Digital Equipment TU55 User manual

H-TU55
~--. -
INSTRUCTION MANUAL
DECTAPE TRANSPORT
" -.... -_.
DIGITAL EQUIPMENT CORPORATION • MAYNARD, MASs4cHUS~TTS
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DECTAPE TRANSPORT
TU55
INSTRUCTION MANUAL
H-TU55
DIGITAL EQUIPMENT CORPORATION • MAYNARD, MASSACHUSETTS

This manual contains proprietary information. It is provided to the
customers of Digital Equipment Corporation to help them properly
use and maintain DEC equipment. Reveal ing the contents to any
person or organization for any other purpose is prohibited.
Copyright 1966 by Digital Equipment Corpora:tion
ii

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1.2
1.3
1 .3.1
1 .3.2
1 .3.3
1.4
loS
1.S.1
1.6
2
2. 1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.S
2.2.6
2.2.7
2.2.8
2.2.9
2.2.10
2.2.11
2.3
2.3.1
2.3.2
2.3.3
DECTAPE TRANSPORT TUSS
CO NTE NTS
INTRODUCTION AND DESCRIPTION ...........•..•..........•.........
General Description ..•.••.•.•••..••..•....••••.••.•.••....••.•••..
Scope of Manua I .••••..••••.•.•••••••••.•••.•....••....•...•..•.••
Pertinent Documents ......•..................•.•......•.•.•...••...
Manuals ..........•...................•.•.•.....•...•..••.•..
Engineering Drawings .........••..........•..•........•.......•
New Module News Bulletins ...................••...•.•.....•...
Functional Description .....•.•...•.••..•.•..•..•...•.•..•..•...•...
Phys ica I Descri ption .......•............•...•..•.....•..•••.•.•....
Electrical Details ............••.••.•.............•....•.••....
TUSS Performance Characteristics ....••..•..........•.....•.....••...
THEORY OF OPERATION .......•..................•...........•.......
Block Diagram Analysis •.•..............•.....•..•••..•.•.•..•..•..
Detailed Descriptions .....•••..•.........•..•.••..•.••............•
Interface .............. : ........•..•............•.....•.......
Unit Select Lines ...........•....•....•.........•........•.••.•
Command Lines ..•..•....•.....•..•..•........ ~ .......•..•....
WRITE ENABLE Signal
Interface Connections
Read/Write Head ..................•........••...•.••.....•••..
Tape Motion Control ..........••.•..•.•........••.•..•••..•..•.
Remote or" Programmed Control •..•..••.••••.••.•...•.•...•.••••.
Local (Manual) Control ....•.........•.•.•..•.•••...••.•....••.
Motor Control ......•.....•........•..••........••..•.....••..
Transport Selected Signal .............••..•............•....••.•
Module Descriptions ..........................•.•........•.•.......
Type R303 Integrating One Shot (Delay) .......•....•..•..........
Type WS13 Level Amplifier ..................•.......•..........
Type G8S0 SCR Motor Driver ..................•........•.......
iii
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3
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3.3
4
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4.6
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5
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5.3.1
5.3.2
5.4
Figure
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1-5
DECTAPE TRANSPORT TU55
CON TEN TS (Continued)
OPERATION .•••.•..••..•••••...•.•••.•.••••.••.•..•... ' ..•..•........
Introduction ....•.•...•...••.•....................•. ' ..........•...
Controls and Indicators ...•..........•....••......•........•........
Operating Notes ....•.•....•..••.•.•....•..••...•..•••..•.....
Loading Tape ........•.......••.•.•.•........•.•..•.......•..•...•
MAINTENANCE •..•....•..•.........••...••.............•.•......••..
Equipment Required •.•.•..••...•..•..••••.•..•...•.•.• ',' ••..••••..•
Preventive Maintenance •••••••.•.••..•..•.•.•......•..•..•.•..•....
Weekly Schedule ...•.•...•••......•.....•.•...••..•..•.•...•..
Monthly Schedule ..•.••.••••.••.•..••...••...•................
Tape Tension and Transport Stop Ad justment .•••.•.•.•.•.•.•.•..•..•.•.
Head Output Check ..•..•••••.••.•...•.••..•.••••.••.•..••.••••.•.
Head-Skew Check ..•.•••..••••.••••....•.••..•.••••••••.•.•.•..••.
WRITE ENABLE Circuit Check .••••••..•.••..••.•.••.••...••.••••..••
Troubl eshooti ng ••.••.•..•••••••.•...•.••.•...•.••••...•...•.•..•..
Recommended Spares ..•.••••••••••.•..•.•••••••••.•.•.•..•••..•••••
ENGINEERING DRAWINGS ••.•••••.••••••.•..••••..•.••••.••••..•••••.
Introduction .•••••••••••••••••••.•••..••••••••.••.•.••...••••••.••
Circuit Symbols ......•.•........•.•......•....••..•.•.••..••••.•••
Logic Signal Symbols ..•.•.••.••.••.•..••.•••.•.•..•....•........•.
Logic Levels .•..•..•..•.•..••••.•....•••....•......•..••......
FLIP CH IP Pulses .•..••••••..•••..••••••••.•••••••.•....•••....
Semiconductor Substitution .........................................
ILLUSTRATIONS
Type TU55 DECtape Transport ••.•.•.••••..•...•••.•..••...•.••..•..•.•..
Hub and Reel Assembly ......................•..........................
Arrangement of DEC tape Head .••••.••...•••....•...•....•.•.••..••.....
Type TU55 DECtape TransportI Rear View .•••••..•.•••.•••...•.......•.••.
TU55 Interface Connections .•....•••.•••••.•••..••.••••.•••••••.•.•.••••
iv
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Table
1-1
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5-1
Drawing
DECTAPE TRANSPORT TU55
CON TEN TS (Continued)
DECrape Transport TU55 Block Diagram
•.••.•••••••.••••.••••••••.••.•.•••
Head Connections •••••••.•.•.•••••••••••.••••.••••••.•••••••.•••.•••.•
Symbol ized Schematic of G850 SCR Motor Driver •••••••••••••••••••••••.••
Modu Ie Ad justment Tri mpots .•••••••••..••..•..•..••••••••....••.•...•..
DEC Symbols ...•..........••..•....•....•.•..••.••....•.•....•.......
FLIP CH IP R-Series Pulse .•.•.....•.••.•••..•....•.........•.•....•.....
FLIP CHIP B-Series Pulse •.....•.....•....•.••.•.•.•.•........••.•..•.•.
TABLES
Summary of Equipment Characteristics for the TU55 DECtape Transport ..••....
Motor and Brake Operation Truth Table ..•...••.....•........•.••.•.•..•..
Functions of Controls and Indicators .•.•••••.•...•..•........•.•......••.•
Recommended Maintenance Equipment .....•.••.......•..•..•.............
Recommended Spare Parts •••••.•••••••••••••••••.•.•..•.••.••.•.•••..••
Semiconductor Substitution ••••.••••••••••••••••••.•••••••.••••.•.••••••
ENGINEERING DRAWINGS
BS-D- TU55-0-2
MU- D- TU55-0-5
WD-D- TU55-0-4
WL-A- TU55-0-3
CP-A- TU55-0-6
RS-B-G850
RS-B-G851
RS-B-R002
RS-B-R107
RS-B-Rll1
RS-B-R202
So Iid State DECtape Transport ••••••••.•••.••••.••••••••.•.••
Module Utilization List •••••.••••.••••••••.••.••...•..•....•
Bus Bar for TU55 •••••••.••••••.••.••••.••••.••••.••...•••••
TU55 Transport Wiring List ••••••••••••••••••••••••..•••••.•••
Components List •••.•••••••••••.••••••••••••••••.....•.••••
SCR Motor Driver ••..•••.••.••••••••••••••.••••.•••••••••••
Re Iay ••••.•••••••.•••••..•••.••••••.•••••••••••..••..••••
Diode Cluster ••••••••••••••.•••••••••••••••••••••••••••.•••
Inverter ••••••••••.•••••••.••••.•••••••..•••.••••.••...•••
Diode Gate •••..••••••••.••••.••.•.•••••••.••••.•••..•••••
Dual FI ip-Flop •••••.•••.•••.••..•••..•••..••••.••••.•.••.••
v
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Drawing
RS-B-R303
RS-B-W023
RS-B-W032
RS-B-W040
DEer APE TRANSPORT TU55
CO t\l TEN TS (Continued)
Page
Integrating One-Shot •.....•..•.••.....•....................•...• 5-16
Ind icator Ampl ifiers
5-16
DECtape Signal Connector •••....•...•..••••...•.........•...•.. 5-17
Solenoid Driver...... • . • • . . . . . . . . • • . . . • • . . . . • . . . • . . . . • . . • . . . . . • 5-17
VI

DECT APE TRANSPORT TU55
CHAPTER 1
INTRODUCTION AND DESCRIPTION
1.1 GENERAL DESCRIPTION
The Type TU55 DECtape Transport (see figure 1-1) is a sol id-state, bidirectional, magnetic-
tape handl ing device designed and manufactured by the Digital Equipment Corporation (DEC) for use in
DEC digital computer systems. When used witha suitable DECtape control system, the TU55 provides a
fixed-address magnetic-tope facility for high-speed loading, readout, and program updating. The DEC-
tape control system directs the transport to read forward or in reverse, to write forward or in reverse, to
stop, and to go. The TU55 contains tape handling elements, drive mechanisms, and solid-state switching
circuits which switch the tape head onto a master bus system and interpret command instructions from the
control un it. The highly rei iable sol id-state switching circuits in the TU55 are completely compatible
with the older Type 555 DECtape Transport (which uses relay switching) and may be used to modify and
expand systems employing the older type transport.
Figure 1-1 Type TU55 DECtape Transport
1-1

DECT APE TRANSPORT TU55
1.2 SCOPE OF MANUAL
This instruction manual is intended to aid personnel in the maintenance of the TU55 DECtape
Transport. The equipment is discussed primarily from a maintenance point of view, but some information
is given on the operation of its associated controls and indicators. Pertinent documents I isted in the fol-
lowing subsection contain more complete information on operation from a F>rogrammer's viewpoint.
Since the transport is one element of a computer/control/transport system, the reader is in-
vited to fam il iarize himself with the internal operations of both computer cmd control. Of spec ial
importance are the sections concerning program interrupts, programmed in/out transfers, and the data-
break facility in the computer; and the select and motion control logic in the external DECtape control.
Detailed descriptions of the tape format, instruction repertoire, and progn::lmming practice for using the
TU55 with a particular computer can be found in the user handbook for th~~ computer. Control informa-
tion for the TU55 can be obtained from the maintenance manual for the DECtape control system used
with the transport.
1 .3 PERTINENT DOCUMENTS
The following documents provide source information relative to the use of the DECtape Trans-
port Type TU55:
1 .3. 1
1 .3.2
Manuals
Digital FLIP CH IP Modu les Catalog, C-105
PDP-7 User Handbook, F-75
PDP-8 User Handbook, F-85
DECtape Control 550 Instruction Manual, H-550
DECtape Control 551 Instruct ion Manual, H-551
DECtape Control 552 Instruction Manual, H-552
DECtape Control TCOl Instruction Manual, H- TC01
DECtape PDP-8 Programming Manual, Digital-8-27-U
Engineering Drawings
A
set of reduced' engineering drawings for the TU55 is contained in chapter 5. These drawings
are in addition to the complete set of full-size drawings forwarded with eClch TU55. As explained in
chapter 5 all maintenance personnel should use only the full size engineering drawings for work on the
equ'ipment because these drawings show v(Jriations pecul iar to an individuol installation.
1-2

DECT APE TRAI'lSPORT TU55
1.3.3 New Module News Bulletins
G850 SCR Motor Driver
G8S1 Relay
W513 Level Ampl ifier
In addition to the above documents, complete sets of Library Programs are available for each
computer using DECtape systems.
1
.4 FUNCTIONAL DESCRIPTION
The TU55 Transport provides a read/write head for recording and playback of information on
five channels of the O.75-inch tape. Each channel consists of two nonadiace~t coils which are wired
in series. Thus, information on one track combines with redundant information on another to create a
single signal. Connections from the read/write head are made directly to the external control unit which
contains the read and write amplifiers as well as the command logic for the selection and remote control
of tape motion.
The left hal f of the front panel (see figure 1-1) contains the tape deck with reels and reel
motors, tape guides, and the read/write head; the right half is the local control panel with rocker
switches for selection and manual operation. The 600-rpm induction motors that drive the reel hubs
directly control tape motion. No capstans, pinch rollers, or drag pads contact the tape.
The logic circuits of the TU55 command tape movement in either direction over the read/write
heads. Soliq-state switching circuits completely control the tape drive motors. These circuits govern
the torque applied to each reel motor to transport the tape across the head in accordance with specific
commands (i .e., go, forward, reverse, stop).
In normal tape movement, full torque is appl ied to the take-up reel, thus establ ishing the
direction of motion. Reduced torque, applied to the trailing reel, maintains proper tape tension. Tape
motion is bidirectional so that either reel can serve as the take-up reel. The DECtape system uses the
so-called Manchester phase recording technique rather than an amplitude sensing technique; thus, tape
speed need not be a prec isely controlled parameter. Actua"y, the speed varies ±20%, depending upon
the diameter of the tape pack on the take-up reel. An electromagnetic brake mounted on each motor
shaft achieves a positive stop by braking the trailing reel at the end of a motion command. The take-up
reel motor continues to apply partial torque to take up tape slack. Whenever the tape is motionless,
one of the two reel brakes is appl ied opposite to the direction of the last tape movement.
1-3