per Pass .......................................... 3-27

CHAPTER 1
GENERAL DESCRIPTION

1.1 INTRODUCTION
The TU78 magnetic tape transport writes and reads data in 9-track phase-encoded (PE) or group code
recording (GCR) format. Bit density is 1600 bits per inch (bits/in) for the PE format and 6250 bits/in
for the GCR format. The transport can read data in the forward or reverse direction. The read/write
tape speed for both directions is 125 inches per second (in/s). Nominal rewind time for a 731.5 m (2400
ft) reel is 65 seconds.

The TU78 interfaces with the system processor via the MASSBUS, a MASSBUS controller, and a
TM78 tape formatter. Up to four TU78s may be driven by a single TM78 formatter. Figure 1-1 illustrates the basic TU78 system configuration. The TM78 tape formatter and its power supply (H7422AB) are housed in the TU78 cabinet, an H9500 corporate cabinet. (The specific model of the H9500
cabinet series used for the TU78 is H9602-KA. However, this manual refers to the cabinet as the
H9500.) The TU78s containing a TM78 are called master units; TU78s without the TM78 are called
slave units. Both master and slave units contain an 874-E power controller. Earlier TV78 models contain an 872-E power controller. The two types are electrically identical, but differ slightly in the
location of remote control jacks.

*1. DECSYSTEM 20 (KL 10 & RH20)
2. PDP-11/780VAX&RH780

L ___ _
TO 1-3
OTHER TU78
TRANSPORTS

Figure 1-1

Basic System Configuration

1-1

TU78
BASE ASSEMBLY

TM78 TAPE
FORMATTER

CONTROL

MA-6155A

a. Front View
Figure 1-2

TU78 Master Tape Transport (Sheet 1 of 2)

1.2 PHYSICAL DESCRIPTION
Figure 1-2 illustrates the locations of the major subassemblies of the TU78. They are listed below.
TM78 tape formatter (master TU78 only)
H7422-AB power supply (master TU78 only)
874-E power controller
TU78 transport (base assembly, card cage area, and
power pack assembly)

1-2

EXHAUST
FANS (2)
BLOWER
FAN

o
H7422 - AB
POWER SUPPLY

HEAT
EXCHANGER

PULLEY
COVER
BLOWER
MUFFLER

MA-7013

h. Rear View
Figure 1-2

TU78 Master Tape Transport (Sheet 2 of 2)

Figure 1-3 identifies the components of the base assembly. They are listed below.
Control assembly (PN 29-23771)
Reel sense assembly (PN 29-23216)
Backwrap defeat switch (PN 29-23297)
Reel hub assembly (PN 29-23475)
Buffer box door assembly (PN 29-23215)
Tape in path (TIP) assembly (PN 29-23243)
EOT IBOT assembly (PN 29-23242)
Head (PN 29-23767)
Cartridge interlock switch (PN 29-16280)
Upper restraint (PN 29-23225)

1-3

CARTRIDGE

REEL HUB ASSEMBLY

REEL SENSE
ASSEMBLY

EDT/BOT ASSEMBLY

HEAD

MA-2636A

a. Front View
Figure 1-3

Base Assembly (Sheet 1 of 2)

Lower restraint (PN 29-23224)
Cartridge motor (PN 29-23280)
Pressure switch (pneumatic interlock) (PN 29-23239)
Pressure valve assembly (PN 29-23249)
Interconnect Fl printed circuit board (PCB) (PN 29-23770)
Reel motor assemblies (2) (PN 29-23236)
Write protect assembly (PN 29-23235)
Vacuum valve assembly (PN 29-23248)
Pressure switches (vacuum) (2) (PN 29-23238, 29-23239)
Pack sense assembly (PN 29-23217)
Capstan motor assembly (PN 29-23768)
Service lock
Preamp PCB (PN 29-23766)
Vacuum transducer assembly (PN 29-23246)
Pressure switch (column limit) (4) (PN 29-23238)
Figure 1-4 illustrates the card cage area containing the following items.
Multiple interface adapter (MIA) PCB (PN 29-23769)
Read PCB (PN 29-23762)
Write PCB (PN 29-23763)
Control M2 PCB (PN 29-23764)

1-4

PRESSURE SWITCH
(PNEUMATIC INTERLOCK)

PRESSURE VALVE
ASSEMBLY

INTERCONNECT Fl
PCB

PRESSURE
SWITCH
(COLUMN LIMIT)

CARTRIDGE
MOTOR

PRESSURE SWITCH (2)
(VACUUM)

r-t~~~~~~~~~. VACUUM VALVE

ASSEMBLY

SERVICE
LOCK

CAPSTAN MOTOR
ASSEMBLY

PACK SENSE ASSEMBLY
(NOT SHOWN)

REEL MOTOR ASSEMBLY
(TAKE UP REEL)
MA·2664

b. Rear View
Figure 1-3

Base Assembly (Sheet 2 of 2)

Capstan/regulator PCB (PN 29-23765)
Reel servo PCB (PN 29-23231)
Exhaust fans (2) (PN 12-17916-02)
Interconnect Dl PCB (not shown in Figure 1-4) (PN 29-23211)
Figure 1-5 illustrates the power pack assembly containing the following items.
Rectifiers (3) (PN 29-23311,29-23312)
Vacuum hose
Fuse panel
Air filter (PN 29-23259)
Blower (below serial number SP002386-PN 29-23298)
Blower (serial number SP002386 and above-PN 29-24013)
Pulley cover
Power transformer terminal strip
Compressor (PN 29-23257)
Motor (PN 29-23287)
Transformer (PN 29-23258)
Muffler (PN 29-23220)
Heat exchanger fan (PN 29-17916-02)
1-5

EXHAUST FANS (2)

READ PCB

- WRITE PCB

CAPSTAN SERVO
PCB

REEL SERVO PCB

Figure 1-4

MA-2664A

Card Cage Area

TRANSFORMER

MOTOR

(UNDER COVER)

BLOWER

PULLEY COVER

Figure 1-5

Power Pack Assembly (Rear View)

1-6

MA-2643A

rrmDUALPORT MASTER -

TU78 - BB ( 60 Hz )
TU78- BD (50 Hz)
TM78- BB

TU78
TAPE
TRANSPORT

CPU
A

I
I

TU BUS 1

TU78 SLAVE
TU78 - AF ( 60 Hz )
TU78 - AJ ( 50 Hz )
TU78
TAPE
TRANSPORT

L _ _ _ _ _ _ _ .J
s:

:t>
~
OJ

Cf)

TU78 - AB ( 60 Hz )
TU78 - AD (50 Hz )
TU78
TAPE
TRANSPORT
0

1... _ _ _ _ _ _ _

I
I
...1

RH
0
CPU
B
RH
1

TU78
TAPE
TRANSPORT
1

MA-7014

* MASSBUS TERMINATOR (DEC PN 70 - 09938 - 00 )

Figure 1-6

TU78 SLAVE
TU78 - AF (60 Hz )
TU78 - AJ ( 50 Hz )

Possible TU78 Configurations

1.3 FUNCTIONAL DESCRIPTION
Figure 1-6 illustrates the various TU78 configurations possible from the MASSBUS. The TM78 tape
formatter interfaces with up to four TU78 transports to the MASSBUS. Additional TM78s may be
added (a maximum of eight), with each formatter interfacing up to four additional TU78s. Thus, the
maximum configuration interfacing a MASSBUS controller consists of 8 TM78 formatters and 32
TU78 transports. A TM78 may also be dual-ported so that each subsystem can be driven by two host
CPUs.
The TM78 tape formatter is housed in the TU78 cabinet. Those cabinets containing a TM78 (and its
H7422-AB power supply) are called master transports. Those cabinets without the TM78 and H7422·
AB are called slave transports. The TU78 master transport is identical to the TU78 slave transport.
Figure 1-7 is a functional block diagram of a TU78 master tape transport. During a write operation the
TM78 accepts write data from the MASSBUS and formats it into 8-bit data characters for the TU78
transport. MASSBUS data is in the following formats: PDP-IO compatible, PDP-IO core dump, PDP·
10 high-density compatible, PDP-IO high density dump, PDP-IO/II/15 image, PDP-II normal or
PDP-iS normal. The TM78 disassembles Massbus data under control of the CPU which specifies the
data format. During a read operation, 8-bit characters received from the transport are formatted into.
data words and placed on the MASSBUS. The TM78 assembles the data characters into the MASSBUS format specified by the CPU. The TM78 writes and reads data in either 1600 bits/in PE or 62S0
bits/in GCR formats.

1-7

FROM CPU

r;;:;:;S~T-

REMOTE
SWITCHING
CONTROL BUS
(POWER ON/OFF)

----l

-- - - -- -- - -- - - - - - - ------ -- -- -

INPUT POWER

SUPPLY SERVO FEEDBACK

AUTOLOAD
, - - - - - - - , MOTION
COMMANDS

±5V
±15V
DC LO
AC LO
FAN
MIA

......
I
00

PCB
WRITE DATA
READ DATA
CONTROL COMMANDS
STATUS SIGNALS

CONTROL
LOGIC &
MANUAL
CONTROLS~~~~~~~~
AUTOLOAD
L -_ _ _ _ _~

MOTION
COMMANDS

TM78
TAPE
FORMATTER

SUPPLY LOOP
PNEUMATIC
COLUMN
(BUFFER BOX)

MOTION
COMMANDS
TACHOMETER OUTPUT

CAPSTAN
TACHOMETER

MOTOR

PNEUMATIC COLUMN
(BUFFER BOX)

VACUUM
SENSE
~----

PRESSURE
SENSE

• MASTER TU78 ONLY
• "·TAKE UP PRESSURE TRANSDUCER

Figure 1-7

TO TRANSPORT (N)

Master TU78 Functional Block Diagram

AC LINE

FROM COMPRESSOR

__ J

puring a write operation, the TM78 assembles 8-bit tape characters and sends them to the TU78 over
the TU bus. Error detection is accomplished by parity checks (PE and GCR modes), and (GCR mode
only) by cyclic redundancy checks (CRC) and auxiliary cyclic redundancy checks (ACRC). Error detection occurs for both read and write operations. During a write operation, a read-after-write function
is performed: the TM78 reads data j~st written and performs error checking. During a read operation
the TM78 can perform automatic error correction. Single-track errors can be corrected in PE; and using a special error correction character (ECC) double-track errors can be corrected in GCR.
The TM78 also controls and monitors tape transport operation. It receives operational commands from
the host CPU, selects the desired transport, and issues functional (data transfer) and motion (non-data
transfer) commands. It monitors transport operation and provides error and status information to the
host CPU.
The H7422 power supply provides regulated ± 5 V and ± 15 Vdc operating voltage for the TM78.
Power fail signals AC LO and DC LO are also supplied to the TM78.
The 874-E power control supplies ac power to the transport cabinet. It provides filtering for the ac input
power supplied to switched outlets when the remote power on/ off line is enabled from the host CPU via
the remote switching control bus. There is no power on/off control on the TU78 control panel, transport
power is controlled by the host CPU. The switched ac is supplied to the H7422 power supply and TM78
cooling fan (master TU78 only), the transport power pack, the three cabinet cooling fans, and the compressor heat exchanger.
The basic TU78 transport contains the following seven functional areas (Figure 1-7).
Capstan servo subsystem
Reel servo subsystem (2)
Pneumatic subsystem
Read/write subsystem
Control logic and manual controls
MIA interface
Power supply and distribution
The capstan servo subsystem controls the speed and direction of tape movement past the read/write
heads. The subsystem is a velocity servo that receives command signals from the control logic specifying forward, reverse, or rewind motion. The capstan motor responds with the appropriate velocity.
The capstan tachometer generates a feedback signal proportional to speed. This signal is summed with
the basic command signal in order to maintain the correct capstan velocity at all times.
The reel servo subsystems control the speed of the tape reels in order to maintain optimum tape tension
between the supply and take-up reels. The supply reel and take-up reel servos are similar but separate
subsystems. The path followed by the tape (in either direction) between the supply and take-up reels
contains two tape loops in the buffer box (supply loop and take-up loop). The separately formed loops
are maintained by a vacuum in conjunction with automatically controlled reel motor speeds. In effect~
the reel servos function to feed tape into and remove tape from the buffer box at the rate required to
maintain the correct loops.
Signals developed within the pneumatic subsystem initiate servo operation. The subsystem senses that
the tape loop position has changed as a result of forward or reverse tape motion. Air is drawn from the
closed ends of the two buffer boxes creating a vacuum and causing the tape loop to form in each box.
The differential between the positive pressure inside the loop and the relatively negative pressure at the
closed end of the buffer box (outside the loop) maintains the proper tension on the tape during the tapeloaded state.

1-9

There is a separate chamber behind each buffer box, connected to the box by a series of holes. The
spacing and arrangement of these holes is such that, if the loop becomes larger, more holes are exposed
to the positive (atmospheric) pressure inside the loop, and fewer to the lower pressure (vacuum) area
outside the loop. This causes pressure in the chamber to rise. Conversely, if the loop becomes smaller,
the pressure in the chamber decreases.
Pressure transducers are connected to the supply and take-up chambers. They interpret pressure variations in order to provide the supply and take-up servo feedback signals. The pressure sensitive signals
feed back to the reel servos to adjust the velocity of the reel motors for the proper loop in the two buffer
boxes. The uppermost and lowermost holes in each buffer column are limit ports. These connect to .
supply and take-up limit switches which feed back to both the supply and take-up servos. If the tape
crosses a limit port in either the supply or take-up columns, a disabling signal couples back to the servos, stopping both reel motors before tape damage occurs.
A pneumatic interlock shuts down the capstan servo and reel servos if a pneumatic failure is detected.
The pneumatic subsystem contains a blower which creates the vacuum for the tape columns, and a
compressor which generates pressure for the tape path bearings. Sensing devices monitor vacuum and
pressure. If either is lost, the sensing device sends a VAC/PRES signal to the three servo subsystems,
stopping the servo motors before tape damage occurs.
The read/write subsystem processes data and transfers it to and from the magnetic tape. The read function processes data picked up from the tape by the read heads. It translates information from the recorded PE or GCR format to digital data acceptable to the external controlling circuits. The function
includes the read-after-write capability that permits the formatter to verify execution of write command while writing is in progress. The write function prepares incoming data for recording in PE or
GCR format and writes the information on the tape in the selected format. The read/write subsystem
also develops amplitude track in error (AMTIE) status signals. It sends nine AMTIE signals to the
formatter, one for each track, which become active when the strength of the analog signal read from
tape falls below a specified threshold. During a write function this causes the operation to be retried.
During a read function, AMTIE signals assist the formatter in developing pointers for the error correction process.
The control logic and manual control circuit interfaces other TU78 subsystems. The control logic transfers read/write data to and from the read/write subsystem. It also transfers the operational commands
to the capstan servo. During the autoload sequence, logic circuits control the sequence steps by issuing
appropriate commands to the reel servos. The control logic monitors and controls timing of the autoload
sequence steps and other operational sequences, such as rewind. It processes commands generated by
the manual controls and applies them to the appropriate subsystem. Control logic also senses transport
status (e.g., transport selected, on-line, EaT, BOT, etc.), and modifies signals to the read/write and
servo subsystems. Logic lights the appropriate control panel indicators to indicate transport status.
Transport status is sent to the TM78 formatter via the MIA interface module.
The MIA module couples control/status, read/write, and AMTIE signals from the tape unit bus (TU
bus) to the transport. The MIA adapts signals on the TU bus to the format required by the transport,
and vice versa. This includes multiplexing, de-multiplexing, signal gating, latching, and timing.
Power supply functions include ac rectification, filtering, dc regulation, and distribution of power to the
various subsystems.
1.4 APPLICABLE DOCUMENTS
Table 1-1 lists documents applicable to the TU78 tape transport.
1.5 MECHANICAL AND ELECTRICAL SPECIFICATIONS
Table 1-2 details the mechanical and electrical specifications of the transport.
1-10

Table 1-1

Related Documents

Title

Doc No

Contents

TM78 Magnetic Tape
Formatter User Guide

EK-OTM78-UG

Description, programming,
and installation
information

TM78 Magnetic Tape
Formatter Technical
Manual

EK-OTM78-TM

Theory of operation,
programming information,
installation, and
maintenance of the TM78
formatter and H7422 power
supply

TU78 Magnetic Tape
Transport Technical
Manual (Volume 1)

EK-1TU78-TM

Schematics and logic
prints of TU78

TU78 Magnetic Tape
Transport Technical
Manual (Volume 2)

EK-2TU78-TM

Description, installation,
operation, theory and
maintenance of TU78

TU78 Subsystem Pocket
Service Guide

EK-OTU78-PS

Summary of troubleshooting
and maintenance procedures

TU78/TM78 Magnetic
Tape Transport/
Formatter IPB

EK-OTU78-IP

Exploded views and parts
lists of TU78 and TM78

TU78 Field Maintenance
Print Set

MP01061

Engineering drawings for
TU78 mechanics and
cabinet

TM78 Field Maintenance
Print Set

MP01061

Engineering drawings and
parts lists for TM78
mechanics and logic

874 Power Controller
IPB

EK-00874-IP

Exploded views and parts
lists of 874

Table 1-2

Mechanical and Electrical Specifications

Tape (computer grade)
Width
Thickness

12.6492 mm ± 0.0508 mm (0.498 in ± 0.002
in)
0.0381 mm (1.5 mil)

Tape tension

2.780 N (10.0 oz +0.0/ -1.0 oz) nominal

Reel diameter (autoload)

266.7 mm (10.5 in) maximum (note 1) and
Easy-Load cartridge 1 and 2

Recording modes

1600 bits/in (3200 FCI) PE
6250 bits/in (9042 FCI) GCR

1-11

Table 1-2 Mechanical and Electrical Specifications (Cont)
Magnetic head

Dual stack (with erase head)

Tape speed

3.2 m/s (125 in/s)

Instantaneous speed
variation

± 3 percent

Long term speed
variation

± 1 percent (forward)
± 2 percent (reverse)

Rewind time for 731.5 m
(2400 ft) tape

65 seconds nominal (80 seconds
maximum)

Tape cleaner

Dual blade type connected to vacuum
supply

Interchannel displacement
error
Read
Read-after-write

3.81 ~m (150 ~in) maximum (note 2)
8.89 ~m (350 ~in) maximum (note 3)

Start/stop time
Start
Stop

1.1 ms ± 0.1 ms
1.3 ms ± 0.1 ms
1.1 ms ± 0.1 ms

Start distance

1.91 mm +0.25/ -0.38 mm
(0.075 in +0.010/ -0.015 in)

Stop distance

2.16 mm +0.25/ -0.38 mm
(0.85 in +0.010/ -0.015 in)

Beginning of tape (BOT) and
end of tape (EaT) detectors
(note 4)

Photoelectric

Tape creepage

None

Pneumatic interlock

Tape motion disabled when vacuum is lost
in vacuum column

Load time

No greater than 10 seconds without a
retry, and 20 seconds with a retry for
10.5 in reels

Unload time

Less than 7 seconds for 10.5 in reels

Write gap to read gap
distance

0.381 cm ± 0.013 cm (0.150 in ± 0.005 in)

Weight

286 kg (630 Ibs) (master unit)

1-12

Table 1-2 Mechanical and Electrical Specifications (Cont)
Cabinet dimensions
Height
Width
Depth (from face of
front door to rear of
cabinet)

152.4 cm (60.0 in)
67.3 cm (26.5 in)
81.9 cm (32.3 in)

Operating temperature
Nonoperating temperature

15° to 32° C (59° to 90° F) (note 5)
-46° to 71 ° C (-50° to 106° F)

Operating altitude

Om to 2134 m (0 ft to 7000 ft) (note 6)

Nonoperating altitude

9100 m (30,000 ft) maximum

Power
Volts ac
Frequency
Kilovolt amp (kVA)
Standby (loaded)
Start/stop

188 V to 264 V at 60 Hz
198 V to 264 V at 50 Hz
50 Hz ± 1 Hz or 60 Hz ± I Hz
1.5 kVA maximum (note 7)
2.4 kV A maximum (note 7)

NOTES
1.
177.8 mm (7 in) and 216.0 mm (8.5 in) reels may be used but canno.t be auto.lo.aded.
2.

The maximum displacement between any two. bits o.f a character when reading a master tape using the read
sectio.n o.f the read-after-write head.

The maximum displacement between any two. bits o.f a character o.n a tape written with all o.nes using the write
sectio.n o.f the read-after-write head.

Appro.ximate distance fro.m detectio.n area to. write head gap is 35.6 mm (1.40 in).

Fo.r data transfer, the o.perating temperature is dictated by the nature o.f the tape material.

Operatio.n abo.ve 610 m (2000 ft), in 610 m (2000 ft) increments requires installatio.n o.f high altitude pulleys
and belts in TU78 po.wer pack.

Slave unit o.nly. Add 700 W fo.r master units.

1-13

CHAPTER 2
OPERATION

2.1 CONTROLS AND INDICATORS
The TU78 operational controls and indicators are located on the transport control panel. The controls
and indicators are illustrated in Figure 2-1. The controls are described in Table 2-1, the indicators in
Table 2-2.

AUTO

../""BACKWRAP
DEFEAT

MAN

powerO

O
PORT

on line

LOAD/REW

ON LINE

bot

file protect

UNLOAD

DODD

O-A
1-B
2-A/B
3-TEST

load fault

RESET

62500
16000

TU 78
MA-2662A

Figure 2-1
Table 2-1

TU78 Control Panel

TV7S Controls

Control

Function

Port Select Switch

Selects the MASSBUS I/O port(s) allowed to send commands to this tape
transport.
Switch
Position

Function

Transport connected to MASSBUS port A
Transport connected to MASSBUS port B

Transport connected to both MASSBUS ports A and B

Transport disconnected from both MASSBUS ports and
placed in maintenance mode (available to TM78 formatter
maintenance panel)

2-1

Table 2-1

TV78 Controls (Cont)

Control

Function

LOAD/REW

Initiates one of three sequences.
1.

With no tape in path, initiates a load sequence.

With tape in path but not tensioned, initiates a midreelload sequence.
In a mid reel load sequence the tape loads and runs in reverse direction
to BOT.

With tape in path and tensioned, and the transport off-line, the tape
rewinds to BOT. If the tape is already at BOT or if the transport is online, no action occurs.

ON LINE

Switches the transport off-line or on-line.

UNLOAD

If the TU78 is off-line, causes the tape to rewind and unload. If the tape is
already at BOT, it unloads. If the TU78 is on-line, button has no dfect.

RESET

Terminates all functions and clears a load fault.

BACKWRAP
DEFEAT

AUTO (automatic) position: Allows a backwrap and retry for 10.5 inch reel,
with or without a cartridge
MAN (manual) position: Inhibits a backwrap and retry for 10.5 inch reel
without a cartridge

Table 2-2

TU78 Indicators

Indicator

Meaning

Power

Presence of dc and secondary ac power.

BOT

Tape is at BOT.

On Line

TU78 is on-line. The transport reverts to the off-line mode if any of the following occur.
1.

ON LINE button is pressed:

External rewind unload command is received.

Vacuum column interlock is broken.

AC power is lost.

RESET button is pressed.

File Protect

Tape reel without a write enable ring has been loaded onto the transport.

Load Fault

Load fault has occurred.
1.

Autoload sequence has failed to load a tape from a 267 mm (10.5 in) reel after two
tries.

Load sequence has failed to load tape from a 216 mm or 178 mm (8.5 in or 7 in)
reels.
2-2

Table 2-2

TU78 Indicators (Cont)

Indicator

Meaning

1600

Tape transport set to read or write at 1600 bits/in (PE mode).

6250

Tape transport set to read or write at 6250 bits/in (GCR mode).

2.2

OPERATING PROCEDURES

2.2.1 Power
When the system CPU is turned on, power is applied to the TU78. The CPU remotely enables the 874E power control, which in turn applies ac power to the TU78 cabinet.
2.2.2 Autoload jManual Load Selection
Figure 2-2 illustrates various conditions and interlock settings that determine the selection of an autoload or manual load procedure.
The manual loading procedure must be used for a 216 mm or 178 mm (8.5 in or 7 in) reel. If a 267 mm
(10.5 in) reel in a cartridge is used, the cartridge engages the cartridge interlock. This bypasses the
autoload interlock and makes the autoload procedure necessary.
A full reel of tape must be used for an autoload sequence. Automatic loading requires that the outer
turn of tape is between 1.59 cm and 0.64 cm (0.63 in and 0.25 in) from the outer edge of the reel
(Figure 2-3). Thus 267 mm (l0.5 in) reels which do not contain sufficient tape, must follow the manual
load procedure.

-=------.:'r---- LAST TURN OF TAPE

15.875 MM: 6.35 MM
(0.625 INCH: 0.250 INCH

MA-2654

MANUAL LOAD
PROCEDURE
(PARAGRAPH 2.2.4)

Figure 2-3

AUTO LOAD
PROCEDURE
(PARAGRAPH 2.2.3)
MA-27636

Figure 2-2

Autoload/Manual Load Selection

2-3

Tape Content Limit

2.2.3 Autoload
Follow the steps below in order to perform the autoload procedure.
l.

Check that the tape path is clean. (Refer to Paragraph 4.3.4 for cleaning procedure.)

Check that the tape is a 267 mm (10.5 in) reel, and that it has a full red of tape.

Check that the end of tape has a clean edge and is not bent, torn, or frayed. If necessary, trim
the end with the tape crimper (PN 47-00038).
NOTE
Do not crimp the tape unnecessarily. Each crimping
shortens the tape leader and could eventually lead to
failures in the autoload sequence.

Check that static charge is not causing end of tape to stick to reel. End of tape must be free
of reel to accomplish autoload.

If a write operation is to be performed, install a write enable ring onto the rear flange of the

tape reel.
6.

Place the supply reel in position on the upper hub. Rotate until it slips easily into place, and
press the reel retaining actuator. The reel should be positioned so that the tape unwinds if it
is turned clockwise.
NOTE
The supply reel may be contained in an Easy-Load®
wraparound cartridge. It is not necessary to remove
or open the cartridge. It opens automatically during
the autoload sequence.

Carefully close the buffer door. Make sure it is closed securely.

Close the transport front door.

Check that power is applied to the tape transport (power light on).

10.

Follow the instructions and check for the events specified in Figure 2-4. If the tape fails to
load properly, the figure contains some operator troubleshooting hints that can be tried before maintenance personnel are called. Refer to Figure 2-5 to identify tape path components.

2.2.4 Manual Load
Follow the steps below in order to perform the manual procedure.
1.

Check that the tape path is clean. (Refer to Paragraph 4.3.4 for cleaning procedure.)

If a write operation is to be performed, install a write enable ring onto the rear flange of the
tape reel.

®Easy-Load is a registered trademark of IBM, Inc.

2-4

CARTRIDGE (IF ANY)
WILL OPEN. TAKE UP
REEL WILL START
TOTURN CWo

NO
TAPE ENTERS
VACUUM COLUMNS
AND LOOPS ARE SET.

INSTALL A BOT
MARKER 4.6 M (15 FT.)
FROM THE BEGINNING
OF THE TAPE.
REPEAT THE AUTOLOA
PROCEDURE.

SUPPLY REEL WILL
TURN BACKWARDS
(CCW) A FEW TURNS
AND THEN ROTATE
FORWARD (CW) AND
EJECT TAPE INTO
THE TAPE PATH.

TAKE UP REEL
COMPLETES ABOUT
YES
NO

tv
I

BACKWINDS THE TAPE
AND STOPS.

ALL THE TAPE AND
THEN ROTATES
FORWARD
EJECTING TAPE INTO
THE TAPE PATH.

TAKE UP REEL
STOPS. LOAD FAULT
LAMP FLASHES ON
AND OFF.

YES

CHECK PARAGRAPH
2.2.5 FOR PROBABLE
CAUSE. ATIEM PT
ANOTHER AUTOLOAD.

REPEAT THE
AUTOLOAD
PROCEDURE
WITH ANOTHER
REEL OF TAPE. IF
THE LOAD SEQUENCE
IS STILL
UNSUCCESSFUL. CALL
MAINTENANCE
PERSONNEL.

I F THE AUTOLOAD
PROCEDURE FAILS
AGAIN. REPORT
PROBLEM TO
MAINTENANCE. TO
CONTINUE
OPERATION.
TRY LOADING THE
TAPE MANUALLY
A

(PARAGRAPH 2.2.4)

BOT MARKER IS TOO FAR FROM BEGINNING OF
TAPE. MARKER SHOULD· BE FROM 4.3 TO 4.9 M
(14 TO 16 FT.) FROM BEGINNING OF TAPE. RE·
POSITION THE MARKER AND REPEAT THE AUTOLOAD
PROCEDURE OR. IF IT IS DESIRED TO CONTINUE
OPERATION. ROTATE THE TAKE UP REEL UNTIL
THE BOT MARKER IS ON THE REEL. PERFORM
A MID-REEL LOAD BY ROTATING THE
TAKE UP REEL TO REMOVE ALL SLACK IN THE
TAPE. WITH THE TAPE TIGHT. PRESS THE
RESET BUnON AND THEN THE LOAD/REW BUTION.

YES

DONE
MA-2657A

Figure 2-4

Autoload Sequence with Operator Troubleshooting

LOAD FAULT
INDICATOR
FILE PROTECT
INDICATOR
ON LINE
INDICATOR
BOT
INDICATOR
POWER

PORT SELECT

.+--;--=---:---;.--:-- EOT IBOT SENSO R
TAPE IN PATH
SENSOR
TAKE UP
BUFFER BOX

6250 INDICATOR
1600 INDICATOR
PACK SENSEI
LOW-TAPE SENSOR
TABS (IN REEL)

TAKE UP REEL

HEAD

LOW-TAPE SENSOR
(BEHIND REEL)

Figure 2-5

TAPE CLEANER
MA·2640A

Tape Path and Controls

Manually place the tape leader between thread block 1 and air bearing 1 (Figure 2-5).

NOTE
Make sure that there is no tape slack or sag between
the supply reel and thread block 1.
5.

Close the transport front door.

Check that power is applied to the tape transport (power light is on).

Follow the instructions and check for the events specified in Figure 2-6. If the tape fails to
load properly, the figure contains some operator troubleshooting hints that can be tried before maintenance personnel are called. Refer to Figure 2-5 to identify tape path components.

2-6

INSTALL A BOT
MARKER 4.6M (15 FT.I
FROM THE BEGINNING
OF THE TAPE.
REPEAT THE MANUAL
LOAD PROCEDURE.
NO

BOT MARKER IS TOO FAR FROM BEGINNING OF
TAPE. MARKER SHOULD BE FROM 4.3 TO 4.9M
(14 TO 16 FT.I FROM BEGINNING OF TAPE. RE·
POSITION THE MARKER AND REPEAT THE MANUAL LOAD
PROCEDURE OR, IF IT IS DESIRED TO CONTINUE
OPERATION, ROTATE THE TAKE UP REEL UNTIL
THE BOT MARKER IS ON THE REEL. PERFORM
A MID·REEL LOAD BY ROTATING THE
TAKE UP REEL TO REMOVE ALL SLACK IN THE
TAPE. WITH THE TAPE TIGHT, PRESS THE
RESET BUnON AND THEN THE LOAD/REW BUnON.

TAPE ENTERS
VACUUM COLUMNS
ANO LOOPS ARE
SET.

YES

TAKE UP REEL
STOPS. LOAD FAU L T
LIGHT FLASHES ON
AND OFF.

CHECK PARAGRAPH
2.2.5 FOR PROBABLE
CAUSE. ATTEMPT
ANOTHER MANUAL
LOAD. IF THE
MANUAL LOAD
PROCEDURE FAILS
AGAIN. CALL
MAINTENANCE
PERSONNEL.

REPEAT THE MANUAL
LOAD PROCEDU RE
WITH ANOTHER
REEL OF TAPE.
IF THE LOAD
SEQUENCE IS STILL
UNSUCCESSFUL. CALL
MAINTENANCE
PERSONNEL.

YES

DONE

Figure 2-6

Manual Load Sequence with Operator Troubleshooting

2.2.5 Probable Causes of Load Failure
The following is a list of procedures for repairing load failure.
1.

Check that the buffer door is closed and sealed properly.

Check that the front door is closed securely.

Check for ripped, creased, or damaged tape leader. This is especially critical if an autoload
failure has occurred. If necessary crimp the end of the tape with a tape crimper.

Check that the write enable ring is inserted in the tape reel if a write operation is to be performed. (File protect indicator should be out.)

If an autoload is being performed, check the following.
a.

A 267 mm (10.5 in) tape reel is on the supply hub

The supply reel has a full reel of tape. The tape must be between 0.64 cm and 1.59 cm
(0.25 in and 0.63 in) from the outer edge of the reel.

2-7

2.2.6 Midreel Load
A midreel load is usually required after a power failure or a lost interlock. Follow the steps below to
perform a midreel load.
1. Rotate the take-up reel to remove all slack in the tape.

CAUTION
Do not attempt mid reel load until all slack is manually removed from the tape between the reels.
2. Press the RESET button.
3. Close the front door.
4. Press the LOAD /REW button.
The transport loads the tape and starts a reverse operation to BOT. To stop the transport, press the
RESET button. Any other command may now be given.
2.2.7 Unload
Follow the steps below to unload a tape.
1.

Press the RESET button to terminate any current operation and place the: transport off-line.

Press the UNLOAD button. If the tape is at BOT, it backwinds onto the supply reel. If the
tape is at midreel, it rewinds to BOT and then unloads (backwinds onto the supply reel).

2.2.8 Rewind
Press the LOAD /REW button, with tape tensioned and the transport off-line, to rewind the tape to
BOT. When the button is pressed with the tape at BOT, no action occurs.
2.2.9 On-LinejOff-Line
Press the ON LINE button to place the transport on-line. This lights the on-line indicator. While online, the transport can accept external commands provided it is selected and ready. If the ON LINE
button is pressed again, the transport goes off-line. The on-line indicator goes out. Also, the transport
automatically goes off-line when any of the following conditions occur.
• An external rewind unload command is received
• Vacuum column interlock is broken
• AC power is lost
• RESET button is pressed
• Front door opens

2-8

CHAPTER 3
INSTALLATION

3.1

SITE PLANNING

3.1.1 Space Requirements
Figure 3-1 illustrates the space and service clearances required for the TU78 cabinet. There must be
enough space to swing the TM78 out of the cabinet for servicing and open the front and rear doors on
the TU78 tape transport.
3.1.2 Power Requirements
The TU78 tape transport can be operated from 188 Vac to 256 Vac at 60 Hz, or 198 Vac to 256 Vac, at
50 Hz, with proper connections on the power chassis. Line voltage should be maintained to within ± 10
percent of the nominal value. Frequency should not vary more than ± 1 Hz.

~----y---

_ _ _ _ 69.2 eM
,
___

" "-

64.1 eM
(25-1/4 IN.)

{:25IN.I

REAR DOOR

\
+

144.8 eM
(57 IN.)

+
REMOVABLE SIDE PANEL

76.2 eM
(30 IN.)

L~+

-----I

/
53.3 eM
(21 IN.)

L
Figure 3-1

BASE ASSEMBLY

---

/
MA-2641

Space and Service Clearance (Top View)

3-1

3.1.3 Environmental Requirements
The TU78 transport should be located in an area free of excessive dust, dirt, corrosive fumes, and vapors. The bottom of the cabinet, and the air vents in the front panel and rear door of the cabinet, must
not be obstructed. The operating environment should have cool, well-filtered, humidified air. A temperature range of 15° to 27° C (59° to 80° F); and relative humidity of 40 to 60 percent should be maintained.
3.2

UNPACKING AND INSPECTION

3.2.1 Unpacking
The TU78 cabinet(H9500)comes mounted to a shock absorbing wooden shipping skid that measures
approximately 76 cm (30 in) wide, 107 cm (42 in) long, and 15 cm (5.75 in) high. The cabinet comes
packed in an extra strong corrugated cardboard container that measures approxilnately 76 cm (30 in)
wide, 89 cm (35 in) long, and 147 cm (58 in) high. (Units shipped outside the continental United States
have an additional wooden container around the cardboard carton. The side panels of the container are
bolted together.) Also mounted to the shipping skid are two wooden ramps which are repositioned during the unpacking procedure so that the cabinet may be rolled off the skid.
To unpack the TU78 from its shipping container, and remove the shipping skid, perform the following
procedure. (Refer to Figure 3-2).
1.

Cut and remove the plastic bands around the cardboard container. Remove the angle boards.

Cut the tape on the top and sides of the container.

Remove and dispose of the container. (It is not reusable.)

Remove the plastic bag from the cabinet.

Two hex head bolts hold the wooden ramps to the shipping skid. Unfasten the ramps by removing the bolts and associated washers. Both ramps are positioned between the TU78 cabinet and the shipping skid, and are visible from the front of the cabinet.

Slide the ramps out from under the cabinet and set them aside for assembly (step 9).

Unbolt the cabinet from the shipping skid. Remove four hex bolts that hold the cabinet
frame to the skid deck (Figure 3·3). Discard the bolts, washers, and nuts.

Remove and discard the three wooden block spacers located between the cabinet frame and
the skid deck. (Figure 3-3).

Attach the two wooden ramps to the skid deck. Four tee nuts have been driven into the top of
the skid deck on the left side for this purpose. (Refer to the exploded view of Figure 3-2
showing mounting details). Position the aluminum bracket of one mounting ramp underneath
the skid deck so that the holes in the bracket are lined up with the tee nuts. Fasten the
bracket to the skid deck with two 1/4-20 X 3/4 hex bolts. (The bolts are shipped in the
accessory package.) Attach the second ramp to the skid deck in the same manner.
CAUTION
The following step requires two people to roll the
TU78 down the wooden ramps. The majority of the
weight of the TU78 is situated in the upper half of
the cabinet, making it top-heavy. Do not attempt
this procedure with only one person.
3-2

CONTAINER,
REMOVE AND DISPOSE

CD
POLYESTER TAPE,
CUT

RAMPS, ATTACH TO
SKID DECK
HEX

SCRE~d::h
MA-7015

Figure 3-2

Unpacking the TU78

10.

Roll the TU78 toward the left side of the side deck by pushing gently on the right side of the
cabinet. With one person bracing a shoulder against the left front and the other person bracing a shoulder against the left rear of the cabinet, allow it to roll off the skid deck, down the
wooden ramps and onto the floor.

11.

Unfasten the wooden ramps. Discard them and the shipping skid.

3.2.2 Inspection
After unpacking the TU78 transport, inspect it and report any damage to the responsible shipper and
the local DIGITAL sales office. Perform the inspection according to the following steps.
1.

Inspect all switches, indicators, and panels for damage.

3-3

NYLOCK NUT

SKID DECK

SQUARE WASHER
MA-7016

Figure 3-3

TU78 Mounting for Shipment

Open TU78 front door. Fully depress the upper and lower release buttons and open the buffer box door. Check that the buffer box door is tightly secured to the cabinet. Inspect for
foreign material, loose or damaged components, and for glass damage.

Check the transport for any foreign material that may have lodged in the take-up reel or
other moving parts.

Rotate the supply hub and take-up reel. Check for binding and physical damage.

Rotate the capstan. Check for binding and physical damage.
CAUTION
The capstan is fragile. Do not touch the capstan rubber surface and do not apply pressure to the capstan
which might cause it to deform.

3.3

Check tape path for any sharp edges.

Close the buffer box door by pressing the two release buttons using moderate pressure. (The
buttons will not catch if pressed too hard.)

Close the TU78 front door.

SINGLE TRANSPORT INSTALLATION

3.3.1 Mechanical Installation
After the shipping container and skid have been removed and visual inspection has been performed, roll
the transport cabinet into position and proceed as follows.
NOTE
If the TU7S is placed next to another system cabi-

net, do not remove the adjoining side panels and bolt
the cabinets together. Rather, leave the side panels
3-4

INTERLOCK
ROD

~~LEVELER
i~~ FO~
Figure 3-4

11-5612
MA-7017

Location of Stabilizer Arm and Leveler Feet

on and position the TV78 side panel tight aga,inst
the other cabinet's side panel. This maintains proper
air flow in both cabinets.
1.

An array of vertical slots constitutes the venting in the cabinet front panel. A quick release
latch is located approximately 2.54 cm (1 in) behind each end of this array. Insert a thinbladed tool (such as a small steel rule) into one of the end slots, and push on the latch while
simultaneously pulling forward to release one corner of the front panel. In the same manner,
while continuing to pull forward, release the latch at the other end of the array to free the
front panel. Remove the front panel and set it aside. Do not disconnect the ground strap from
the panel.

Remove the two leveler pads and four leveler feet that are blister wrapped wrap and taped to
the inside of the front panel.

Raise the interlock rods on each side of the cabinet. Remove the two stabilizer arms from the
stabilizer sleeve assemblies (Figure 3-4).

Screw the leveler pads into the stabilizer arms.

Raise the interlock rods. Reinsert the stabilizer arms into the stabilizer sleeve assemblies.

Install the leveler feet in the lower corners of the cabinet frame (Figure 3-4).

3-5

MIA PCB

READ PCB

WRITE PCB

CONTROL M2PCB

PUSH>

CAPSTAN SERVO PCB
REEL SERVO PCB
MA-2645A

Figure 3-5

PCB Shipping Bracket (Side View)

Using a 9/ 16-inch wrench, lower the leveling feet until they make contact with the floor
stabilizing the cabinet.

Using a level, adjust the feet until the cabinet is level.

Extend the two stabilizer arms and lower the leveler pads until they just touch the floor yet
can easily slide along the floor. Do not place any weight on the leveler pads.

10.

Insert a 5/32-inch Allen wrench into the rear door latch, and turn one-'quarter turn in a
counterclockwise direction. Open the door.

11.

Open the transport front door and the buffer box door. Using a screwdriver, release the service lock located in the lower right corner of the base assembly. Swing the base assembly
open.

NOTE
The base assembly does not swing open unless the
stabilizer arms are extended (step 9).
12.

Remove the PCB shipping bracket by pushing in on the lower front and pulling down from
underneath (Figure 3-5).

3-6

REMOTE SENSE CABLE
( 70 - 08288 - 30 F ) IN

@....

~=========~DREMOTE SENSE CABLE (70- 08288- 8F)

FROM HOST CPU

~n::r=;n

OUT TO NEXT TU78

~~ Gi)
~ ~I
~ U
0

. .. .

of ~
Hj~

CABINET EXHAUST
BLOWERS

PNEUMATIC
SYSTEM HEAT
u...;;=~=~~rt-'-' EXCHANGE R

POWER PACK

CONTROLLER

PLUG
( N EMA L6 - 30P )

r -

-D~E~B:;- -

I
I

TM78
LOGIC
GATE

~I~I----~

~=========I FAN

I
I
I
I

L ______ ~8!!!TE~L~ .....J
MA-7018

Figure 3-6

TU78 Power Distribution

13.

Check seating of PCBs in their sockets.

14.

Replace the PCB shipping bracket.

3.3.2 Power and Cabling
Figure 3-6 shows the TU78 ac power distribution system. Refer to this figure while making the following checks.
1.

Check the following internal power cabling connections.
a.

Power cable from 874-E power controller switched outlet to transport power pack (Figure 3-6).

Power cable from 874-E switched outlet to cabinet exhaust blowers.

Power cable from 874-E switched outlet to pneumatic system heat exchanger blowers.

Power cable from 874-E switched outlet to H7422 power supply (master TU78 only).

3-7

POWER ON / OFF
CIRCUIT

POWER AVAILABLE
INDICATOR

REMOTE SWITCHING
BUS JACKS

0-\ ~~~·~a.mO

o 0 0
rii'Y'iiln) REMOTE

~_ _o_ _

~_o_0_~tO~

o_ _ _

a. FRONT PANEL

LOCAL

[

REMOTE / LOCAL
SWITCH

a. Front Panel

SWITCHED OUTLETS

UNSWITCHED OUTLETS

/l~

~{Bl

r::>:.
~
~ ~()
. 4 W~

~
<:::>()
~

~()

<:::>0
~

b. REAR PANEL

MA-7020

b. Rear Panel

Figure 3-7

874-E Power Controller

Power cable from 874-E switched outlet to TM78 logic cage blower.

DC power cable harness from H7422 power supply to TM78 logic gate (master TU78
only).

Check that the power on/off circuit breaker on the 874-E is on and the renl0te/local switch is
set to remote. (Figure 3-7).

Check fuses on power pack fuse panel (Figure 1-5). It is necessary to swing the TM78 logic
gate out on its hinge. The fuses can be seen from the front of the cabinet.

Remove the cover from the power transformer terminal strip (Figure 3-8). (The ac input plug
on power pack must also be removed.) Check that the blue, brown, and white/red wires are
connected to the lower terminals (Table 3-1). The terminals are numbered 1 through 9, from
left to right. Replace the cover and connect the power pack connector.

Check that the circuit breaker on therear of the power pack is in the on (up) position.

Remove the pulley cover from the rear of the transport power pack (Figure 3-8). Spin the ac
motor pulley by hand and check that the blower and compressor belts are tight and track
properly.

3-8

POWER TRANSFORMER
TERMINAL STRIP

TERMINAL NO.9

CIRCUIT

MOTOR
PULLEY

BLOWER
PULLEY

Figure 3-8

MA 2663A

Rear of Power Pack with Pulley Cover Removed

Table 3-1

Primary Power Connections

Input Voltage

Blue wire

Brown Wire and
White IRed Wire

198 - 205
206 - 215
216 - 225
226 - 235
236 - 245
246 - 255

TBI-4
TBI-3
TBl-4
TBl-3
TBl-4
TBl-3

TBI-7
TBI-7
TBI-8
TBl-8
TBI-9
TBI-9

NOTE
All TV7S transports are manufactured to operate in
the 0 to 610 m (0 to 2000 ft) range. If the transport
you are installing is to operate at higher elevations,
you must install one of the optional high altitude kits
listed below. If not, replace the pulley cover.
The following optional high altitude kits are available.
• 610 to 1220 ill
60 Hz
(PN A2W-0476-J 0 or 29-23985)
(2000 to 4000 ft)
50 Hz
(PN A2W-0476-11 or 29-23982)

3-9

•

1220 to 1830 m
(4000 to 6000 ft)

60 Hz
50 Hz

(PN A2W-0477-10 or 29-23986)
(PN A2W-0477-11 or 29-23983)

•

1830 to 2133 m
(6000 to 7000 ft)

60 Hz
50 Hz

(PN A2W-0478-10 or 29-23987)
(PN A2W-0478-11 or 29-23984)

Refer to Table 3-2 for a list of parts and associated part numbers for each kit.

Table 3-2

Pulley /Belt Part Numbers for Altitude Changes

Altitude

Freq.

Blower
Belt

Compressor
Belt

AC Motor
Pulley

Compressor
Pulley

610-1220 m
(2000-4000 ft)

60Hz
50 Hz

108479-03
108479-05

108479-01
108479-08

108478-06
108478-12

102635-03
102635-03

1220-1830 m
(4000-6000 ft)

60 Hz
50 Hz

108479-03
108479-12

108479-01
108479-08

108478-07
108478-11

102635-03
102635-03

1830-2133 m
(6000-7000 ft)

60 Hz
50 Hz

108479-11
108479-12

108479-01
108479-01

108478-08
108478-13

102635-05
102635-05

Note:Vendor part numbers shown

NOTE
If the altitude kit is being installed on a TU78 with a
serial number lower than SP02386, you must also
install a new blower assembly (PN 29-24013).
Install the high altitude kit in the following way.
a.

Turn transport power off at the cabinet power controller. Disconnect the ac line at the
rear of the power pack by pulling the plug straight out.
CAUTION
Do not attempt this or any other removal or replacement procedure within the power pack assembly
without first removing the 220 V power cord.

Remove the belt guard. Remove both belts by manually rotating the pulleys clockwise,
and slipping the belts off the larger pulleys. It is not necessary to loosen any compressor
or blower mounting screws.

Remove the pulley set from the ac motor shaft. Save the smaller pulley (hub) for the
installation. Replace the larger pulley with the appropriate pulley from the high altitude
kit. Reinstall the pulleys on the motor shaft.

Remove the pulley from the compressor shaft and replace it with the proper high altitude compressor pulley.

Replace the belts with the appropriate high altitude belts. Rotate the belts clockwise by
placing a belt around the smaller pulley and rotating it onto the larger pUlley. If too
tight or too loose, adjust the position of the blower or compressor.
3-10

(TOP VIEW)

TU78 UNIT 0
(MASTER)

TM78 LOGIC
GATE OPEN

TU78 UNIT 1
(SLAVE)

TU78 UNIT 2
(SLAVE)

TU78 UNIT 3
(SLAVE)

- - ___ VIEWING ANGLE

------

MAINTENANCE
KEYPAD / DISPLAY

Figure 3-9

Cabinet Placement for Maintenance Display Visibility

Check that both belts track completely on the pulleys. If not, some shift of the motor
pulleys may be necessary.

Replace the belt guard and the power cord.

Package the old belts and pulleys in a marked container, and leave it in the base of the
transport. It is possible that the transport may be moved to a lower altitude in the future.
NOTE
For the following two steps, refer to the procedures
found in the installation section (Chapter 3) of the
TM78 User Guide or Technical Manual.

3.4

Connect the BC06S round MASSBUS cable to the input port connector.

Connect a MASSBUS terminator to the output port connector.

Connect the remote switching control bus from the CPU to one of the front jacks on the 874E.

10.

Using the green/yellow ground cable provided, ground the TU78 cabinet frame to the CPU
cabinet frame. The grounding studs for the TU78 are located on the lower side frame members (Figure 3-11).

II.

Replace the front panel. Close the rear door.

12.

Check that system power is off at the CPU. Connect the ac power cable from the 874-E to
the power source.

13.

Perform acceptance testing (Paragraph 3.5).

MULTIPLE TRANSPORT INSTALLATION

3.4.1 Mechanical Installation
When an installation requires more than one transport, only the master transport is shipped with the
side panels. During installation, remove one of the side panels, and bolt the master and slave transport(s) together. Then mount the removed side panel onto the end slave transport.

3-11

After removing the shipping containers and skids, perform the visual inspection of the transports. Then
roll the transport cabinets into their approximate positions. Place the master transport to the left (facing front) of all other transports. This allows the TM78 keypad/display to be seen from the other transports in the line when the logic gate is swung out (Figure 3-9).

NOTE
If the TV78 on either end is placed next to another
system cabinet, do not remove the adjoining side
panels and bolt the cabinets together. Rather, leave
the side panels on and position the TV78 side panel
tight against the other cabinet's side panel. This
maintains proper air flow in both cabinets.

Unless otherwise specified, perform the installation of each cabinet as follows.
1.

Remove the two leveler pads and four leveler feet that are blister wrapped and taped to the
inside of the front panel.

Raise the interlock rods on each side of the cabinet. Remove the two stabilizer arms from the
stabilizer sleeve assemblies (Figure 3-4).

Screw the leveler pads into the stabilizer arms.

Raise the interlock rods. Reinsert the stabilizer arms into the stabilizer sleeve assemblies.

Install the leveler feet in the lower corners of the cabinet frame (Figure 3-4).

Extend the two stabilizer arms from each cabinet and lower the levelt::r pads until they just
touch the floor. Do not place any weight on the leveler pads.

Open the master transport front door. Using a screwdriver, release the service lock located in
the lower right corner of the base assembly. Swing the base aS~'eml'ly open.

NOTE
The base assembly will not swing open unless the
stabilizer arms are extended (step 7).
9.

Locate the fastener attached to the underside of the master transport top cover (Figure 3-10).
Release the top cover by turning the fastener one-quarter turn in a counterclockwise direction. When it is released, the fastener hangs by a wire from the top cover. Pull the top cover
forward approximately 1.27 cm (0.5 in) and lift it off. Rest the cover on top of the cabinet,
leaving the ground wire connected.

10.

Remove the end panel on the right side by grasping it on both sides and lifting it off the four
mounting bolts. If the side panel does not lift off, it may be necessary to loosen the mounting
bolts. In this case, remove the front panel trim to gain access to the upper front mounting
bolt. To remove the trim, lift it up and out (Figure 3-11).
3-12

Figure 3-10

Top Cover Fastener

GROUNDING
STUDS
MOUNTING BOLTS

Figure 3-11

MA·2661

Cabinet with Side Panels and Top Cover Removed

11.

Disconnect the side panel ground strap from the cabinet frame and set the panel aside.

12.

Remove the four exposed mounting bolts from the master transport.

13.

Push the cabinets together so they are in adjoining positions with the mounting bolt plates
side by side.

14.

Using the short ground strap included with the slave transports, ground the master and slave
cabinets together.

15.

Using the green/yellow ground cable provided with the master, ground the master TU78
cabinet frame to the CPU cabinet frame.
3-13

( FRONT VIEW)

'-----1

L___

TM78J

TU 0 ( MASTER)

TU 2 (SLAVE)

TU 1 (SLAVE)

TU 3 (SLAVE)

NOTE:
ROUTE CAB LES
UP THROUGH SPACE
BETWEEN CABINET
FRAMES.

Figure 3-12

MA·7022

TU Bus Cable Routing for a Multiple Transport
Configura tion

16.

Using a 9/ 16-inch wrench, lower the leveling feet of the highest cabinet until they make contact with the floor stabilizing the cabinet.

17.

Using a level, adjust the feet until the cabinet is level.

18.

Level and adjust the adjoining cabinet(s) so that the bolting (middle) holes on the four corner
bolting plates are aligned.
NOTE
Before performing the next step, the TU bus cables
for all slave transports must be laid in loosely between the master and first slave (Figure 3-12). There
are two 4.6 m (15 ft) cables (PN 70-17382-15) for
each slave. Orient the cables so that the red stripe on
the side faces the rear of the cabinet. Do not tape the
cables together since this would inhibit the replacement of a single cable in the event of failure.

19.

Insert 1/ 4-inch bolts into the holes and secure them with kep nuts. Bolting the cabinets in this
manner provides good horizontal alignment.

20.

Readjust the leveler pads on the stabilizer arms until each pad touches, yet easily slides along
the floor. Do not place any weight on the leveler pads.

21.

Install the four mounting bolts from the master cabinet into the mounting bolt plates of the
end slave transport. Remove front panel trim if necessary.

22.

Open the base assembly of the end slave transport. Release the top cover fastener, remove
the cover, and rest it on top of the cabinet, off to one side. Do not disconnect the cover
ground strap.

23.

Set the side panel from the master transport next to the slave transport. Connect the panel
ground strap to the cabinet frame. Mount the panel onto the side of thc~ slave transport.
3-14

24.

Replace the top cover and secure the cover fastener.

25.

Insert a 5/32-inch Allen wrench into the rear door latch. Turn it one-quarter turn in a
counterclockwise direction and open the door.

26.

Open the base assembly of each transport. Remove the PCB shipping bracket by pushing in
on the lower front and pulling down from underneath (Figure 3-5). Check seating of PCBs in
their sockets. Replace the PCB shipping bracket.

3.4.2 Power and Cabling
Figure 3-6 shows the TU78 ac power distribution system. Refer to this figure while making the following checks.
1.

Check the following internal power cabling connections for all the transports.
a.

Power cable from 874-E power controller switched outlet to transport power pack (Figure 3-6).

Power cable from 874-E switched outlet to cabinet exhaust blowers.

Power cable from 874-E switched outlet to pneumatic system heat exchanger blowers.

Power cable from 874-E switched outlet to H7422 power supply (master TU78 only).

Power cable from 874-E switched outlet to TM78 logic cage blower (master TU78
only).

DC power cable harness from H7422 power supply to TM78 logic gate (master TU78
only).

Check that the power on/off circuit breaker on the 874-E is on and the remote/local switch is
set to remote (Figure 3-7).

Check fuses on power pack fuse panel (Figure 1-5). The fuses can be seen from the front of
the cabinet. (On the master transport, it is necessary to swing the TM78 logic gate out on its
hinge.) A closer view can be obtained from the :rear of the cabinet by looking over and down
onto the fuse panel.

Remove the cover from the power transformer terminal strip (Figure 3-8). (The ac input plug
on the power pack must also be removed.) Check that the blue, brown, and white/red wires
are connected to the lower terminals (Table 3-1). The terminals are numbered 1 through 9,
from left to right. Replace the cover and connect the power pack connector.

Check that the circuit breaker on the rear of the power pack is in the on (up) position.

Remove the pulley cover from the rear of the transport power pack (Figure 3-8).

NOTE
All TU78 transports are manufactured to operate in
the 0 to 610 m (0 to 2000 ft) range. If the transport
you are installing is to operate at higher elevations,
you must install a high altitude belt and pulley kit.
Refer to Paragraph 3.3.2, step 6 for instructions.

3-15

TU BUS OA
TU 0 MIA
TU BUS OB
0000

TU BUS 1A
TU 1 MIA
TU BUS 1B
0000

TU BUS 2A
TU 2 MIA
TU BUS 2B
0000

TU BUS 3A
J8

~____________~_T~U_B_U_S~3B__~____

TM78 BACKPLANE
MA-6172

Figure 3-13

Radial TU Bus Connections

Spin the ac motor pulley by hand and check that the blower and compressor belts are tight
and track properly. Replace the pulley cover.
NOTE
For the following two steps, refer to the procedures
found in the installation section (Chapter 3) of the
TM78 User Guide or Technical Manual.
7.

Connect the BC06S round MASSBUS cable to the input port connector.

Connect a MASSBUS terminator to the output port connector.

Install the TU bus cables between the TM78 in the master transport and the slave transport(s). Figure 3-12 shows the positioning of the cables relative to the cabinet frames. The
TV bus for the master transport is prewired at the factory. Figure 3-13 shows the electrical
connection for each TV bus cable. Start at the TM78 end of the cable and work toward the
MIA (multiple interface adapter) end.
NOTE
The procedure for connecting. the cable to the TM78
is found in the installation section (Chapter 3) of the
TM78 User Guide or Technical Manual.
3-16

MA-7023

Figure 3-14

Cable Orientation on TU78 MIA PCBA (Slave Only)

10.

The TU bus cables should exit up through the space between the frame members of the master and first slave transports. (Refer to note after Step 18, Paragraph 3.4.1). Fold all cables
over and thread them through the space between the cabinet frame and the transport card
cage side panels. The cables should lie flat over the MIA PCBs.

11.

Dress and bend the cables as shown in Figure 3-14. Note the orientation of the red stripe.
Plug the appropriate cables into the two MIA jacks (J2 and J3). Any slack in the cables
should be taken up, folded, and tie-wrapped.

12.

Repeat this procedure for each set of cables going to each slave transport. The cables for
each succeeding transport should be layed over the preceding transports MIA card (Figure 312).

13.

Daisy chain the remote switching control bus by connecting the bus from the CPU to one of
the jacks on the front of the master transport's 874-E power controller. Using another cable,
connect the bus from one of the other jacks on the 874-E to the 874-E in the next transport.
Continue the daisy chain until all the TU78s are connected to the remote switching control
bus.

14.

Check that system power is off at the CPU. Connect the ac power cable from each 874-E to a
power source.

15.

Install cabinet front panels, and close and secure all base assemblies.

16.

Perform acceptance testing (Paragraph 3.5).

3.5 ACCEPTANCE TESTING
This section describes all the acceptance tests required for the TU78 transport and the TM78 tape
formatter. If they are performed satisfactorily, then the units have been installed and are operating
properly.
Acceptance testing is divided into three categories: turn-on and loading checkout, subsystem quick
check, and system level diagnostics. The turn-on and loading checkout verifies only basic functions of
the transport and formatter. The subsystem quick check involves calling certain microcoded test routines from the TM78 maintenance panel. The system level diagnostics treat the formatter and transport
as a subsystem, and exercise them to the fullest extent.
3-17

If unfamiliar with interlocks and other conditions affecting autoload/manual load selection, refer to
Paragraph 2.2.2.

3.5.1 Turn-On and Loading Checkout
The turn-on and loading checkout applies power to the subsystem in order to observe the state in which
the formatter comes up running and the transport comes up idle. This test also loads the transport under
various conditions in order to check for the proper responses. The checkout utilizes flowcharts to show
the proper sequence of events for each loading operations. The flowcharts include minor troubleshooting aids to help locate simple problems caused by bad tape or improper loading procedures. Perform the following operations in order.
3.5.1.1

Power On - Follow the instructions and check for the events specified.

Remove the lower front panel of the master transport to gain access to the TM78 formatter.

Turn both TM78 MASSBUS ports off-line by flipping TM78 backplane DIP switches 1 and
5 to the right (0) position.

Turn on power. This may be done remotely by turning on the host CPU, or locally by flipping
the REMOTE/LOCAL switch located on the 874-E to LOCAL ON.

Check for the following.
a.

All fans in subsystem turn on.

The following indicators on the TU78 control panel light: Power, File Protect, 6250. All
other lights on the TU78 control panel remain unlit.

The internal microcomputer exercises the TM78 maintenance panel display. This exercise consists of rotating the following characters through all six LEDs in the display: 0,
1,2,3, 4, 5, 6, 7, -, H, E, L, P. The rotating display allows you to check that each LED
can produce each available character. It also indicates that the internal microcomputer
is running.
If the display does not rotate the characters, press and release the TM78 master reset
button, located on the backplane just to the right of the DIP switches. If the display still
does not rotate the characters, this indicates that there is a TM78 logic or power supply
malfunction (assuming that the TM78 is off-line). Refer to the troubleshooting procedures found in chapter 5 of the TM78 Technical Manual.

Perform the TM78 maintenance keypad tests. Press each key (except ENA) independently in
order to produce its keypad matrix location in the display. The second LED digit indicates
the column number and the fifth LED indicates the row number. The other LEDs display
hyphens. Figure 3-15 illustrates the keypad with the assigned column and row numbers.
When no key is pressed, the display reverts to the rotating character test.
Now press the ENA (enable) key firmly for one second. This stops the microcomputer from
running the maintenance display/keypad tests and display HELLO in the LEDs. Now the
keypad is enabled and the microcomputer is waiting for a command. Press ENA again and
the microcomputer disables the keypad and the display goes blank.

3.5.1.2 Load Sequence Without Tape - With no tape reel mounted on the supply hub and the front
door closed, follow the instructions and check for the events specified in Figure 3-16.

3-18

COLUMNS
2

[EXE)

(2]

[ENA}

I~)

000

IHDW)

[STA)

QJ0QJ [~)

[~)

ROWS

[ClR)

[NXTJ

[DEPJ

[MEM)

r l

MA-7024

Figure 3-15

TM78 Maintenance Keypad

PRESS RESET
BUTTON.

SUPPLY HUB STOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE-ENERGIZE.
PRESS LOAD/REW
BUTTON.

!
SUPPLY HUB
ROTATES CCW.

'AC MOTOR STARTS.
TAKE UP REEL TURNS
CWo (NO SUPPLY HUB
MOTION.) CARTRI DGE
MOTOR OPENS.

!
PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

TAKE UP REEL STOPS.
SUPPLY HUB STOPS.
AC MOTOR STOPS.
PRESSURE AND VACUUM SOLENOIDS DEENERGIZE. lOAD FAULT
LAMP FLASHES ON
AND OFF.

SUPPLY HUB
ROTATES CWo

TAKE UP REEL
COMPLETES ABOUT
TEN REVOLUTIONS.

PRESS RESET
BUTTON.

!
CARTRI DGE MOTOR
CLOSES. lOAD FAULT
lAMP GOES OFF.
MA-2639

Figure 3-16

Load Sequence Without Tape

3-19

FILE PROTECTLAMPGOES
OFF. AC MOTOR
STARTS. CARTRIDGE
MOTOR OPENS. TAKEUP REEL TURNS CWo
(NO SUPPLY REEL
MOTION_)

SUPPLY REEL STOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE- EN ER G IZE.

PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

PRESSURE AND VACUUM SOLENOIDS DEENERGIZE. SUPPLY
REEL STOPS. TAKE-UP
REEL STOPS. AC MOTOR STOPS. LOAD FAULT
LAMP FLASHES ON
AND OFF. FILE PROTECT
LAM P COMES ON.

TAKE UP REEL
COMPLETES ABOUT
TEN REVOLUTIONS.

SUPPLY REEL STOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE-ENERGIZE.

MA-2649

Figure 3-17

Inhibited Autoload Sequence

3.5.1.3 Inhibited Autoload Sequence - Install a write enable ring on a 267 mm (10.:5 in) tape reel. Tape
the leader to prevent magnetic tape from coming off the reel. Mount the reel onto the supply hub. Close
the transport front door. Follow the instructions and check for the events specified in Figure 3-17.
3.5.1.4 Autoload Sequence - Remove the tape from the leader allowing the magnetic tape to come off
the supply reel. Check that the leader has no creases or rips. If necessary, crimp the end of the tape
with the tape crimper (PN 47-00038). Do not remove the write enable ring. Close the transport front
door. Follow the instructions and check for the events specified in Figure 3-18.

3-20

TAKE UP REEL
COMPLETES ABOUT
TEN REVOLUTIONS.

FILE PROTECT LAMP
GOES OFF. AC MOTOR
STARTS. CARTRIDGE
MOTOR OPENS.TAKEUP REEL TURNS CWo
(NO SUPPLY REEL
MOTION.)

PRESSURE AND
VACUUM SOLENOJDS
DE-EN ERGIZE.
INSTALL A BOT
MARKER 4.6M (15 FT.)
FROM THE BEGINNING
OF THE TAPE. REPEAT
THE AUTOLOAD PROCEDURE.

SUPPLY REEL STOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE-ENERGIZE.

SUPPLY REELSTOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE-ENERGIZE.

PRESSURE AND
VACUUM SOLENOIDS
PRESSU RE AND
VACUUM SOLENOIDS
ENERGIZE.

TAKE UP REEL
COMPLETES ABOUT
TEN REVOLUTIONS.

ENERGIZE.
REPEAT THE AUTOLOAD PROCEDURE
WITH ANOTHER REEL
OF TAPE. IF THE LOAD
SEQUENCE IS STILL
UNSUCCESSFUL. REFER TO TROUBLESHOOTING
PROCEDURES IN
CHAPTER 6 OF THE
TECHN ICAL MANUAL.

YES

BOT MARKER IS TOO
FAR FROM BEGINNING
OF TAPE. MARKER
SHOULD BE FROM 4.3
TO 4.9 M (14 TO 16 FT.)
FROM BEGINNING OF
TAPE. REPOSITION THE
MARKER AND REPEAT
THE AUTOLOAD PROCEDURE. IF THE SAME
PROBLEM OCCURS
AGAIN. REPEAT THE
PROCEDURE WITH ANOTHER REEL OF TAPE.
IF THE LOAD SEQUENCE IS STILL UNSUCCESSFUL. REFER
TO TROUBLESHOOTING PROCEDURES IN CHAPTER
6 OF THE TECHNICAL
MANUAL

PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

TAKE UP REEL STOPS.
SUPPLY REEL STOPS.
PRESSURE AND VACUUM SOLENOIDS DEENERGIZE. AC MOTOR
STOPS. LOAD F AU L T
LAMP FLASHES ON
AND OFF. FI LE PROTECT LAMP COMES ON.

CHECK PARAGRAPH
2.2.5 FOR PROBABLE
CAUSE. AHEM PT AN·
OTHER AUTOLOAD. IF
TH E AUTOLOAD PROCEDURE FAILS AGAIN.
REFER TO TROUBLESHOOTING PROCEDURES IN CHAPTER
6 OF TECHNICAL MANUAL.

MA·2658A

Figure 3-18

Autoload Sequence

TAKE UP REEL
COMPLETES ABOUT
TEN REVOLUTIONS.

SUPPLY REEL STOPS.
PRESSURE AND
VACUUM SOLENOIDS
DE-ENERGIZE.

FILE PROTECT LAMP
GOES OFF. AC
MOTOR STARTS.
CARTRIDGE MOTOR
OPENS. TAKE UP REEL
TURNS CW.(NO
SUPPLY REEL MOTION).

INSTALL A BOT
MAR KER 4.6M (15FT.)
FROM THE BEGINNING
OF THE TAPE. REPEAT
THE MANUAL LOAD
PROCEDURE.

PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

REPEAT THE MANUAL
LOAD PROCEDURE
WITH ANOTHER REEL
OF TAPE. IF THE LOAD
SEQUENCE IS STILL
UNSUCCESSFUL. REFER TO TROUBLESHOOTING
PROCEDURES IN
CHAPTER 6 OF THE
TECHNICAL MANUAL.

PRESSURE AND
VACUUM SOLENOIDS
DE-EN ERGIZE.

Figure 3-19

BOT MARKER IS TOO
FAR FROM BEGINNING
OF TAPE. MARKER
SHOULD BE FROM 4.3
TO 4.9M (14 TO 16 FT.)
FROM BEGINNING OF
TAPE. REPOSITION THE
MARKER AND REPEAT
THE MANUAL LOAD
PROCEDUR'E. IF THE
SAME PROBLEM OCCURS AGAIN, REPEAT
THE PROCEDURE WITH
ANOTHER REEL OF
TAPE. IF THE LOAD SEQUENCE IS STILL UNSUCCESSFUL, REFER
TO TROUBLESHOOTING PROCEDURES IN CHAPTER
6 OF THE TECHNICAL
MANUAL.

PRESSURE AND
VACUUM SOLENOIDS
ENERGIZE.

TAKE-UP REEL STOPS.
SUPPLY REEL STOPS.
PRESSURE AND VACUUM SOLENOIDS DEENERGIZE. AC MOTOR
STOPS. FILE PROTECT
LAMP COMES ON.
LOAD FAULT LAMP
FLASHES ON AND OFF.

CHECK PARAGRAPH
2.2.5 FOR PROBABLE
CAUSE. ATTEMPT
ANOTHER MANUAL
LOAD. IF THE MANUAL
LOAD PROCEDURE
FAILS AGAIN, REFER
TO TROUBLESHOOTING PROCEDURES IN CHAPTER
6 OF THE TECHNICAL
MANUAL.

Manual Load Sequence

3.5.1.5 Manual Load Sequence - Install a write enable ring on a 216 mm or 178 mm (8.5 in or 7 in)
tape reel. Mount the reel onto the supply hub. Check that the leader has no creases or rips. If necessary,
crimp the end of the tape with the tape crimper. Insert 8 cm to 10 cm (3 in to 4 in) of tape into the
thread block column. Close the transport front door. Follow the instructions and check for the events
specified in Figure 3-19.
3.5.1.6

Unload Sequence - Follow the instructions and check for the events specified in Figure 3-20.

3.5.1.7

Manual Load Repeatability - Perform the following steps.

Mount a 216 mm or 178 mm (8.5 in or 7 in) tape reel onto the supply hub.

3-22

PRESS RESET
BUnON.

!
PRESS UNLOAD
BUTTON.

!
AC MOTOR STOPS.
SUPPLY REEL TURNS
CCW. TAKE UP REEL
TURNS CWAND
THEN CCW.

~
TAPE UNLOADS AND
WRAPS ONTO SUPPLY
REEL.

J
SUPPLY REEL
STOPS.

j
CARTRIDGE MOTOR
CLOSES.

!
TAKE UP REEL STOPS
FILE PROTECT LAMP
COMES ON.
MA-2652

Figure 3-20

Unload Sequence

2. Check that the leader has no creases or rips. If necessary, crimp the end of the tape with the tape
crimper.
3. Insert 8 cm to 10 cm (3 in to 4 in) of tape into the threadblock column.
4. Close the transport front door.
5. Initiate a manual load by pressing and releasing the LOAD /REW button.
6. If the tape loads successfully, press the UNLOAD button to unload the tape.
7. Repeat steps 3, 4, 5, and 6 eight times. If a failure occurs within the 8 tests, continue manual
loading up to 20 tests. There should be no more than 3 failures among 20 successive tests.
After completing the manual load repeatability test, check the tape for damage caused by the tape
transport. The tape should not show damage sufficient to cause a load failure or data errors.

3-23

3.5.1.8

Autoload Repeatability - Perform the following steps.

Mount a 267 mm (10.5 in) tape reel onto the supply hub.

Check that the leader has no creases or rips. If necessary, crimp the end of the tape with the
tape crimper.

Close the transport door.

Initiate an autoload by pressing and releasing the LOAD /REW button.

If the tape loads successfully, press the UNLOAD button to unload the tape.

If autoload fails, the tape automatically tries to load a second time. If the second attempt
fails, the load fault lamp flashes. This is counted as one failure.

Repeat steps 4, 5, and 6 nine times. If a failure occurs within the 9 tests, continue autoloading up to 20 tests. There should be no more than 2 failures among the 20 successive tests.

After completing the autoload repeatability test, check the tape for damage caused by the
tape transport. The tape should not show damage sufficient to cause a load failure or data
errors.

3.5.2 Subsystem Quick Check
Perform this test using the TM78 formatter for each TU78 transport, one at a time.
1.

Load a write enabled scratch tape on the desired transport. Place th(~ transport on-line.

Place the transport port select switch in the number 3 position (maintenance mode).

Enable the TM78 maintenance keypad by pressing the ENA key. The display should respond
with HELLO.

Select the transport as follows.

•

Press 0 (parameter item #0).

•

Press PAR. (The display should flash parameter item 0, then display its contents.)

•

Enter the TU number to be exercised by pressing 0, 1, 2, or 3.

•

Press DEP. (The display should flash the new contents of pararneter item 0).

Issue a Write GCR command to the transport.
•

Enter 63. (The display should show 63).

•

Press EXE.

The subsystem executes the write GCR command, puts the results in the display, and waits
for the next command. The results are in the format II-FF, where II is the interrupt code and
FF is the failure code. The only two acceptable results are 01-00 (done with no errors), or
01-01 (done with a correctable error). Any other results are not acceptable, indicating a
problem somewhere in the subsystem. Refer to the interrupt code/failure code cross-reference and troubleshooting sections of the TM78 Technical Manual.

3-24

•

The write GCR command may be executed again by pressing EXE, or repeatedly by
pressing REP. To halt a repeated operation, press CLR.

Repeat the quick check (steps 1, 2, 4, and 5) for each transport in the subsystem.

Disable the keypad by pressing the ENA key. The display should go blank.

Turn both TM78 MASS BUS ports on-line, by flipping TM78 backplane DIP switches 1 and
5 to the left 1 position.

Verify each TU78 vacuum and pressure setting by performing the procedures in Paragraph
6.5.4 of the TU78 Technical Manual, Volume 2. This is especially important if a high altitude belt/pulley kit has just been installed. Adjust any setting that is out of tolerance.

3.5.3 TM78/TV78 System Level Diagnostics
Mount and load a write enabled 267 mm (10.5 in) tape reel. Place the transport on-line and check that
the on-line indicator lights. Set the transport port select switch to 0 or 1, depending upon the MASSBUS port being driven. If exercising a single port subsystem, set the switch to o.
Table 3-3 lists the TM78/TU78 diagnostics for DECsystem 10/20 and VAX-I 1/780 systems. Load
and run the appropriate diagnostics. Refer to the instructions in the diagnostic documentation and use
the parameters specified in the following paragraphs.
Table 3-3 TM78/TU78 Diagnostics for Acceptance Testing
Title

DECSYSTEM-20

VAX

Description

Control
Logic Test

DFTUI

EVMAE

Tests MASSBUS controller
and TM78 formatter logic.
Also tests subsystem basic
command functions while
checking for proper tape
motion timing. Must be run
from each CPU separately,
through both MASSBUS ports
(if dual port option
present). Provides error
information to user via
console or line printer.

Data
Reliability

DFTUJ

EVMAA

Tests TM78 circuitry and
TU78 circuitry by writing
and reading predetermined
data patterns and recording
modes. Provides error
information to user via
console or line printer.
May be run in dual port
mode (from dual CPUs)
driving two or more
transports.

3-25

3.5.3.1

DECsystem 10/20 Diagnostics

DFTUI (Basic/Control Logic Supervisor)
1.

Run one pass of test "accept" (TM78 acceptance) with all manual intervention tests enabled.
Allow one pass with no errors.

Run "accept" for five passes with manual intervention tests disabled.
Allow five passes with no errors.

DFTUJ (Data Reliability)
1.
3.5.3.2

Allow one pass in default mode with the error criteria listed in Table 3-4.
VAX 11/780 Diagnostics

Standalone Mode (Level 3)
1.

Control Logic Test (EVMAE) - Boot the diagnostic supervisor (ESSAA) and configure system (select drives, RHs, etc.) to run TM78/TU78.
Run the control logic test (EVMAE) for one pass with all manual intervention tests enabled.
After loading the diagnostic supervisor, in order to print the subtest header information, type
in SET TRACE.
Proceed as follows after the supervisor prompt.
DS>SET TRACE
DS>RUN EVMAE/SEC:MANUAL
Allow one pass with no errors.
Run the control logic test again for five passes without the manual intervention tests as follows.
DS>START/PASS:5
Allow five passes with no errors.

Data Reliability (EVMAA) - Run the data reliability exerciser (EVMAA) for one pass. A
pass comprises two complete tape passes (to EOT), once for PE format and once for GCR
format.
Proceed as follows after the supervisor prompt.
DS>RUN EVMAA
or in conversation mode
DS>ST /SEC:CONVER
Allow one pass with the error criteria in Table 3-4.
3-26

On-Line Mode Under VMS (level 2)
1.

Boot the VMS operating system and load the diagnostic supervisor (ESSAA). Run the data
reliability test (EVMAA) for one pass, preferably with other users Gobs) running simultaneously.
Allow one pass with the error criteria in Table 3-4. Make sure that the TU78 tape subsystem
does not degrade total system performance in the on-line mode.

Table 3-4

Maximum Error Rate Per Pass

Error Type
Status Errors
Non-recoverable
Media
Double track corrections
Single track corrections
Data compare
Others

Write

Read

Read Reverse

0
0

1
5

o
20

NOTES
One pass consists of writing and reading from BOT to EOT twice, once in each density mode.
If the TU78 does not meet these specifications, further passes are necessary to determine the validity of errors.

3-27

CHAPTER 4
CUSTOMER CARE
AND PREVENTIVE MAINTENANCE

4.1 CUSTOMER RESPONSIBILITIES
The following is a list of maintenance procedure for which the customer is responsible.
1.

Obtain operating supplies, including magnetic tape and cleaning supplies.

Supply accessories, including cabinetry, tables, and chairs.

Maintain the required logs and report files consistently and accurately.

Make the necessary documentation available in a location convenient to the system.

Keep the exterior of the system and the surrounding area clean.

Make sure that ac plugs are securely plugged in each time equipment is used.

Perform specific equipment care operations described in Paragraph 4.2 and 4.3 at the suggested frequencies, or more often if usage and environment warrant.

4.2 MAGNETIC TAPE CARE
The following is a list of steps necessary for properly maintaining magnetic tape.
1.

Do not expose magnetic tape to excessive heat or dust. Most tape read errors are caused by
dust or dirt on the read head; it is imperative that the tape be kept clean.

Always store tape reels inside containers when they are not in use. Keep the empty containers
tightly closed to keep out dust and dirt.

Never touch the portion of tape between the BOT and EaT markers. Oil from fingers attracts dust and dirt.

Never use a contaminated reel of tape. This spreads dirt to clean tape reels and could have an
adverse affect on tape transport reliability.

Always handle tape reels by the hub hole. Squeezing the reel flanges could lead to tape edge
damage in winding or unwinding tapes.

Do not smoke near the tape transport or storage area. Tobacco smoke and ash are especially
damaging to tapes.

4-1

4.3

Do not place magnetic tape near any line printer or other device that produces paper dust.

Do not place magnetic tape in any location where it might be affected by hot air.

Do not store magnetic tape in the vicinity of electric motors.

PREVENTIVE MAINTENANCE

4.3.1 General
Digital Equipment Corporation tape transports are highly reliable precision instruments that provide
years of trouble-free performance when properly maintained. A planned program of routine inspection
and maintenance is essential for optimum performance and reliability. The following information assists
the customer in caring for his equipment and maintaining the highest level of performance and reliability.
4.3.2 Preventive Maintenance
To ensure trouble-free operation, a preventive maintenance schedule should be kept. This involves
cleaning only a few items, but the cleanliness of these items is very important to proper tape transport
operation. The frequency of the cleaning varies with the environment and degree of use of the transport.
Therefore, it is difficult to define a general schedule for all machines. Daily cleaning is recommended
for TU78 units in constant operation in ordinary environments. This schedule should be modified if
experience shows other periods are more suitable. Paragraph 4.3.4 contains the cl(~aning instructions.
Before performing any cleaning operation, remove the file reel and store it properly. All items in the
tape path should be cleaned on a daily basis. It is important to be thorough yet gentle and to avoid
certain dangerous practices. Some tape cleaners are strong cleaning agents and should not come in contact with painted surfaces or plastic.
CAUTION
Do not use acetone or lacquer thinner, rubbing alcohol, or excessive cleaner. Be extremely careful not
to allow the cleaner to penetrate ball bearings and
motors.
4.3.3 Magnetic Tape Transport Cleaning Kit
A magnetic tape transport cleaning kit (TUCOl) has been provided. Its materials do not harm tape
equipment and do not leave any residue behind to interfere with data reliability. The following paragraphs contain hints to make sure that the very best results are obtained.
The Freon TFl13™ cleaning fluid in this kit is one of the safest and best degreasing agents available.
It does not adversely affect any part of DIGITAL's tape equipment. To ready the can, unscrew the top
and punch a small hole in the metal seal covering the pour spout.
WARNING
TF113 is a non-restricted, non-hazardous substance.
However, avoid excessive skin contact. Do not allow
it to come in contact with the eyes, and do not swallow it. Use only in a well-ventilated area.

TMTrademark of Dow Chemical Company

4-2

Never dip a contaminated cleaning swab or wipe into the can. To transfer fluid onto the swab, pour a
little into the cap and dip the swab into the cap. Discard the fluid remaining in the cap when the cleaning operation is complete.
Always keep the can tightly closed when not in use because the fluid evaporates rapidly when exposed
to air.
Use the cleaning materials contained in the kit to clean tape heads, air bearings, tape guide blocks, the
tape cleaner, capstan, reel hubs, and any part of the transport where a dirty residue might contact the
tape. To clean other parts of the transport (such as the exterior surfaces of doors) use any reasonably
clean, lint-free material, with or without cleaning fluid.
NOTE
For an unusually stubborn dirt deposit that appears
to resist TFl13, try a mild soap and water solution
to dislodge it. After using soap, be sure to wash
down the affected area thoroughly with TFl13 to remove soapy residues.
4.3.4 TU78 Tape Transport
Perform the following steps to clean the TU78 tape transport.
1.

Dismount the tape from the unit.

Clean the following components of the transport using a foam-tipped swab soaked in cleaning
fluid (Figure 4-1).
Read/write head
Erase head
Tape cleaner
Air bearings (6)
Spring-loaded ceramic tape guides (2)
Thread blocks (6)
Capstan
Buffer boxes (2)
Pucker pocket
Buffer box glass, pocket glass, door overlay
NOTE
Only use the foam-tipped swabs. Do not touch any
part of the tape path since oil from fingers attracts
dust and dirt. Also, excessive physical pressure on
the capstan could affect its alignment.

When cleaning the thread blocks, be sure to clean the air guide ports. Every thread block has
air guide ports except the metal block containing the spring-loaded tape guide.

When cleaning the spring-loaded ceramic guides, be sure that the washer is pressed firmly
against the tape guide surface and not hung up on its shaft.

When cleaning the inner surface of the vacuum door, use a lint-free wipe and cleaning fluid.
Pass another lint-free wipe over the head using a polishing actIon to remove any remaining
deposits.

4-3

AIR BEARING
NO.2
AIR BEARING
NO.3
THREAD BLOCK

AIR BEARING
NO.4
-r~~------~----~~~

AIR BEARING
NO.5 AND
SPRI NG LOADE D
TAPE GUIDE

-mru:==:~~;;;::::;;;~dJ~

TH READ ~:f=~~==--.,L.Jjt
BLOCKS ""

AIR BEARING NO.6

SPRING LOADED
TAPE GUIDE

VACUUM
CAPSTAN
MA-2637

a. Tape Path I terns

BUFFER

BOX GlASS,,{

POCKET
GLASS

Mk263B

b. Buffer Box Door
Figure 4-1

Transport Items for Daily Cleaning

4-4

4.4 ORDERING SUPPLIES, ACCESSORIES AND DOCUMENTATION
For infornlation about supplies, accessories, and additional documentation for your TU78 tape transport (or for any DIGITAL equipment), contact your local sales office or call DIGITAL Direct Catalog
Sales.
Continental US, 8:30 am to 6 pm (EST), call 800-258-1710
New Hampshire, 8:30 am to 6 pm (EST), call 603-884-6660
Chicago, 8:15 am to 6 pm (CT), call 312-640-5612
San Francisco, Alaska, and Hawaii, 8: 15 am to 6 pm (PT),
call 408-734-4915.
Terms and conditions include net 30 days and F.O.B. DIGITAL plant. Freight charges are prepaid by
DIGITAL and added to the invoice. Minimum order is $100.00. (Minimum does not apply when full
payment is submitted with an order). Checks and money orders should be made out to Digital Equipment Corporation.
Purchase orders for supplies, accessories, and documentation should be sent to the following address.
Digital Equipment Corporation
Accessories and Supplies Group
P.O. Box CS2008
Nashua, New Hampshire 03061
Purchase orders must show shipping and billing addresses and state whether a partial shipment will be
accepted.
In addition to the hardware documentation listed in Table 1-1, the following accessories and supplies
may be purchased to support the TU78 tape transport.
Item

Part No

Description

Magnetic Tape

TUM24-A

732 M (2400 ft) magnetic tape in
autoload belt

Magnetic Tape

TUM24-AL

10 TUM24-A tapes

Magnetic Tape

TUM24-AM

50 TUM24-A tapes

Autoload Belts

TUM24-AX

10 autoload belts for 26.7 cm
(l0.5 in) diameter tape reels

Cleaning Kit

TUCOI

Magnetic tape transport cleaning
kit containing fluid, swabs,
wipes, and cleaning instructions

Markers

90-09177-00

Magnetic tape foil sensing
markers for re-creating EOT /BOT
points

4-5

APPENDIX A

GLOSSARY

ACRC

Auxiliary cyclic redundancy check

AMTIE

Amplitude track in error

ANSI

American National Standards Institute

BOT

Beginning of tape

CPU

Central processor unit

CRC

Cyclic redundancy check

DIP

Dual in-line package

ECC

Error correcting code

EOT

End of tape

FCPI

Flux changes per inch

GCR

Grou p code recording

IRWU

Interface rewind unload

MIA

Multiple interface adaptor

PCB

Printed circuit board

Phase-encoded

REW

Rewind

TIP

Tape in path

TUBUS

Tape unit bus

WLO

Write lockout

A-I