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EK-0TU78-PS-1

May 1981

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Document:	TU78 Subsystem Pocket Service Guide
Order Number:	EK-0TU78-PS
Revision:	1
Pages:	63
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OCR Text

E K-OTU78-PS-OO1

rU78
.Subsystem
Pocket
Service
Guide

. ~DmDDmD

EK-OTU78-PS-001

TU78

Subsystem

Pocket
Service
Guide

digital equipment corporation. maynard, massachusetts

1st Edition, May 1981

Copyright © 1981
by Digital Equipment Corporation.
All Rights Reserved.
The reproduction of this material, in part or
whole, is strictly prohibited. For copy information, contact the Educational Services
Department, Digital Equipment Corporation,
Maynard, Massachusetts 01754
0

The information in this document is subject
to change without notice. Digital Equipment
Corporation assumes no responsibility for
any errors that may appear in this document.

Printed in U.S.A.

The following are trademarks of Digital
Equipment Corporation~ Maynard, Massachusetts.
DEC
DEC net
DECUS
DECsystem-l0
DIGITAL
DECSYSTEM-20
Digital Logo DECwriter
PDP
DIBOL
UNIBUS
EduSystem
lAS
VAX
MASSBUS

OMNIBUS
OS/8
PDT
RSTS
RSX
VMS
VT

CONTENTS
1

INTRODUCTION

1.1
1.2
1.3
1.4
1.5
1.6
1.6.1
1.6.2
1.7
1.8
1.8.1
1.8.2
1.9
1.9.1
1.9.2
1.1 0
1.11

General. . . . . . . . . . . . . . . . . . . . ..
Subsystem Overview . . . . . . . . . . . ..
TM78 Assemblies . . . . . . . . . . . . . . ,
TV78 Assemblies . . . . . . . . . . . . . . ,
Operator Controls and Indicators. . . ..
Maintenance Controls and Indicators ..
TM78 Controls and Indicators. . . ..
TV78 Controls and Indicators .... ,
Tools . . . . . . . . . . . . . . . . . . . . . ..
Spares Kit Lists . . . . . . . . . . . . . . . .
TM78 Spares Kit . . . . . . . . . . . . .
TV78 Spares Kit . . . . . . . . . . . . . ,
Recommended Spares Levels (RSL) .. ,
Additional TM78 RSL Parts. . . . ..
Additional TV78 RSL Parts .. . . ..
Related Documents. . . . . . . . . . . . ..
System Diagnostics . . . . . . . . . . . . . ,

1
1
1
1
1
11
12
12
12
16
16
17
18
18
18
21
23

TROUBLESHOOTING

2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
2.8

Introduction . . . . . . . . . . . . . . . . . ,
On-Line Diagnostics . . . . . . . . . . . . .
In-Line Diagnostics. . . . . . . . . . . . ..
Error Logs. . . . . . . . . . . . . . . . . . ..
Status Indicators for Troubleshooting..
Error Codes . . . . . . . . . . . . . . . . . . ,
TM78 Maintenance Panel . . . . . . . . . ,
Keypad Function Summary ......
Errors. . . . . . . . . . . . . . . . . . . ..
Parameters. . . . . . . . . . . . . . . ..
Maintenance Instructions . . . . . . ..
Sample Maintenance Routine .. , .,
Test Points . . . . . . . . . . . . . . . . . . .

24
24
24
24
24
25
42
42
45
46
55
58
58

iii

APPENDICES

CONTENTS

CHECKS AND ADJUSTMENTS

3.1
3.2

ESB #57 (TUX)

Parts Replacement . . . . . . . . . . . . . . 63
Quick Reference Adjustment
Specification . . . . . . . . . . . . . . . . .. 63

APPENDIX A

SUBSYSTEM MASSBUS
REGISTERS

APPENDIX B

EXTENDED SENSE BYTES

FIGURES
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
2-1
2-2
3-1
3-2
3-3
3-4
A-I
A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-IO
A-II
A-12
A-13
A-14
A-15
A-16

111

Dual-Ported TV78 Subsystem . . . . . ..
TM78 Front View. . . . . . . . . . . . . ..
TM78 Module Layout (Back View)
Showing Maintenance Indicators . . . .,
TV78 Assemblies (Front View) . . . . ..
TV78 Assemblies (Back View) . . . . . .
TV78 Card Cage Showing
Maintenance Controls and Indicators ..
TV78 Operator Control Panel . . . . . ..
H7422 Power Supply Showing
Maintenance Indicators and Controls ..
Door Safety Interlock Switch . . . . . ..
TM78 Maintenance Panel . . . . . . . . . ,
Sample Write/Read Routine . . . . . . ..
TV78 Card Cage Showing
Maintenance Switches and Adjustment.
GCR/PE Preamp 1 PCBA Test Points ..
Interconnect F 1 PCBA . . . . . . . . . . .
Vacuum Valve and Pressure Valve ....
RH20 and RH780 Addresses. . . . . . ..
Control and Status Register . . . . . . . .
Data Transfer Interrupt Register . . . ..
Tape Control Register . . . . . . . . . . ..
Drive Type Register . . . . . . . . . . . . .
Tape Vnit Status Register. . . . . . . . ..
Motion Interrupt Code Register. . . . ..
Motion Command Register . . . . . . . ..
Hard ware Control Register . . . . . . . .,
Configuration/Status Register . . . . . . ,
Control Register . . . . . . . . . . . . . . .,
Status Register . . . . . . . . . . . . . . . . ,
Virtual Address Register . . . . . . . . . .
Byte Counter Register . . . . . . . . . . ..
Diagnostic Register . . . . . . . . . . . . .,
Map Register . . . . . . . . . . . . . . . . ..

2
3

LAST
RECORD
SEEN
WAS A

TAPE WAS
TU EXISTS
DATA
LAST
AND POWER SECURITY
MOVED
IS ON
ERASE IN
IN REVERSE
PROGRESS

TAPE MARK

NON-DATA REWIND IN
TRANSFER PROGRESS
COMMAND
ISSUED FROM
A MASSBUS
PORT IS
!N PROGRESS.

0= LAST MASSBUS
COMMAND CAME
FROM PORT A
1= LAST MASSBUS
COMMAND CAME
FROM PORT B

4
6
7

LAST TAPE
OPERATION
INVOLVED A
WRITE TO TAPE
MA-7967

8
9
13
14
43
59
73
74
75
77
80
81
83
84
85
86
87
88
91
92
93
94
95
95
96
97

Figure B-17

TU Software Status

ESB #58 (XFRCTL)

READ CHANNEL
PHASE LOCK
OSCILLATOR
BYPASS

WRITE CLOCK SELECT
0= NORMAL WRITE CLOCK
1= +20% CLOCK
2=+10% CLOCK (GCR READ)
3=-20% CLOCK (PE READ)
4= EXTERNAL CLOCK
5= SINGLE STEP
6/7= NOT USED
READ CLOCK SELECT
0= -10% CLOCK
1= +10% CLOCK
2= NORMAL CLOCK
3 = -30% CLOCK
4= EXTERNAL CLOCK
5= SINGLE STEP
6/7= NOT USED
MA-7968

Figure B-18

Transfer Control Byte

110

CONTENTS

APPENDICES

ESB #54 (TUDIAG)

ENABLE

NOT WRITING

0/1= 10% IBG CHECK
2= 25% WRITE
3= 20% READ

EOT
DETECTED
MA-7965

Figure B-15

MIA TV Diagnostics Byte

B-1
B-2
B-3
B-4
B-5
B-6
B-7
B-8
B-9
B-I0
B-ll
B-12
B-13
B-14
B-15
B-16
B-17
B-18

ESB #56 (RETCNT+1)

Read Path Status Byte . . . . . . . . . . .. 98
Read Microcontroller Command Byte . . 100
Parity Read Channel Status Byte . . . . . 101
ECC Status Byte. . . . . . . . . . . . . . . . 102
Channel (N) Track in Error Byte ..... 103
TV Port Status Byte . . . . . . . . . . . . . 104
CAS Port (N) Status Byte . . . . . . . . . . 105
MASSBVS C Bus Status Byte ., . . . . . 105
MASSBVS D Bus Status Byte ....... 106
Write Microcontroller Error Byte . . . . . 106
Interrupt Status Byte . . . . . . . . . . . . 107
TV78 Status Byte . . . . . . . . . . . . . . . 107
MIA Status A Byte . . . . . . . . . . . . . . 109
MIA Status B Byte . . . . . . . . . . . . . . 109
MIA TV Diagnostics Byte. . . . . . . . . . 110
Retry Control Byte . . . . . . . . . . . . . . 110
TV Software Status. . . . . . . . . . . . . . 111
Transfer Control Byte . . . . . . . . . . . . III
TV78 Subsystem Detailed
Block Diagram . . . . . . . . . . . . . . . . . 112
Write Path Troubleshooting Diagram .. 113
Read Path Troubleshooting Diagram .. 113

TABLES
LAST RETRY
INITIAL
WAS IN THE COMMAND
OPPOSITE MOVED TAPE
DIRECTION OF REVERSE
INITIAL
COMMAND
INITIAL
COMMAND
WASA READ
MA-7966

Figure B-16

Retry Control Byte

1-1
1-2
1-3
2-1
2-2
2-3
2-4
2-5
2-6
2-7
3-1
3-2
3-3
A-I
A-2
B-1
B-2

TV78 Controls . . . . . . . . . . . . . . . .. 10
TV78 Indicators . . . . . . . . . . . . . . .. 11
TV78 Maintenance Controls . . . . . . ., 16
TM78/TV78 Diagnostics . . . . . . . . . . 25
In-Line Self-Test Microdiagnostics . . .. 26
Troubleshooting Indicator Functions .. 27
Interrupt Code to Failure Code. . . . .. 29
Keypad Error/Status Codes ........ 45
Parameter Items . . . . . . . . . . . . . . .. 46
Maintenance Instruction Codes . . . . .. 55
Checks/Adjustments When Replacing
Parts . . . . . . . . . . . . . . . . . . . . . . . 63
Adjustment Specifications . . . . . . . .. 66
Vacuum and Pressure Valve
Components . . . . . . . . . . . . . . . . . . 78
Data Transfer Function Codes. . . . . .. 82
Nondata Transfer Function Codes. . .. 89
Read Microcontroller Status Codes .. , 99
Read Microcontroller Command
Codes . . . . . . . . . . . . . . . . . . . . . . . 101

APPENDICES

109

ESB #50 (MIA STAT A)

MIA IS IN
MANUAL
TEST MODE

TU
REVERSE

TU
FORWARD

WRITE
HEAD
INHIBIT

WRITE
COMMAND

TU
CAPSTAN
MOTION
DATA SECURITY
ERASE

LOOP
WRITE-TO-READ
TEST COMMAND

MA·7963

Figure B-13

MIA Status A Byte

ESB #51 {MIA STAT Bl

TU BUS
COMMAND
PARITY
ERROR

AUTOMATIC
READ
AMPLIFICATION
BURST ERROR

0= GCR MODE
1= PE MODE

PORT SELECT
SWITCH POSITION
6= POSITION 0
5= POSITION 1
3= POSITION 2
7= POSITION 3
MA-7964

Figure B-14

MIA Status B Byte

108

APPENDICES

Byte

Description

MIA register 1; MIA status A (Refer to Figure
B-13)

MIA register 2; MIA status B (Refer to Figure
B-14)

MIA register 3; serial NR A

MIA register 4; serial NR B

MIA register 5; diag (Refer to Figure B-15)

Retry counter (RETCNT) - This byte is the
count of retry interrupt requests given for the
tape unit. When this count is zero, the tape unit
is not in a retry sequence.

Retry control bits (RETCNT + 1) - This byte
is used by the microcode to control error
recovery. It is meaningful only when the retry
counter (byte 55) is not zero. (Refer to Figure
B-16)

TU software status (TUx). This byte contains
information about the tape drive. (Refer to
Figure B-17)

Transfer control word (XFRCTL) - This byte
contains control information used by data
transfer commands. (Refer to Figure B-18)

Retry suppress and format control (XRETRY).
This byte contains the contents of the left half
of the MASSBUS register, which contains the
retry suppress bit, format, and skip count.

Keypad enable flag (ENAON) - This byte is
not zero when the keypad is enabled.

INTRODUCTION

1.1 GENERAL
This document is designed for use by a person trained
to service a TU78 subsystem. A TU78 subsystem is
made up of a MASSBUS controller (RHXX), a TM78
formatter, and a TU78 tape transport. Procedures are
short, and support a maintenance philosophy of module
replacement.
This chapter presents an overview of the formatter and
transport for quick review. Chapter 2 is troubleshooting
information. Use of error logs, diagnostics, and maintenance panel features allow rapid location of malfunctions. Chapter 3 lists all adjustments in quick reference
format.
Programming information is not provided but register
summaries for each hardware family type are found in
Appendix A~ Appendix B lists the extended sense registers available in the diagnostic and error log printouts.
1.2 SUBSYSTEM OVERVIEW
The TU78 subsystem is shown in Figure 1-1. The example shown is a dual-ported TM78 formatter, controlling four TU78 transports. A detailed block diagram
of the subsystem may be found on the foldout at the end
of this book.
1.3 TM78 ASSEMBLIES
Major TM78 assemblies are shown in Figures 1-2 and
1-3.
1.4 TU78 ASSEMBLIES
Major TU78 assemblies are shown in Figures 1-4, 1-5,
and 1-6.
1.5 OPERATOR CONTROLS AND INDICATORS
All operator controls and indicators are on the TU78
control panel. Figure 1-7 shows the panel, Table 1-1 lists
the controls and their functions, and Table 1-2 lists the
indicators and their functions.

APPENDICES

I NTROD UCTION

MASSBUS
PORT SELECT
O=PORT A
l=PORT B

POWER OK

TRANSLATOR
(M8959)
ROM PARITY
ERROR

MASSBUS
PORT A
LOGIC NOT
PRESENT

TRANSLATOR
VPE ON
PE WRITE

PE WRITE
DONE
MICROCOMPUTE R
(M8960) ROM
PARITY ERROR

107

MASSBUS
PORT B LOGIC
NOT PRESENT
MA-7961

Figure B-11

Interrupt Status Byte

ESB #49 (TUST A T)
a:
w

I-

co2
r-.a:
20
I-u.

...J

«
z

i=
c...
0

~
""'
>.

""'

.l:)

TU IS ON
LINE AND
READY

rr.J

E-<

TU IS
ON-LINE
BUT NOT
NESSARILY
READY

BEGINNING
FILE
OF TAPE
PROTECTED
O=GCR MODE END OF
l=PE MODE
TAPE

"'0

READY WENT
TU IS
SET SINCE REWINDING
LAST TU CLEAR
COMMAND

I-

P;~

MA-7962

w
C/lU

:::)~
w
~I-

ala:
C/l

2~al

-e

Figure B-12

TU78 Status Byte

='
00

ti:

Byte

Description

Hardware register 340; interrupt status (Refer
to Figure B-ll)

MIA register 0; TU78 status (Refer to Figure
B-12)

106

APPENDICES

INTRODUCTION

ESB #34 (OBUS ST A)

PORT WRITE
ENABLED

MASSBUS
OCCUPIED

MASSBUS
EXCEPTION

WMC SCLK
OR
HARDWARE
REGISTER
300-1JIJ BIT 0

ON/OFF LINE
AD
}
Al
A2
ON/OFF LINE
AD

MASS'US PORT A {

MASS' US PORT, {

MASSBUS
END OF
BLOCK

MASSBUS
WRITE
CLOCK

MASSBUS
SYNC
CLOCK

MASSBUS
RUN

}

MA-7959

DRIVE SELECT/
ON-OFF
LINE SWITCHES

MASSBUS D Bus Status Byte

Figure B-9

MAINTENANCE
PANE L
-~~~~~~rl"'n-c/['-

ESB #47 (OOR C)

MBD

MASSBUS
CONNECTORS
(4)

MASSBUS
DATA
BUS PARITY
ERROR

WMCROM
PARITY
ERROR

WMC ERROR

HI ORDER 3 BITS
OF MBD LINES

TU BUS
CONNECTORS

READ
DATA PARITY
ERROR FROM
M8952

(8)

MA-7960

Figure 1-2
Figure B-10

Write Microcontroller Error Byte

Byte

DescriptiOir

Hardware register 326; ECODE counter
<15:8>

Hardware register 330; DDRjMBD A

Hardware register 331; DDRjMBD B

Hardware register 332; WMC errors (Refer to
Figure B-I0)

TM78 Front View

DRIVE
ADDRESS
SELECT
DRIVE
ADDRESS
SELECT

INTRODUCTION

APPENDICES

105

ESB #32 (CASSTA)

02
TU PORT 2
(;\ STATUS
PARITY
ERROR

CHANNELl
(TRACK 6) FATAL
CHANNEL2
(TRACK 5) FATAL
CHANNEL4
(TRACK9) FATAL

DS2:0

CHANNELO
(TRACK 7) FATAL

COLUMNS

~m.5'413'.12 ~\110

= 0-

~ ~ ~ ~
0

'" '"
<Xl

<Xl

THIS MASSBUS
PORT IS
READY

r::a:

(J(J(J(J~(J

I-

l!)

:;; :;; :;; :;; :;;

i=
a:
U ~
U
(J :;; :::l
!:!. ~ t:

ROWS

CHANNEL P

l!)

(TRACK 4) FATALEr~~

~HR~~~E~ ~ATAL1JJ/I~

ERENCED
ATTENTION
ACTIVE

CAS/MASSBUS
C BUS PARITY
ERROR

~<Xl ~ <Xl
0

l!)

ILLEGAL
MASSBUS
REGISTER

REF -

M
N

CHANNEL 3
/A::: ;:;:; ;::-;
(TRACK 3) FATAL
~"",.

l!)

CAS
CONTENTION
ERROR

C')
l!)

MA-7957

Figure B-7

CAS Port (N) Status Byte

l!)
l!)

~ ~ ~

u :;; :;; :;;

ESB #33 (CBUSST AI

g.HR~~~E8~ ~ATAL/ !l ¥ ¥ ¥ 2.
CHANNEL 5
/'/
(TRACK 1) FATAL
~

~ ~~ ~

0l0l~0')0l

~12J,1l~~

o ECC PROGRAM ROM /

V"""

\V PARITY ERROR

MASSBUS
ATTENTION

I
I

MASSBUS
TRANSFER

TU PORT 3
STATUS
PARITY
ERROR

TM78 Module Layout (Back View) Showing
Maintenance Indicators (Sheet I of 2)

MASSBUS
FAIL

MASSBUS
INITIALIZE

-5 VO LTS
OK

WMC DATA
SHIFT LEFT

MASSBUS
PORT IS
ON-LINE
MA-7958

Figure B-8
Figure 1-3

MASSBUS
DEMAND

MASS BUS C Bus Status Byte

Byte

Description

Hardware register 324; byte counter <7:0>

Hardware register 324; byte counter <15:8>

Hardware register 325; PAD counter <7:0>

Hardware register 325; PAD counter <15:8>

Hardware register 326; EeODE counter
<7:0>

104

INTRODUCTION

APPENDICES

ESB #30 (PST AT)

TU PORT 0

o
STATUS
\:V PARITY

TRANSLATOR
PROGRAM ROM
PARITY ERROR
COLUMNS

ERROR

WCSSTATUS
PARITY
ERROR

WCS
COMMAND
PARITY
ERROR

TU BUS WDS

TU BUS
WCS P

TU BUS
AMTIE P

TU BUS
TU BUS
TACHOMETER
RD P

A;-

I~.:~

TAPE UNIT
PRESENT
MA-7956

Figure B-6

TU Port Status Byte

Hardware register 50; channel P TIE bus
(Refer to Figure B-5)

Hardware register 60; TIE bus

Hardware register 104; AMTIE (TU Bus)

0..

Hardware register 241; CBUS status (Refer to
Figure B-8)

Hardware register 300; DBUS status (Refer to
Figure B-9)

Hardware register 320; WMC status

Hardware register 321; TU select 0

Hardware register 322; TU select 1

Hardware register 323; write data

,... <0

~GO ~ enGO enGO enGO enGO
lO

::;:

::;: ::;:

.. ~JI

r----.r----.

MASSBUS "B"
CONTROL BUS
WRITE PARITY ERROR

\
TU PORT 1
STATUS
PARITY
ERROR

Figure 1-3

MASSBUS "A"
CONTROL BUS
WRITE PARITY ERROR

1\
1\

-5 VOLT FAILG)
WRITE
MICROCONTROLLER
PROGRAM ROM {-;\
PARITY ERROR

g~ -%

::;: ::;: ::;:

Hardware register 114; read data
Hardware register 240; CAS status (Refer to
Figure B-7)

........ ~~

• ..= ~ ~~ ~

Hardware register 110; PORT status (Refer to
Figure B-6)

0..

-!i;

gg
o 0

~~
t-

'"t- '"t- a:. a:

a: a:

,...

en
GO
::;:

i=
i=
0.. 0..
o 0

~ i;§

ROWS
lO
lO

« «
z z

a: '"
2
::;: ~ u u

Description

5 /4 3 2
::i --'

i= ~
::J

Byte

MICROCOMPUTER
PROGRAM ROM
PARITY ERROR

TM78 Module Layout (Back View) Showing
Maintenance Indicators (Sheet 2 of 2)

.."

ciQ"
!:

.l:..

2
-I

...,

--~I~·-··~iI

c:::
-...l

I,:
lilt=;;l

~
.4:

c=::::==::Jit

rr---fo~~~"~'~~~_ I
11\'

1111

:tI

0
0

-I

5
2

:>
~

:3
g:
0;"
en

-;;:;
0
a
-<
0;"
'"I

~
2

c;l

ESB #19-27 (CHNTIE)

AMTIE

PHASE TIE
GCR=I LLEGAL 5:4

STAT=O*, POINTER MISMATCH IN GCR

PE=DEAD TRACK

STAT=l*, ANY POINTER OCCURRED

»
-c

*STATISTICS BIT
(BIT 1 IN HARDWARE
REGISTER 011-W;RPCTL)

-c

MA-7955

Figure B-5

Channel (N) Track in Error Byte

m
o

102

APPENDICES

INTRODUCTION

ESB #18 (ECCSTA)

CRC ERROR

AMTIE
OCCURRED

ECC ROM
PARITY
ERROR

POINTER
MISMATCH
CORRECTION

ACRC
ERROR

TWO TRACK
ERROR
CORRECTION
EXHAUST
FANS (2 I

UNCORRECTABLE
MA-7954

CARD
CAGE
(BEHIND PANEL)

Figure B-4

BLOWER
FAN

ECC Status Byte

Byte

Description

Hardware register 31; corrected data (CH 7:0)

Hardware register 32; ECC status (Refer to
Figure B-4)

Hardware register 40; channel 0 TIE bus
(Refer to Figure B-5)

Hardware register 41; channel 1 TIE bus
(Refer to Figure B-5)

Hardware register 42; channel 2 TIE bus
(Refer to Figure B-5)

Hardware register 43; channel 3 TIE bus
(Refer to Figure 8-5)

Hardware register 44; channel 4 TIE bus
(Refer to Figure B-5)

Hardware register 45; channel 5 TIE bus
(Refer to Figure B-5)

Hardware register 46; channel 6 TIE bus
(Refer to Figure B-5)

Hardware register 47; channel 7 TIE bus
(Refer to Figure B-5)

H7422· AB
POWER SUPPL
(MASTE R ON L Yl

HEAT
EXCHANGER

PULLEY
COVER

BLOWER
MUFFLER

Figure 1-5

•

TU78 Assemblies (Back View)

INTRODUCTION

APPENDICES
Table B-2

101

Read Microcontroller Command Codes

CMDCode

Description

00
01
02

NOP
Interblock read
Test PE ID burst
Test GCR ID burst
Test ARAID burst
Test tape mark
Test ARA burst
Normal NON-BOT read
Run RMC self-test
Test unknown ID burst
Run read channel micro's test
Diagnostic read command
Run read channel self-test
Run clear all RMC test program
Run ECC self-test program
Find gap

03
04
05

06
07
10
11

12
13
14

15
16
17

ESB #13 (RPSTA)

CORRECTED
PE
MARK 2
DATA
POSTAMBLE DETECTED
DETECTED
DATA BIT

RCP
NOT DONE

END MARK ILLEGAL 5:4
DETECTED

AMTIE

MA-7953

«'"
i~

«'"
~~

a:~
~o.

Figure B-3

I-

'"u
~

..J>

Parity Read Channel Status Byte

Wa:",

wwu

a:<no.

Byte

Description

Hardware register 25; RC PAR bits (CH P)
(Refer to Figure B-3)

Hardware register 26; postamble detected (CH
7:0)

Hardware register 27: data (CH 7:0)

Hardware register 30; CRC

100

APPENDICES

Table B-1

INTRODUCTION

Read Microcontroller Status Codes (Cont)

Status

Meaning

236

Read path fault 2; 7 or more
M8950 BOARDS found illegal 5 to
4 translations.

":::>

Unexpected IBG in data;
probably creased tape (7 or
more AMTIES active)

241

261

Postamble long

262

Postamble short

I0.....

0 0

377

ESB #7 (RCMLP)
07

-c
co
52

RM:C CMD:7:0

0
0

9~D
~ ~
e
a.

.!!1

;;:

RUN CONTINUOUS
(CODES 01-06)

:::>

THIS BYTE CONTAINS THE LAST
COMMAND SENT TO THE M8953
READ MICROCONTROLLER.

.S:
c:
MA-7952

!D
0

Figure B-2

Read Microcontroller Command Byte

O~D
.....

<:(

Description

Hardware register 23; mark 2 (CH 7:0)

E
0

....

0
~
~

Hardware register 24; end mark (CH 7:0)

t::
C':!

1.::

-l

Byte

::J
I-

I-

co(/)

r--

~<:(co~~

a.6"':'NM

r-;-

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01)

fi:

APPENDICES

INTRODUCTION
Table B-1

Read Microcontroller Status Codes

Table 1-1

TV7S Controls

Control

Function

Status

Port
Select
Switch

It selects the MASSBVS I/O port(s)
allowed to send commands to this
tape transport.

Status resulting from ECC self-test command
101

102
Switch
Position

Transport connected to
MASSBUS port A

104

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)

Read path passed self-test
Read path failed self-test

Status resulting from an M8950 self-test command

106

ECC sequencer passed self-test
ECC sequencer failed self-test

Status resulting from an M8953 self-test

Transport connected to
MASSBUS port B
2

Meaning

Function

103

Read channel tests all passed

Status resulting from a clear all test command for velocity testing of drive by microcode

1
201

First tach pulse
Last tach pulse (eleventh) (ten
spaces)

Status resulting from a sample density command
LOAD/
REW

It starts one of three sequences

210
1. With no tape in path, it initiates a
load sequence.

2. With tape in path but not tensioned,
it starts a midreelload sequence.
In a midreelload sequence the
tape loads and runs in reverse
direction to BOT.

211

212

NOT CAPABLE found
GCR ID found
PE ID found

Status resulting from a write test of IBG, PE ID, GCR ID,
ARA ID, or ARA burst

220

Bad status (write test)

Status resulting from a tape mark test command
3. With tape in path and tensioned, and
the transport off-line, the tape
rewinds to BOT. If the tape is at
BOT or if the transport is on-line,
no action occurs.
ON LINE
UNLOAD

RESET

It switches the transport off-line or
on-line.
If the TU78 is off-line, it causes the
tape to rewind and unload. If the tape
is at BOT, it unloads. If the TU78 is
on-line, button has no effect.

Terminates all functions and clears a
load fault.

222

Good tape mark found on tape
status

Status resulting from a NON BOT command (read or write
FWD or REV, GCR or PE)
230

ARA ID found (not record or TM)

231

Tape mark found

234

Preamble end not found

235

Read path fault 1, too many
M8950s have been fataled to
continue record processing

INTRODUCTION

Table 1-2 TV7S Indicators

APPENDIX B
EXTENDED SENSE BYTES

Indicator

Meaning

Power

DC and secondary ac power are present.

BOT

Tape is at BOT.

On Line

Command code being executed on last error

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

Interrupt code from last error

1. ON LINE button is pressed.

Failure code last error

2. External rewind unload command
is received.

Hardware register 0; read path write fail bits

3. Vacuum column interlock is broken.

Hardware register 1; read path diagnostic bits

4. AC power is lost.

Hardware register 2; read path status (Refer to
Figure B-1)

5. RESET button is pressed.

Hardware register 3; read path command loop
(Refer to Figure B-2)

Hardware register 20; AMTIES (CH 7:0)

Hardware register 21; RC DONE (CH 7:0)

Hardware register 22; illegal 5-4 (CH 7:0)

Byte

Description

6. Front door opens.
File
Protect

Tape reel without a write enable ring has
been loaded on 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.
2. Load sequence has failed to load tape
from a 216 mm or 178 mm (8.5 in or
7 in) reels.

ESB#6 (RSTAT)

READ PATH MICROCONTROLLER
STATUS CODES ARE RETURNED IN
THIS BYTE. TABLE B-1 IDENTIFIES
EACH CODE AND IT'S MEANING.

1600

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

6250

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

MA·7951

Figure B-1

Read Path Status Byte

1.6 MAINTENANCE CONTROLS AND
INDICATORS
Maintenance controls and indicators may be found on
the TM78 logic gate (front and back), the TM78 power
supply (H7422), the TU78 logic cage, and the front of
the TU78 base assembly.

INTRODUCTION

APPENDICES

1.6.1 TM78 Controls and Indicators
Figure 1-2 shows the front of the TM78 logic gate and
details the maintenance controls. The maintenance panel
is described in Chapter 2. To the right of the maintenance panel is a DIP switch matrix. The DIP switches
select the MASSBUS drive address for both ports and
sets either or both ports on or off-line. A dual port TM78
is considered off-line for maintenance purposes only
when both ports are placed off-line.
Figure 1-3 shows the back of the logic gate and details
some of the maintenance indicators that may be used for
troubleshooting. Table 2-3 lists the indicators and describes their functions.
Figure 1-8 shows the front of the H7422 power supply
and details the maintenance indicators and adjustments.
1.6.2 TV78 Controls and Indicators
Figure 1-9 shows a detail of the base assembly and
points out the door safety interlock switch. This switch
must be defeated to perform certain maintenance adjustments. To defeat the switch pull its actuator arm down
and out with a spring hook.
The rest of the TU78 maintenance controls and indicators are on PCBAs in the card cage assembly (Figure
1-6). Table 1-3 lists the TU78 maintenance controls and
Table 2-3 lists the indicators.

1.7 TooIS
In addition to the standard DIGITAL tool kit, the following tools are needed to service the TM78/TU78.

DEC
Part
Description

Number

Included
in
Spares
Kit

Dual trace
oscilloscope with
two XlO/Xl probes

Digital voltmeter

Two multilayer
dual-height module
extenders

W900

Reel motor
centering tool

29-23206

Yes

....

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lllJ !

, ....

"" .... , ' , .

INVERT MASSB us
DATA PARITY

I I

-I

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MASSBUS
DRIVE
SELECT
(READ ONLY)

INVERT MASSB US
CONTROL PAR TY
INVERT MAP P \ R I T Y -

"tJ

m
Z
o
(")

MASSBUS REGISTER SELECT
(READ ONLY)

BLOCK SENDIN G

CJ)

COMMAND TO iBI
SIMULATE SCL <

SELECTED MDIB (READ ONLY)

SIMULATE EB

(VALID DURING MAINTENANCI
MODE ONLY)

SIMULATE OC
SIMULATE AT N
MDI B SELECT
MASSBUS FAI

(READ ONLY)

MASSBUS RUN (READ ONLY)
NOTE: BITS 21 AND 22 ARE READIWRITE
FOR DIAGNOSTIC TEST PURPOSES

MASSBUSWCL K (READ ONLY)
MASSBUS EXC (READ ONLY)

ONLY

MASSBUS CTO D (READ ONLY)

Figure A-IS

Diagnostic Register

--,....---------

r- - -

/
/

ACON

AC
~

AC OFF

ON,,@)

+5V _

_ +5V®:

ADJ.
I

I
I

REGULATOR 2
H7441

1
I
I

REGULATOR4
H7441

L _ ___________1 _ _ _ _ _ _ _ _ _ _ _
I
I
.
I
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I

-5V
ADJ.

1@2+15V_U--15V@31
I
ON
ON

Z
--I

REGULATOR 1
H7490

REGULATOR 3
H7476

:xl

1
MA-7512A

o
c

Figure 1-8

H7422 Power Supply Showing Maintenance
Indicators and Controls

....w

APPENDICES

INTRODUCTION

DOOR
INTERLOCK

0
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p
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~

.
~

i" ~
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a

. 11

....

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ex:
Figure 1-9

~
~

Door Safety Interlock Switch

....

""0
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Description

DEC
Part
Number

Included
in
Spares
Kit

M
N

a
a

...
N

Reel flange
locating bar

29-23207

PCBA extender

29-23218

Yes

Lower restraint
tube fitting

29-23228

Yes

Differential
pressure gauge
(0-40 inch H 2O)

29-11650

Yes

Differential
pressure gauge
(0-5 PSI)

29-11636

Yes

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N

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INTRODUCTION

APPENDICES

DEC
Part
Number

Included
in
Spares
Kit

Portable accessory
package for gauges
(2 needed)

29-11647

Yes

Tachometer (decimal
readout)

29-11635

Yes

Tape crimper

47-00038

Yes

r--

Xcelite handle

29-10562

Yes

7 inch extension

29-11625

Yes

5/32 inch X 4 inch
Ballpoint hex driver

29-11630

Yes

Master skew tape
(1200 ft)

29-19224

Magna-See tape
developer

29-16871

50X microscope with
graticule

29-20273

Heat sink compound

90-08268

Yes

Inspection mirror
(dental type)

29-19663

Cleaning kit

TUCOI

(comes
with
TU78)

Standard output
tape

29-11691

Description

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INTRODUCTION

APPENDICES

Table 1-3 TV7S Maintenance Controls

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INTRODUCTION

APPENDICES

DEC
Part
Number

M8953
M8955
M8956
M8957
M8958
M8959
0
0

....

;::!

)

M8960
54-14174
H7476
H7490
H7441
54-14192

Description

Read path microcontroller
module
TU port module
MASSBUS data interface module
Common address space module
Write translator module
Write micro/byte assembly
module
Microcomputer module
Maintenance keypad/display
Power supply regulator ± 15.0 V
Power supply regulator -5.0 V
Power supply regulator + 5.0 V
AC/DC low board

1.8.2 TU78 Spares Kit (A2-W0341-10)
The following lists the contents of the TU78 Spares
Kit.

DEC
Part
Number

29-23766
29-23770
29-23769
29-23763
29-23762
29-23764
29-23765
29-23231
29-23218
29-23996
29-23989
29-23991
29-23220
- 29-23259
70-17382-15
29-10562
29-11625
29-11630
29-11001
29-11635

Description

GCR/PE preamp 1 PCBA
Interconnect Fl PCBA
MIAPCBA
WRITE PCBA
READPCBA
Control M2 PCBA
Capstan/regulator PCBA
Reel servo PCBA
Extender PCBA
Compressor belt, 50/60 Hz
Blower belt, 50 Hz, Lo
Altitude
Blower belt, 60 Hz, Lo
Altitude
Muffler
Air filter
15 ft TU bus cable
Handle
7 inch extension
5/32 inch ball-end allen driver
Phillips screwdriver blade
Tachometer

INTRODUCTION

DEC
Part
Number

Description

29-11636
29-11650
29-11647
29-23206
29-23207
29-23228

Gauge, 0-5 PSI
Gauge, 0-40 inch H 20
Accessory kit for gauges (2)
Centering tool
Locating bar
Tube fitting

APPENDICES

I'l

"
0>

0
0

:;;

1.9 RECOMMENDED SPARES LEVELS (RSL)
In addition to the spares kit contents, the following
parts are recommended to repair 98 percent of all possible failures.

M
0

1.9.1 Additional TM78 RSL Parts
The following are additional RSL parts for the TM78.

«
I«
0
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a:
w
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II)

DEC
Part
Number

Description

BC06S-25
12-10930-01
12-11079-00
12-11164-04
70-17381-OD
70-17400-00

25 ft MASSBUS cable
230 Vac fan
Pushbutton switch
DIP switch
Flat cable
Backplane

1.9.2 Additional TV78 RSL Parts
The following are additional RSL parts for the TU78.

0
-l
0

«
0
-l

I-

~
~

CI)

(;
w

DEC
Part
Number

Description

12-17916-02
29-16280-00
29-23216-00
29-23217-00
29-23236-00

Fan, tube axial 230 V
Switch, MICRO
Sense assy, reel
Sense assy, pack
Motor assy, reel

29-23238-00
29-23239-00
29-23242-00
29-23243-00
29-23246-00

Switch, pressure
Switch, pressure
EaT IBOT assy
TIP assy
Transducer assy, vacuum

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a:
w
1->:::IIa.-a:
:2: a: 0
O«a:
Ua.a:
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a:0
Ua:
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...

-l
0
a:
w
1->-1ZI-O-a:
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LL:

APPENDICES

Table A-2

INTRODUCTION

Nondata Transfer Function Codes (Cont)

Function
Code
(Go Bit
Included)

Name

Description

ERG GCR§

Erases three inches
of tape, sets GCR

Close File PE §

Writes two tape
marks, spaces
reverse one, sets PE

Close File GCR §

Writes two tape
marks, spaces
reverse one, sets
GCR

SPACELEOT

Spaces forward until
two tape marks,
spaces reverse one

SPACE FWD
FILE/LEOT"

Spaces forward to
tape mark, stops if
two successive tape
marks (logical end
of tape)

*Sometimes interrupts when rewind starts; always interrupts after tape motion has stopped.
tSense registers are valid as long as the ATIN bit is set.
*Erases at least 3.05 m (10 ft) beyond the EaT marker.

§ Recording format is ignored except when tape is at load point
(BOT). It is specified by bit 1.

/I Do not use after any reverse operation; the TM78 may skip

DEC
Part
Number

Description

29-23247-00
29-23248-00
29-23249-00
29-23250-00
29-23251-00

Circuit breaker
Valve assy, vacuum
Valve assy, pressure
Bearing, air
Bearing, air

29-23252-00
29-23257-00
29-23280-00
29-23287-00
29-23297-00

Bearing, air
Compressor
Motor, gear drv
Motor, ac
Switch, backwrap defeat

29-23298-00

29-23308-00
29-23321-0P
29-23322-00

Blower assy (Below SN
SP002386)
Blower assy (SN SP002386
and above)
Relay reed SS 12 Vdc
Cable, flat ribbon (AMTIE)
Thread block 2

29-23323-00
29-23324-00
29-23325-00
29-23326-00
29-23475-00

Thread block 4
Thread block assy
Thread block assy
Thread block assy
Hub reel

29-23767-00
29-23768-00
29-23771-00
10-11643-00
12-14405-00

Head, R/W
Motor assy, capstan
Controls assy
18,000 MFD 25V + 75-10%
Door, tape transport,
front

29-23208-00
29-23209-00
29-23211-00
29-23215-00
29-23219-00

Hub, machined
Flange, front
Interconnect D 1
Door assy, buffer box
Spring, compression

29-23222-00
29-23223-00
29-23241-00
29-23255-00
29-23256-00

Spring, bellville
Washer
Cleaner, tape
Guide plate .oR"
Guide plate "C"

29-24013

over an LEOT located where direction was reversed.

INTRODUCTION

DEC
Part
Number

Description

29-23258-00
29-23279-00
29-23283-00
29-23284-00
29-23285-00

Transformer
Filter, RFI
Guide, Air
Hub, motor 50 Hz
Hub, motor 60 Hz

29-23286-00
29-23288-00
29-23309-00
29-23310-00
29-23311-00

Catch, spring
Receptacle, fastener
47000 MFD 15 W VDC+ 75%-10%
61000 MFD 50 W
VDC+ 100%-10%
RECT, BRDG 25 A 100 PN

29-23312-00
29-23320-00
29-23361-00
29-23655-00
70-17143-00

RECT, BRDG 10 A 100 A
33020 W 10% WW
Cap plug
Kit, vac hose/tubing
Fan assembly TU78

90-07221-00
90-08835-00
90-08838-00
29-11691-00
29-16871-00

Fuse, reg blow, 5 A, 250 V
Fuse, reg blow, 20 A, 32 V
Fuse, reg blow, 10 A, 32 V
Tape MSTR OTPT 1200Xl/2
Magnasee

29-19224-00
29-20273-00
47-00038
90-08268

Tape, master skew 1200
Microscope 50 X
Tape crimper
Thermal compound

APPENDICES

Table A-2

Nondata Transfer Function Codes

Function
Code
(Go Bit
Included)

Name

Description

NOOP

Generates a unique
NO OP interrupt code

Unload

Unloads tape and
interrupts
immediately

Rewind*

Rewinds tape and
interrupts when done

Senset

Puts status
information into CAS

Data Security
Erase:\:

Erases remainder of
tape and rewinds

WTMPE §

Writes phase-encoded
tape mark

WTMGCR§

Writes GCR tape mark

SPFWDREC

Spaces forward
record, stops if
tape mark

SPREVREC

Spaces reverse
record, stops if
tape mark or BOT

SPFWD FILE

Spaces forward file
(to tape mark)

SPREV FILE

Spaces reverse file
(to tape mark)

SP FWD EITHER

Spaces forward
either record or
file

SP REV EITHER

Spaces reverse
either record or
file

ERG PE §

Erases three inches
of tape, sets PE

APPENDICES

INTRODUCTION

1.10 RELATED DOCUMENTS
The following list describes documents related to the
TU78 subsystem.

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z
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EK-OTM78-UG

Descri ption,
programming,
and
installation
information of
the TM78

TM78
Magnetic
Tape
Formatter
Technical
Manual

EK-OTM78-TM

Theory of
operation,
programming
information,
install ation,
and maintenance
of the TM78
Formatter and
H7422 Power
Supply

TU78
Magnetic
Tape
Transport
User's
Guide

EK-OTU78-UG

Description,
installation
instructions,
and operating
procedures for
the TU78.

TU78
Magnetic
Tape
Transport
Technical
Manual;
Volume 1

EK-ITU78-TM

Schematics and
logic prints
of TU78

TU78
Magnetic
Tape
Transport
Technical
Manual;
Volume 2

EK-2TU78-TM

Description,
ins talla tion,
operation,
theory, and
maintenance
of TU78

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Contents

TM78
Magnetic
Tape
Formatter
User's
Guide

Document
Number

(;

cry

Title

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INTRODUCTION

Title
TU78
Magnetic
Tape
Transport
IPB

Document
Number
EK-TU78-IP

APPENDICES

Contents
Exploded views
and parts lists
of TU78 and TM78

0
0

874 Power
Controller
IPB

EK-00874-IP

RH20
MASSBUS
Controller
Unit
Description

EK-RH20-UD

Exploded views
and parts lists
of 874

a:g~

0
N

Description of
RH20 MASSBUS
controller

M
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a
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t.n
0

RH780
MASSBUS
Adapter
Technical
Description

EK-RH780-TD

Programming and
theory of RH780
MASSBUS adapter

r--

Field
MPOI061
Maintenance
Print Set

Engineering
drawings for
TU78 mechanics
and cabinet,
engineering
dra wings and
parts lists for
TM78 mechanics
and logic,
TM78 power
supply chassis,
+5 volt
regulator,
± 15 volt
regulator, and
-5 volt
regulator

(j)

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1.i:

INTRODUCTION

APPEND ICES

1.11 SYSTEM DIAGNOSTICS
The following are system diagnostics for both the
TU78 and TM78.
Diagnostic Name
Title
0
0

C"J

w
0

L!)

(/)

!z
~

a:
:c

«'=~

f-a:«W
«::>a: U
O~W~
(/)
Z W
wO
f-O
O(/)
Z:2

W~~:;(

....J

0
W_W

fa..
ll.

ll.C: W
::>:s:t;
f- -a:ll.
a.. OW

r-0

CXl

(/)

fW
f0

:s:
W
a:

(/)

'=
Z
::>
W
a..
«
f-

:::

ZW
_a..
Z«
Zfto

W
W 0

o 0

o :2
:2 a:
OW U
Zo..O

o- ~II 0II

::>Z
f-:s:
W
a:

W
Z
::::i

::>
f-

a..

ZfW

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(/)

W
a:

«:c
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f-

a..

....J
Z

>(/)

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::>
f«
f(/)

(/)

W::>
....JtO
to(/)
«(/)
....J«
:;(:2

a:(/)a::2
«(/)0
:C«o..
(/):2

'"0

fZ
::>W

f-~

::>0
f-«
W
a:

a:
a..

DECSYSTEM-20

VAX

Control
Logic Test

DFTUI

EVMAE

Data
Reliability

DFTUJ

EVMAA

APPENDICES

TROUBLESHOOTING

2.1 INTRODUCTION
This chapter gives a short description of the tools
available for troubleshooting a failure in the subsystem.
They include troubleshooting flows, on-line and in-line
diagnostic programs, error log summaries, status indicators, and a maintenance panel for exercising the formatter/transport off-line.
2.2 ON-LINE DIAGNOSTICS
Table 2-1 lists and describes the on-line (system level)
diagnostics available for each hardware family.
2.3 IN-LINE DIAGNOSTICS
A total of 37 in-line microdiagnostics run continuously
when the subsystem is idle. If a microdiagnostic fails to
operate correctly, the TM78 raises an attention interrupt
to the host CPU(s). Each microdiagnostic may be called
up individually for scope loops or repair verification.
This is done through the TM78 maintenance panel.
Table 2-2 lists each microdiagnostic and its test number.
2.4 ERROR LOGS
All DEC operating systems, under which the TU78
runs, support an error logging scheme. At a minimum,
all MASS BUS registers are read and stored away each
time a hard or uncorrectable error occurs. MASSBUS
registers are listed in Appendix A. As an error log option,
the extended sense summary may also be read and stored
away. The extended sense summary is a 60-byte field of
internal TM78 and TU78 registers. Extended sense tables for each of four possible TU78s are updated after
each error. The extended sense bytes are listed in Appendix B.
2.5 STATUS INDICATORS FOR
TROUBLESHOOTING
In addition to the TM78 maintenance panel, a total of
29 LED indicators are available for troubleshooting.
Table 2-3 lists each indicator, its function, and location.

APPENDICES

TROUBLESHOOTING
Table 2-1

TM78/TU78 Diagnostics

DECSYSTEM-20

VAX

Description

EVMAE

The Control Logic Test
tests MASSBUS controller
and TM78 formatter logic.
It also tests subsystem basic
command functions while
checking for proper tape
motion timing. The test must
be run from each CPU
separately, through both
MASSBUS ports (if dual port
option is present). The test
provides error information
to the user via console or
lineprinter.

EVMAA

The Data Reliability Test
tests TM78 circuitry by
writing and reading predetermined data patterns and
recording modes. The test
provides error information to
the user via console or
lineprinter. The test may be
run in dual port mode (from
dual CPUs) driving two or
more transports.

Control Logic Test
DFTUI
o
o

a:
0

«
o

2
u
N

("')

::J

L!)

o
U
o
a:
o

Data Reliability

u
w
a:

DFTUJ

o
o"

co
o
f-

o
M

u
(J)

::J

:::.::
(J)

a:
w

(!l

w
a:

...J

I-

LL.

!z ;!
o

« ~
I-

a:
w

(J)

2.6 ERROR CODES
The TM78 sends an interrupt code and a failure code
to the host CPU at the completion of any command.
These same codes are put into the maintenance display
at the completion of a command issued through the
maintenance keypad. Table 2-4 lists each interrupt code
in numerical order followed by each failure code that
could occur within that interrupt code.
Note that certain interrupt codes imply that the command completed without error or a nondata record was
found (codes 01-06). Others indicate that the transport
was not in the correct state to operate on the command,
or that another command is necessary (codes 07-27).
Still others indicate a possible hardware or software failure (codes 30-32). Interrupt code 77 is a unique code in
that it applies only to keypad commands.

Table 2-2
Test
Number
0
1
2
3
4
5
6
7
10
11
12
13
i4
15
16
17
20
21
22
23
24
25
26
27
30
31
32
33
34
35
36
37
40
41
42
43
44

APPENDICES

TROUBLESHOOTING
In-Line Self-Test Microdiagnostics

Description
Write microcontroller self-test (M8959)
Translator ROM parity test (M8958)
Read path microcontroller self-test (M8953)
Read channel 0 (slot AB12) self-test
Read channell (slot AB13) self-test
Read channel 2 (slot AB 14) self-test
Read channel 3 (slot AB 15) self-test
Read channel 4 (slot AB16) self-test
Read channel 5 (slot CD13) self-test
Read channel 6 (slot CD14) self-test
Read channel 7 (slot CD 15) self-test
Read channel P (slot CD16) self-test
Read path error corection self-test (M895 1)
Microcomputer RAM memory self-test (Loc
40000-40777)
Microcomputer RAM memory self-test (Loc
41000-41777)
Microcomputer RAM memory self-test (Loc
42000-42777)
Microcomputer RAM memory self-test (Loc
43000-43777)
Microcomputer RAM memory self-test (Loc
44000-44777)
Microcomputer RAM memory self-test (Loc
45000-45777)
Microcomputer RAM memory self-test (Loc
46000-46777)
Microcomputer RAM memory self-test (Loc
47000-47777)
Loop write-to-read at TV port 0 in GCR
Loop write-to-read at TV port 0 in PE
Loop write-to-read at TV port 1 in GCR
Loop write-to-read at TV port 1 in PE
Loop write-to-read at TV port 2 in GCR
Loop write-to-read at TV port 2 in PE
Loop write-to-read at TV port 3 in GCR
Loop write-to-read at TV port 3 in PE
Loop write-to-read at MIA 0 in GCR
Loop write-to-read at MIA 0 in PE
Loop write-to-read at MIA 1 in GCR
Loop write-to-read at MIA 1 in PE
Loop write-to-read at MIA 2 in GCR
Loop write-to-read at MIA 2 in PE
Loop write-to-read at MIA 3 in GCR
Loop write-to-read at MIA 3 in PE

0
0

0
N

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I-

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ex:

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N
www
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ti:

TROUBLESHOOTING

APPENDICES

Table A-I

Data Transfer Function Codes

Table 2-3 Troubleshooting Indicator Functions
Indicator
Number
on Figure

Function
Code
(Go Bit
Included)

Name

Description

WRTCKFWD

Write Check Forward - Tape
subsystem reads one record in
a forward direction. Data is
checked in RH controller.

WRTCKREV

Write Check Reverse - Tape
subsystem reads one record in
a reverse direction. Data is
checked in RH controller.

WRITE PE*

Write phase-encoded records

WRITE GCR*

Write group-coded records

READ FWD

Read records forward

EXSNS

Read extended sense error log

READ REV

Read records reverse

*The recording density format is ignored unless the tape is positioned at load point. At load point, the write command specifies the recording format of the entire tape.

Function

Possible
Failing
FRU

1-3

A channel has failed.
These nine indicators
reflect the quality
of the data stream
for each channel or
track. They indicate
loss of SYNC or track
dropout. Nonlatched

transport
• TV78
• TV Bus cable (n)B
• M8950

1-3

A parity error has
occurred in the ECC
microcontroller.
Latched

• M8951

1-3

There has been a TV
bus status parity
error. Wrong Parity
was received at the
TV port on the WCS
lines. Latched

• TV bus cable (n)A
• TV78 MIA
• M8955

1-3

-5 V for the
MASSBVS
transceivers is out
of specification.
Nonlatched

• H7490
• H7422
• TM78 backplane

1-3

Wrong parity was
received at the
MASSBVS port on a
control bus command
write. Latched

• MASSBVS cable
• RHXX controller
• M8957

1-3

A parity error has
occurred in the
translator microcontroller. Latched

• M8958

1-3

A parity error has
occurred in the write
microcontroller.
Latched

• M8959

*The normal state of the indicator is off.

TROUBLESHOOTING

APPENDICES

Table 2-3 Troubleshooting Indicator Functions (Cont)
Indicator
Number
on Figure
1-3

1-8

Function

Possible
Failing
FRU

A parity error has
occurred in the
microcomputer
program ROM.
Latched

• M8960

+ 5 V regulator 2 is

H7441
• Any
module in

ok (supplies TM78
read path).

0
0

lOt + 5 V regulatOi 4 is
ok (supplies TM78
write path.
MASSBUS ports TU
ports and microcomputer.

•

slots 10<16

C")

• H7441
• Any module in

1-8
1-8
1-8

1-6

llt - 5 V regulator I
is ok.

12t + 15 V regulator 3
is ok.
13t - 15 V regulator 3
is ok.
14t Power is being
applied to the H7422
power supply.

~I-;:;:
::::>ai«

~
LL.
I-

slots 1<9

LL.o~

O:(!)m

wo «

~zl-

z«o
«wI0:,....0:
l-(5w
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Iw
«
~
0

1.0

to
0

1-8

0
(!)

•
•
•

H7490
M8956 (slot I
or 3)
M8957 (slot 2
or 4)

co
0

• H7476

•
• H7476
• AnyM8950
•
•

breaker tripped
H7422 power cord
H7422 supply

15t A command or
command address on
the WCS lines was
received at the MIA
with wrong parity.

• TU bus cable (n)A
M8955
• TU78
MIA
•

16t MIA PCBA maintenance switch S4 is in
MANUAL position.

•

a:
W

«
>
0

CI)

::>
l«
ICI)

w
..J
m

«
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<i:
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w
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0:
0

~
·So
~

"
rIl

::I

U5
"0

"2
e::0

;:!

«
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I-

*The normal state of the indicator is off.
tThe normal state of the indicator is on.

(!)

Flip switch to
AUTO

....

Any M8950

• H7422 circuit

....~

::I

01)

APPENDICES

TROUBLESHOOTING

Table 2-4 Interrupt Code to Failure Code
Int
Code Name
01

wi
. ~ ~ ~ ~ ~
0
to

- - - --

~ ~

za: '"

~ ~

8~ ~~ I~~

r-r-

b ~ ~ 0
g

g:.

~§

~<n ::;
~
0

-~ 0

a: I:J
'"
-' ::;
a:

-::
W

~~
a:_

~~~

~Io _

Extended sense data
updated and contains
something of interest

TAPEMARK*

Always zero

BOT*

01 -

Command was issued with
tape at BOT

02 -

Saw BOT indicator after
tape motion started

-;;:-

03 -

ARA ID detected

00 -

Extended sense data not
updated

01 -

Extended sense data
updated and contains
something of interest

b z zz
<n a:
8~

b-~

~~ _ 0~

F-i

S
r--

~
I-

~ ~

'a:z"

:I:

I~! ~I ~ ~

>a:
Wo-

188 8 g r-

8i§l~i~ ~!~
0::

r-==-

'"'

"0
"0

-<
0
00

t-~~

I ~

-2-

~J~l~~~
~

EOT*

0-'

z c

01-1 N

;::

o~ - e - 0 0
'" ~
t5 ~

~ [I

I-

~~ ~

o
o o8
0

;;

r-..
'"

01 -

6z §z §z ~z ,~

o!i:i ~~
a:

~ ~

Extended sense data not
updated

~ ~ ~ ~I~ ~

f--f-- N

~Ii'i

I-

;j'

d~!~

r- o a:

;; 0

~-0

::.l

~ ~ ~ rr ~ ~
~
~ bt~ 5 b
~~
Z!Z z!z
a: :;;(
~ ~

00 -

~ ~ w0 -w1 Nw Mw
"'" Ci ~ 8 o Cl c Cl

-= -i-~

00
<n

§ §r-

...........

8~8

'c"

.-.-

DONE*

Failure Code

f"-

LOG ICAL EOTt

Always zero

~
"0

NO oPt

Always zero

t::
ell
0
N

REWINDINGt

Always zero

FPT*

Always zero

NOTREADY*

01 -

TU is on-line but not
ready (Possible when TU
is manually rewound or
loading)

02 -

Fatal error has occurred
and this command cannot
be performed until error
status has been presented
and a TM CLEAR received

0
.... N
"0'" 10
........
.- - .- ........ ;:: ~ N
C")

((I

In ~ ~ n • ~ ~ ~ ~ ~
!"

- 1-

.(
~

::s
'"'

*The interrupt code is used for nondata transfer or data
transfer.
tThe interrupt code is used for nondata transfer only.

TROUBLESHOOTING

Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
03 -

Access to TV is allowed
but TV is either
rewinding or doing a DSE
from another MASSBVS or
keypad command

NOT AVAIL *

Always zero

OFF LINE*

Always zero

NOT
EXECUTABLE*

Always zero

NOT CAPABLE*

01 -

No record found within 25
ft (7.6 m) of tape

02 -

ID burst neither PE or
GCR

03 -

ARA ID not found

04-

No GAP found after ID
burst (PE) or ARA ID
burst (GCR)

ON LINE:!:

Always zero

LONG REC§

00-

Extended sense data not
updated

01-

Extended sense data
updated and contains
something of interest

00-

Extended sense data not
updated

01-

Extended sense data
updated and contains
something of interest

01-

CRC error, ACRC error,
pointer mismatch,
uncorrectable or
two-track error set in
ECCST A register (This
code generated by write
GCR operations)

SHORT REC§

RETRY §

APPENDIX A
SUBSYSTEM MASSBUS
REGISTERS

CHECKS AND ADJUSTMENTS

Table 3-3

Vacuum and Pressure Valve Components

Reference

Description

A
B
C
D
E
F
G
H
I
J
K
L
M
N

System vacuum test point
Reel motor connections
Butterfly valve adjustment screw
Takeup reel vacuum adjustment screw
Vacuum present switch
Takeup reel vacuum port
Tape on reel switch
Vacuum input (to pneumatic assembly)
Butterfly valve lock nut
Air bearing pressure adjustment screw
Pressure input (to pneumatic assembly)
Thread block pressure adjustment screw
Thread block pressure port
Air bearing pressure port

TROUBLESHOOTING
Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
02-

CRC error, ACRC error or
uncorrectable set in
ECCSTA register (This
code generated by read
GCR operations)

03 -

Uncorrectable error set
in ECCST A register (This
code generated by read PE
operations)

04-

AMTIE, pointer mismatch,
uncorrectable, two-track
error or single-track
error set in ECCSTA
register (This code
generated by write PE
operations)

05 -

At least one bit set in
ECCST A register

06-

At least one write fail
bit set in RPFAIL and
RPA TH registers (This
code generated by write
PE operations)

07 -

More than one write fail
bit set in RPF AIL and
RP ATH registers (This
code generated by write
CR operations)

10-

RSTA T contains bad code

11-

GCR characters from WMC
and RMC do not match
(This code generated by
write PE operations)

*The interrupt code is used for nondata transfer or data
transfer.
tThe interrupt code is used for nondata transfer only.
:j:The interrupt code is used for TM78 initiated.
§The interrupt code is used for data transfer.

TROUBLESHOOTING

Table 2-4

CHECKS AND ADJUSTMENTS

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
12 -

MASSBUS data bus parity
error (write)

13 -

Record length incorrect
during retry opposite
attempt; invalid data has
been transferred

READOPP§

UNREADABLE § Same as Int Code 22

ERROR§

Same as Int Code 22

...J

;;:
I-

w
0

Same as Int Code 22

...J

<t:

EOTERROR§

Same as Int Code 22

:::>

BADTAPE*

Same as Int Code 22

(f)
(f)

a:
0...

TM FAULT A*

01-

Illegal command code

02-

Data transfer command
issued while nondata
transfer command in
progress on same tape
unit

e='
'"'"
~

~
...J

;;:
03 -

04-

05 -

WMC error; check
ECODE register for
reason - may be Illegal
Format or Skip Count
codes
RUN not received from
MASSBUS controller
Command read from
RMC register RCMLP
did match command
loaded into RCMD
register

06-

ECC ROM parity error
(M8951)

07 -

XMC ROM parity error
(M8958)

I-

>
...J
<t:

:2
:::>
:::>

"0
C
ell
~

E
='
='

(.)

ell

<t:

"<t

e='

CHECKS AND ADJUSTMENTS

TROUBLESHOOTING

Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

!Ifl[
Rl

10-

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Verify
ID Burst command
loaded during write
of BOT area)

11 -

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Verify
ARA Burst command
loaded during write
of BOT area)

12-

Command read from
RMC register RCMDP
did not match command
loaded into RCMD
register (this code
generated when Verify
ARA ID command
loaded during write
of BOT area)

13 -

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Verify
Gap command loaded
during write BOT area)

SUPPLY POSITION ADJUST
SUPPLY GAIN
TAKE-UP POST ION ADJUST
TAKE-UP GAIN
PACK SENSE (LOW TAPE) ADJUST

EOT/BOT ADJUST

000 TP~D~~~H
• • • •

Failure Code

\01

0
1

TPl TP2 TP3 TP7~
W1

~101
1

lot
lot

"="
W3

)21
REMOVE PIN 1 BEFORE
INSTALLATION

Figure 3-3

Interconnect F1 PCBA
b. Current Model

*The interrupt code is used for nondata transfer or data
transfer.
tThe interrupt code is used for nondata transfer only.
tThe interrupt code is used for TM78 initiated.
§ The interrupt code is used for data transfer.

TROUBLESHOOTING

Table 2-4

CHECKS AND ADJUSTMENTS

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
14-

15 -

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Read
ID Burst command
loaded during read
of BOT area)
Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Verify
ARA ID command
loaded during read
of BOT area)

r - - - - R I SUPPLY POSITION ADJUST

~
r

TP7

•

TAKE-UPPQSITION ADJUST

RI7 PACK SENSE (lOW TAPE) ADJUST

R22 EOT/BOT ADJUST

UUUT~4 T:slU1:6 ,101--,-"-------"--',1,0 ,
I,

JoI

0-=-<>

1>-=-0

16-

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Verify
Gap command loaded
during read of BOT
area)

17 -

Command read from
RMC register RCMLP
did not match command
loaded into RCMD
register (this code
generated when Find
Gap command loaded
during Erase Gap
routine)

20-

WMC LEFT failed to
set in Extended Sense
routine

21 -

PE WRITE PE set in
INTST A register
(M8958)

R31
SUPf>LYGAIN
RJO
TAKE UP GAIN

Figure 3-3

Interconnect Fl PCBA
a. Early Model

J21

REMOVE PIN I BEFORE
INSTALLATiON

CHECKS AND ADJUSTMENTS

TROUBLESHOOTING
Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

n f'''

~R13}TRACK5
PREAMPLIFIER

Failure Code
22-

XMC DONE did not set
(M8958, M8959)

23-

WMC ROM PEor
RD PE set in
WMCERR register
(M8959, M8952,
M8951)

01-

TV status parity error
(MIA)

02-

TV command parity
error (M8955)

03-

Rewinding tape went
off-line

04-

Tape went not ready
during DSE

05-

TV CMD status
changed during DSE

06-

TV velocity never came
up to speed

07-

TV velocity changed
after up to speed and
writing started

10-

TV CMD did not load
correctly to start tape
motion in selected
function routine

J902TO
READ PCBA

TRACK
ORIENTATION
P6TO
WRITE PCBA

I 0",,""

.1••2••3• •\\5}.6• •7••8.;.

TVFAVLTA*

R1 R4 R7 R10 R13 R16 A19 A22 R25
A2 A5 RS A11 R14 R17 R20 R23 R26

U10

c::::J r==J c:::::J

<$><s>
<8><s><B>
<S><S> <8>

_ _L--<B>_Tl______

READ HEAD
CONNECTOR

Figure 3-2

WRITE HEAD
CONNECTOR

GCR/PE Preamp 1 PCBA Test Points

11- TV CMD did not load
correctly to set drive
density
12 -

TV CMD did not load
correctly to start tape
motion to write BOT ID
Burst

*The interrupt code is used for non data transfer or data
transfer.

CHECKS AND ADJUSTMENTS

TROUBLESHOOTING

Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
B-

14-

TU CMD did not load
correctly to backup tape
to BOT after failing to
write BOT ID

COMMAND
PARITY

15 -

Failed to write ARA
Burst correctly

16 -

Failed to write ARA ID
correctly

TEST

'AOR

Failed to write density
ID Burst correctly

OJ ill CO CO

Mg'

935674
READ

PEGArN

R906~Rl06

~~~

17 -

ARA error bit set in
MTA status B register

21 -

Could not find a ga·p
after the ID code was
written correctly

22-

TU CMD did not load
correctly to start tape
motion to read ID Burst

23 -

Time-out looking for
BOT after detecting
ARA ID burst

24-

Failed to write tape
mark correctly

25 -

Tape never came up to
speed while trying to
reposition for retry of
writing tape mark

26-

TU CMD did not load
correctly to start tape
motion in Erase Gap
routine

27 -

Could not detect a gap
in Erase Gap routine

30-

Could not detect a gap
after writing record

(GCR PE

PEDESTALl

STEP)

STEP TIME)

[Sl1==?
"'79
+5.1SV

III

Figure 3-1

TU78 Card Cage Showing Maintenance
Switches and Adjustment

CHECKS AND ADJUSTMENTS

TROUBLESHOOTING
Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

Failure Code
31 -

Read path terminated
before entire record was
written

32 -

Could not find a gap
after writing record and
read path terminated
early

33 -

TU CMD did not load
correctly to backup for
retry of write tape mark

34 -

TU velocity changed
after up to speed while
trying to reposition for
retry of writing tape
mark

35 -

TU CMD did not load
correctly to backup to
retry a read of BOT ID

36 -

Time-out looking for
BOT after failing to
write BOT ID

37 -

TU velocity changed
while writing PE gap
before starting to write
record

40 -

TU CMD did not load
correctly to set PE
tape density at start of
write BOT ID burst

41 -

TU CMD did not load
correctly to set GCR
tape density after
writing Density ID

42 -

TU CMD did not load
correctly to set PE tape
density at start of read
from BOT

-0
.0_
<:1:1

E-<or.

+1
U

"t:l

>
or.

+1
U

"t:l

>
or.

Table 2-4

Interrupt Code to Failure Code (Cont)

Int
Code Name

CHECKS AND ADJUSTMENTS

TROUBLESHOOTING

TMFAVLTBt

Failure Code
43 -

TV CMD did not load
correctly to set GCR
tape density after
reading a GCR Density
ID burst

00 -

RSTO interrupt occurred
with TM RDY still set
(ACjDC LO)

01 -

Power failed interrupt

02 -

Interrupt for unknown
reason on channel 5.5

03 -

Interrupt for unknown
reason on channel 6.5

04 -

Interrupt for unknown
reason on channel 7

05 -

Interrupt for unknown
reason on channel 7.5

06 -

CAS contention retry
count expired

07 -

CAS contention error not
retryable

10 -

Queue error; could not
find queue entry

II -

Queue entry already full

12 -

8085 ROM parity error

13 -

In-line test 0;
WMC self test failed =
M8959-M8957

14 -

In-line test I;
XMC ROM parity error
M8958-M8959-M8960

15 -

In-line test 2;
RPM self-test failed
M8953-M8960

CHECKS AND ADJUSTMENTS

TROUB LESHOOTI NG

Table 2-4 Interrupt Code to Failure Code (Cont)
Int
Code Name

==-=
5 '"
_~

100

= '"
-=
<Q..'"

"-.100

t')

"<T

\Ci

.,.;

= 00£)
~<
~

.§

t:~

= -CQ
gu

:;'

Failure Code
16 -

In-line test 3;
RPM1 channel 0 self-test
failure M8950 (slot ABl2)

17 -

In-line test 4;
RPM1 channell self-test
failure M8950 (slot ABl3)

20-

In-line test 5;
RPM1 channel 2 self-test
failure M8950 (slot AB14)

21-

In-line test 6;
RPM 1 channel 3 self-test
failure M8950 (slot AB 15)

22-

In-line test 7;
RPM1 channel 4 self-test
failure M8950 (slot AB16)

23-

In-line test 10;
RPM1 channel 5 self-test
failure M8950 (slot CDl3)

24-

In-line test 11;
RPM 1 channel 6 self-test
failure M8950 (slot CD14)

25 -

In-line test 12;
RPM1 channel 7 self-test
failure M8950 (slot CD15)

26-

In-line test 13;
RPM1 channel P self-test
failure M8950 (slot CD16)

27 -

In-line test 14; RPM 1
error correction
self-test
M8950-M8951-M8953

30-

In-line test 15; 40000 40777 RAM memory
failure M8960

"<T

.,.;

M
..f

0;;
t:~

-CQ

"S
Q..

;;
~

Eo-

-=
=

e<£

-;= Col
~

'"
&;:

&;:=

Col

"c:i
00

=
~

e-e~~

O£)~~"<T

+10 E-o ~

~l'"

,-,t:]C

"c:i Eo-

e-~ ~ =

1-=
00 ;

E~~-g

~~~ ~

i<£

~
Eo-

~CQ~_u~O'I
+1 ~ Eo- ~

..c

'-'>"OE-o

Elooc'-' +"'''0
o =
e-.:~-g
.2g
0
~ e
~5.
- ~ E-o
100

0
00 0

100

.§
~

:;'

~
~

Eo-

100

~
~

Q..''""
100

~"O

0
0

-g;~
100

>'0.
~

= 0
00_

]"00
100

0. 0
=0.

o ~
~-o
~

E-o..9

] §
Q) ~.;:

0.'-

~8.

~
100

'" I
~

:l:The interrupt code is used for TM78 initiated.

§ The interrupt code is used for data transfer.

TROUBLESHOOTING

CHECKS AND ADJUSTMENTS

Table 2-4 Interrupt Code to Failure Code (Cont)
Int
Code Name

Failure Code
31 -

In-line test 16; 4100041777 RAM memory
failure M8960

32 -

In-line test 17; 42000 42777 RAM memory
failure M8960

33 -

In-line test 20; 4300043777 RAM memory
failure M8960

34 -

In-line test 21; 44000 44777 RAM memory
failure M8960

35 -

In-line test 22; 4500045777 RAM memory
failure M8960

36 -

In-line test 23; 46000 46777 RAM memory
failure M8960

37 -

In-line test 24; 4700047777 RAM memory
failure M8960

40 -

In-line test 25; loop
write-ta-read at TV port
O-GCR

41 -

In-line test 26; loop
write-ta-read at TV port

O-PE
42 -

In-line test 27; loop
write-to-read at TV port
I-GCR

43 -

In-line test 30; loop
write-ta-read at TV port

I-PE
44 -

In-line test 31; loop
write-ta-read at TV port
2-GCR

'o.g
..c::
c_

.og e
I!.>

.... >.
0
... Q.

Z ~

TROUBLESHOOTING

CHECKS AND ADJUSTMENTS

Table 2-4 Interrupt Code to Failure Code (Cont)
Int
Code Name

Failure Code
45 -

In-line test 32; loop
write-ta-read at TV port

2-PE
46 -

In-line test 33; loop
write-ta-read at TV port

3-GCR
47 -

In-line test 34; loop
write-ta-read at TV port

3-PE
50 -

In-line test 35; loop
write-ta-read at MTA 0 -

GCR
51 -

In-line test 36; loop
write-ta-read at MTA

O-PE
52 -

In-line test 37; loop
write-ta-read at MTA

I-GCR
53 -

In-line test 40; loop
write-ta-read at MTA

I-PE
54 -

In-line test 41; loop
write-ta-read at MT A

2-GCR
55 -

In-line test 42; loop
write-ta-read at MTA

2-PE
56 -

In-line test 43; loop
write-ta-read at MTA

3-GCR
57 -

In-line test 44; loop
write-ta-read at MTA

3-PE

TROUBLESHOOTING

CHECKS AND ADJUSTMENTS

Table 2-4 Interrupt Code to Failure Code (Cont)
Int
Code Name
34

MBFAULT

KEY FAIL

Failure Code
01 -

Control bus parity error
(Write)

02 -

Illegal MASSBUS register
referenced

01 -

Keypad entry error

02 -

TM78 not off-line

03 -

Illegal instruction code

2.7 TM78 MAINTENANCE PANEL
A firmware driven TM78 maintenance panel provides
access to the operational microcode functions, internal
hardware registers, and the resident microdiagnostics.
A table of instructions may be created in RAM
through the keypad to exercise the formatter or a single
tape transport. Many functions of the maintenance panel
can be used while the TM78 is on-line and performing
tape operations for a host CPU. Added maintenance
functions are provided when the TM78 is switched offline from the host.
NOTE
Because the operational microcode must timeshare or interleave the host commands and the
maintenance commands, use of the keypad
while on-line causes slower response time to the
commands issued by the host. Therefore, be
sure to check with the system operator before
using the maintenance panel to see if this latency is acceptable. If not, use the instruction
delay in parameter item No.2 (Table 2-6).
The maintenance panel includes a 20-key keypad and
a 6-digit octal display cluster. Figure 2-1 shows a detailed view of the maintenance panel.
2.7.1 Keypad Function Summary
The following is a summary of the keypad functions.

TROUBLESHOOTING

CHECKS AND ADJUSTMENTS
TEN THOUSANDS

HUNDREDS

UNITS (LSD)

00000
00000
00000
00000

Figure 2-1

TM78 Maintenance Panel

Miscellaneous Keys

ENA

Pressing this key once enables
the keypad. Pressing this key
again disables the keypad.

CLR

CLEAR erases a number in the
display and stops a looping command.

"0"0

trl trl

..no
++1

Numeric Keys
The eight numeric keys specify
one of the following before a control or operation key is pressed.
Memory address
Memory data
Internal I/0 hardware address
Internal I/O hardware data
Parameter item number
Parameter data
Instruction item number
Instruction op-code

TROUB LESHOOTI NG

Control Keys
INS

HDW

PAR

CHECKS AND ADJUSTMENTS
Table 3-1

The INSTRUCTION key is
used to examine and modify any
of the sixteen instruction locations.
The HARDWARE key is used
to examine and modify most of
the 377 TM78 internal I/O registers. (Appendix B of the TM78
Technical Manual.)
The PARAMETER key is used
to examine and modify the set of
parameter items that control the
microcode in performing maintenance functions.

MEM

The MEMORY key is used to
examine and modify locations
within the microcomputers memory space.

NXT

The NEXT key causes the next
sequential item or location of the
group (INS, HDW, PAR, or
MEM) selected last to be examined.

DEP

The DEPOSIT key is used to
modify the contents of an item or
location.

Operation Keys

EXE

The EXECUTE key is used to
execute a single maintenance instruction one time only.

REP

The REPEAT key causes a
single maintenance instruction
code to be executed repeatedly.

STA

The START key initiates the execution of instructions previously
deposited into the instruction
item group.

Checks/Adjustments When Replacing Parts (Cont)

Part
Replaced

Check or
Adjustment

Maintenance
panel

Keypad/
display power
on checks

3.5.1.1 *

H7441

+5V

5.7.5t

H7446

±15 V

5.7.5t

H7490

-5V

5.7.5t

Paragraph

NOTE
The paragraph number listed is for the full procedure
found in the applicable technical manual.
*TU78 Technical Manual (Vol II)
tTM78 Technical Manual

CHECKS AND ADJUSTMENTS

Table 3-1

TROUBLESHOOTING

Checks/Adjustments When Replacing Parts (Cont)

Part
Replaced

Check or
Adjustment

Takeup
reel
motor

Takeup reel
load speed
Tape loop
position

6.5.6.3*

AC motor

Vacuum/
pressure

6.5.4*

Blower

System
vacuum
Takeup reel
vacuum

6.5.4.1 *

Air bearing
pressure
Thread block
and cartridge
pressure

6.5.4.3*
6.5.4.4*

Read PCBA

PE gain

Write
PCBA

Write
currents
PE gain

Compressor

Capstan
Servo
PCBA

Power
Capstan
servo
adjustments
PE gain

Reel
servo
PCBA

Reel servo
adjustments
Dynamic
brake check

Preamp
PCBA

PE gain

Interconnect
FIPCBA

EaT/BOT
sensor
Pack sense
sensor
Tape loop
position

The CONTINUE key may be
used to continue the maintenance instruction program at the
item number saved when it was
last stopped.

CON

Paragraph

6.5.6.4*

6.5.4.2*

2.7.2 Errors
An error code is displayed whenever a command cannot be performed. Table 2-5 lists all the error codes and
the reason for the error.
Table 2-5
Code in
Display

Keypad ErrorfStatus Codes

Meaning

EOOI

Value of item number or location is too large for
this group.

E002

Value of item number or location is already at
high limit when NXT key was pressed.

6.5.7.3*

EOO3

No numeric value was specified before deposit.

6.5.7.2*

E004

Privileged function is requested (such as
modifying a RAM or hardware location) with
TM78 on-line.

E005

ROM address is not in use.

E006

Illegal instruction code is selected for an
instruction item.

77 -01

Error is detected when attempting to execute a
maintenance instruction to a TU78. Either the
TU78 selected by parameter item 0 is not in
maintenance mode (port select 3), or the
adjustment selected is out of acceptable
tolerance.

77 -02

Privileged maintenance instruction is requested
with TM78 on-line.

77-03

Illegal instruction code is specified when using
EXE or REP keys.

6.5.7.3*
6.5.1 *
6.5.5*

6.5.7.3*
6.5.6*
6.6.6.1 *

6.5.7.3*

6.5.2*
6.5.3*
6.5.6.4*

TROUBLESHOOTING

2.7.3 Parameters
Table 2-6 lists each parameter location and a description of how it conditions or affects the hardware when
running maintenance panel instructions.
Table 2-6

Parameter Items

Read/
Item
Number Write

R/W

Initialized
Value
Description
000

MASS BUS Port/Tape unit
port select
This item selects one of
two MASS BUS ports and one
of four Tape unit ports
to communicate with.

Bit

Value

Port
Selected

7
7
1:0
1:0
1:0
1:0

0
1
0
1
2
3

MASSBUSA
MASSBUSB
TU PortO
TU Port 1
TU Port 2
TU Port 3

This item corresponds to
hardware register 340-W.
R/W

000

Program run control
This item is used by the
STA and CON keys. When
this item is any number
other than 0, a program
can be single-stepped one
instruction at a time.
When this item is 0 the
program can run.

CHECKS AND
ADJUSTMENTS

R/W

000

Instruction delay
This item is used to insert a
delay between each instruction
pass when in LOOP mode. The
larger the number the longer the

3.1 PARTS REPLACEMENT
Table 3-1 lists the corequisite check or adjustment
that must be made when replacing certain parts in the
subsystem. If a part is not listed in the table, then no corresponding check or adjustment is required.
3.2 QUICK REFERENCE ADJUSTMENT
SPECIFICATION
Table 3-2 provides a quick reference to the various
TM78/TU78 adjustment specifications. Figure 3-1, 3-2
and 3-3 show the location of various controls and switches on the TU78 PCBAs. Figure 3-4 shows the air valves
with their test points and adjustments.
Table 3-1

Checks/ Adjustments When Replacing Parts

Part
Replaced

Check or
Adjustment

Read/
write/
erase
head

Clean
transport
Power
Capstan
servo
adjustment
Read/write
adjustments

4.3.4*

System
vacuum
Takeup reel
vacuum
Read skew

6.5.4.1 *

Capstan
motor

Supply
reel
motor

Supply reel
load speed
Tape loop
position

Paragraph

6.5.1 *
6.5.5*

6.5.7*

6.5.4.2*
6.5.7.1 *
6.5.6.2*
6.5.6.4*

*TU78 Technical Manual (Vol II)

TROUBLESHOOTING

Interconnect Fl PCBA

Table 2-6

TP 1 spas
TP 2 T pas 2
TP 3 TIP
TP 4 N PKSN
TP 5 EaT
TP 6 BOT
TP 7 GND

Item
Read/
Number Write

Reel Servo PCBA

TP 1
TP 2
TP 4 +36 V (T)
TP 6 TM (+)
TP 8 TM (-)
TPI0 -36 V (T)
TP12 +36 V (S)
TP14 SM (-)
TP16 SM (+)
TP18 -36 V (S)
TP20 UNUSED
TP21 NTDA
TP22 NTDB
TP23 NSDA
TP24 NSDB
TP49 GND
TP50 GND
TP51 Q2 (CaLL)
TP52 REEL SERVO BRAKE
TP 53 +5 V (S) TO ALL IC'S
TP54 UNUSED
TP55 TPOS
TP56 NTRRTP57 NTRF
TP58 SUM AMP OUT NDTA/B
TP59 SUM AMP OUT T IU LOOP CaMP
TP60 NAE (REEL SERVO ENAB)
TP61 NTINTLK
TP62 +15 v DC
TP63 UNUSED
TP64 -15 V DC
TP65 1.25 KHZ T-WAVE GEN
TP66 spas
TP67 OFFSET
TP68 SUM AMP OUT SUP LOOP CaMP
TP69 NSRF 1
TP70 NSRR
TP71 SUM AMP OUT NSDA/B
TP72 NSRF 2

Parameter Items (Cont)
Initialized
Description
Value
delay. The delay can be used to
reduce the impact on host CPU
throughput, to allow tape to
stop between instructions, etc.

RjW

000

General-Purpose counter
This counter can be
loaded, counted, and
tested by maintenance
instructions.

000

Branch status
Status byte returned by
all instructions. Used
by conditional branch
instructions.
Bit 0 - error
Bit 1 - end of tape
Bit 2 - tape mark

000

Interrupt code
(Table 2-5)

000

Failure code (Table 2-5)
I terns 5 and 6 contain the
execute status returned
by the last tape command
or in-line diagnostic
control instruction.
Program control and
privileged instructions
return execute status but
do not write into these
parameter items. These
items make it possible
to run a program that
performs tape commands
and halts if an error is
detected. The actual
error can be identified
by examining these
parameter items after
the program halts.

TROUBLESHOOTING

Table 2-6

Parameter Items (Cont)

Item
Read/
Number Write
7

TROUBLESHOOTING

TP21 CLEAR
TP22 ST 1 CLOCKS
TP23 UNUSED
TP24 UNUSED

Initialized
Value
Description
000

Program continue
address
The CON key uses this
item to determine next
instruction address.

R/W

In-line diagnostic
index
This item selects an
in-line diagnostic
program for maintenance
instruction 16. Refer to
Table 2-2 for a listing
of the in-line tests
available.

R/W

120

Data format and skip
count
Data transfer maintenance
instructions uses this
item and corresponds to
hardware register 32O-W.
Initialized to image
format with a zero skip
count.

Bit Value Description
7
6:4
0
I
2

3
4
5

6
7

Not used
Format Control
II normal
15 normal
10 compatible
10 core dump
10 high-density
compatible
Image (skip count
has no effect)
10 high-density
dump
Illegal

Write PCBA
TP 1 CLK 2
TP 2 V PED
TP 3 V STEP
TP 4 V WRT
TP 5 CLK 1
TP 6 V PED AT Q27/28 WD2
TP 7-23 UNUSED
TP24 REWR (REWIND RAMP)
Capstan/Regulator PCBA
TP 1 GND
TP 2 GND
TP 3-10 UNUSED
TPII +5 V DC
TP12 V SENSE
TP13 MOTOR CURRENT
TP14 UNUSED
TP15 +15 VDC
TP16 UNUSED
TP17 UNUSED
TP18 -15 VDC
TP19 MOTOR VOLTAGE
TP20-24 UNUSED
TP49 CAPSTAN GND
TP50 CAPSTAN GND
TP51 NFPT
TP52 ANALOG TACH
TP53 UNUSED
TP54 UNUSED
TP55 SPARES 1
TP56 CART SOL RET
TP57 VAC SOL RET
TP58 WP SOL RET
TP59 PRES SOL RET
TP60-64 UNUSED
TP65 8.5 VAC
TP66-69 UNUSED
TP70 NPORST
TP71 CART MTR (+)
TP72 UNUSED

TROUBLESHOOTING

Parameter Items (Cont)

Control M2 PCBA

Table 2-6

TP35 - LDF 3
TP36 - NBOT
TP37 - STL
TP38 - NEOT
TP39 - CLK C (10 KHZ)
TP40 - TACH AMP
TP4l - LDF 5
TP42 - LDF4
TP43 - LOW TAPE SENSOR
TP44 - NLDFS
TP45 - LDS (LOAD FAULT SENSE)
TP46 - BKW
TP47 - MRL
TP48 - ABP N/O
TP49 - GND
TP50 - GND
TP51 - NPOL
TP53 - THD
TP54 - CC N/O
TP55 - CO N/O
TP56 - U146-5 UNLD
TP57 - S LIMIT N/O
TP58 - NSMRL
TP59 - TOR N/O
TP60 - VAC N/O
TP61 - T LIMIT N/O
TP62 - NINTLK
TP63 - NCCC (CLOSE CART CMD)
TP64 - SRF
TP65 - SRR
TP66 - TRF
TP67 - TRR
TP68 - THDS
TP69 - NCOC (CART OPEN CMD)
TP70 - NRSAE (REEL SERVO ENABLE)
TP71 - PNU RET
TP72 - NXFR

Item
Read/
Number Write

Read PCBA
TP 1
TP 2
TP 3-9 UNUSED
TPI0 TRK 9/0 ACTIVE (CH4 & 6)
TPll TRK 9/1 ACTIVE (CH4 & 5)
TP12-19 UNUSED
TP20 U29-11

Initialized
Value
Description
3:0
00
01
02
03
04
05
06
07

•

11-17

Skip Count
No skip
Skip 1 byte
Skip 2 bytes
Skip 3 bytes
Skip 4 bytes
Skip 5 bytes
Skip 6 bytes
Skip 7 bytes
Skip 8 bytes
Illegal

R/W

020

Write function clock
control

R/W

022

Read GCR function clock
control

R/W

023

Read PE function clock
control

R/W

020

LOOP write to read
function clock control
Items 12 - 15 are the
data loaded into the
clock control register
before the function is
performed. Refer to
hardware register 360-W
in TM78 Technical Manual
for a description of the
bit combinations.

R/W

005000

Write record size
This 16-bit item is the
byte count used by write
data maintenance instructions to determine the
size of the record
written. It is used by
read data maintenance
instructions as the
expected record size.

*ltem value is not initialized by enabling keypad.

TROUBLESHOOTING

Table 2-6

Parameter Items (Cont)

Read/
Item
Number Write
17

TROUBLESHOOTING

Initialized
Value
Description

000000

Read record size
This I6-bit item is
returned by read data
instructions as actual
size of record read.

R/W

777777

Write data
This I8-bit item is
written into the DDR for
write data instructions.

000000

Read data
This I8-bit item contains
the contents of the DDR
after the last read data
instruction, if performed
in image format. It is
cleared on every read in
all other formats.

Last fatal interrupt code
for port A
Last fatal interrupt code
for port B
I tern 23 and 24 are a
history of last fatal
interrupt code (right
justified).

Last fatal failure code
for port A

Last fatal failure code
for port B
Items 23 and 24 are a
history of the last fatal
failure code (left
justified).

Figure 2-2

Sample Write/Read Routine

Control M2 PCBA
TPI9 - CLK E (10 HZ)
TP20 - CLK A (1 MHZ)
TP22 - U71-6 CAPSTAN REV
TP23 - U63-6
TP24 - U66-6 NRD'Y
TP25 - GND
TP26 - GND
TP27 - LDF I
TP28 - LDF 6
TP29 - U72-11 RWS
TP30 - MAINT FUNCTION
TP31 - MAINT FUNCTION
TP32 - LDF 2
TP33 - NTAP 2
TP34 - N>80 %

TROUBLESHOOTING

2.7.5 Sample Maintenance Routine
Figure 2-2 shows the program flow for a sample
write/read maintenance routine. This routine writes a record, reads it backward and forward, then repeats the
operation till the EOT marker is reached where the tape
is rewound. A tally of all read errors is put into the display for each tape pass. If a write error occurs, many important TM78/TU78 registers are saved in parameter locations. Then the program halts so that these parameters
can be analyzed.
The program coding is shown below.
Instruction
Address

Instruction
Code
Description

0
1
2
3
4
5
6

7
100
61 (63)
240
214
77
211

7
10

71
222
4
12
362
10
2
362

12
13

14
15
16
17

Rewind tape
Clear counter
Write PE (GCR)
If EOT, branch to start
If error, branch to save
Read reverse
If error, branch to count
update
Read forward
Branch to write if no error
Increment counter + 1
Put count in display
Branch to write
Save registers
Halt
Branch to write after continue

2.8 TEST POINTS
The following list includes all troubleshooting test
points available on the TU78 PCBAs and the corresponding signal name.
Control M2 PCBA
TP 1 - GND
TP 2 - GND
TP 3-12 - UNUSED
TPI3-+5VDC
TP14 - LDFO
TP15 - CLK B (l00 KHZ)
TPl6 - U85-2
TP17 - UNUSED
TPl8 - NLDPI

TROUBLESHOOTING

Table 2-6

Parameter Items (Cont)

Item
Read/
Number Write

•

Initialized
Value
Description

The remaining items are stored whenever the execution of a
tape unit operation results in an error. The error status in the
hardware registers is saved so that it can be interrogated by
maintenance personnel. A copy of these items exists for each
tape unit and is readable by the host CPU EXT SENSE
command.
26

Command code is being
executed on last error.

Interrupt code is 6 bits
right justified.

Failure code is 6 bits
right justified.

NOTE
Items 26 through 30 are written with zeros when
these locations are written as a result of the keypad
hardware dump instruction.
Items 31 -105 are
hardware registers.
Register
31

33
34
35
36
37
40
41
42
43
44
45
46
47
50
51

R
R
R
R
R
R
R
R
R
R
R
R
R
R
R

*
*
*
*
*
*
*
*
*
*
*
*
*
*
*

2
3
20
21
22
23
24
25
26
27
30
31
32
40
41

Contents
Read path write
fail bits
Read path
diagnostic bits
Read path status
Read path CMD
AMTIE
RC done
Illegal 5-4/
Mark 2
End mark
RC par bits
Postamble det
Data
CRC
Corrected data
ECC status
Channel 0 TIE bus
Channell TIE bus

*Item value is not initialized by enabling keypad.

TROUBLESHOOTING

Table 2-6

TROUBLESHOOTING

Table 2-7

Parameter Items (Cont)

Item
Read/
Number Write

Initialized
Description
Value

Instruction
Code

52
53
54
55
56
57
60
61
62
63
64
65
66
67
70
71

*
*
*
*
*
*
*
*
*
*

114
240
241
300
320
321
322
323
324
324
325
325
326

Channel 2 TIE bus
Channel 3 TIE bus
Channel 4 TIE bus
Channel 5 TIE bus
Channel 6 TIE bus
Channel 7 TIE bus
Channel P TIE bus
TIE bus
AMTIE
Port Status
Read data
CAS status
CBUS status
DBUS status
WMC status
TU select 0
TU select 1
Write data
Byte counter <7:0>
Byte counter < 15:8>
Pad counter <7:0>
Pad Counter <15:8>
Ecode counter

326

Ecode counter

R
R
R
R
R
R
R
R
R
R
R

*
*
*
*
*
*
*
*
*
*
*

330
331
332
340
0
1
3
4
4
5

DDR/MBDA.
DDR/MBDB.
WMC Errors
Interrupt status
MIA status
MIA status A
MIA status B
Serial NRA
Serial NR B
TU diagnostics
Retry counter

*
*
*
*
*
*
*
*
*
*

100

R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R

101
102
103
104
105
106
107
110

73
74
75
76
77

III

112
113
114

42
43
44
45
46
47
50
60
104
110

<7:0>
<15:8>

This item count of number
of retry requests given.
A zero means tape unit is
not in error recovery.

115

Retry control bits

•

Maintenance Instruction Codes (Cont)

Description

Controlling
Parameter Items
(Table 2-6)

In-Line Diagnostic Control Instructions

Run in-line
diagnostic
(Table 2-2)
Run tape speed
adjustment routine
Run start ramp
adjustment routine
Run forward stop
ramp adjustment
routine
Run reverse stop
ramp adjustment
routine
Write 13 mm
(0.5 in) record
pattern generator
-PE
Write 13 mm
(0.5 in) record
using pattern
generator - GCR

32
34
36
40
42

26
30
46
50

1,10,15

1,3,12,147

Privileged Instructions (TM78 must be off-line)
Write continuously
at 3200 FRPI in
all tracks
Write continuously
at 9042 FRPI in
all tracks
Write continuously
using pattern
generator - PE
Write continuously
using pattern
generator - GCR

0,12
0,12
0,3,12,147
0,3,12,147

TROUB LESHOOTI NG

TROUBLESHOOTING

Table 2-7

Maintenance Instruction Codes (Cont)

Instruction
Code

Description

Controlling
Parameter Items
(Table 2-6)

61
63
71
77

Write data - PE
Write data - GCR
Read forward
Read reverse

0,1,11,12,16,20
0,1,11,12,16,20
0,1,11,13,14,17,21
0,1,11,13,14,17,21

Program Control Instructions (Do Not Use with EXEjREP
Keys)
0
2
4
6
10

12
14

100 + n
200 + x
220 + x
240 + x
260 + x
300 + x
320 + x
340 + x
360 + x

NO-OP
Halt
Increment
counter + 1
Decrement
counter + 1
Update parameter
items 26 through
157 with current
hardware status
Display contents
of counter.
Display contents
of parameter item
addressed by
counter.
Load counter
with n
(n = 0-77)
Branch if error
status
Branch if no error
status
Branch if EOT
detected
Branch if no EOT
detected
Branch if tape
mark detected
Branch if no tape
mark detected
Branch if counter
not zero
Unconditional
branch

Table 2-6

Parameter Items (Cont)

Readj
Item
Number Write

Initialized
Description
Value

Bit 5 - initial command
moved tape in reverse
Bit 6 - initial command
was a read
Bit 7 -last retry
requested was in opposite
direction of initial
command

•

1
7
1,3

116

TU software status
Bit 0 - DSE command in
progress
Bit 1 - rewinding
command in progress
Bit 2 - tape unit exists
Bit 3 - motion command
(NDT) in progress
Bit 4 - moved in reverse
direction last
Bit 5 -last operation
wrote on tape
Bit 6 -last record seen
was tape mark
Bit 7 - Massbus port B
issued last command

1,3
0,1

1,3
1,3

1,3
117

Transfer control word

1,4
This item is the control
word for last data
transfer command

1,4
1,4

Bits 0-2 - write clock
select
Bits 3-5 - read clock
select
Bits 6 - PLO bypass
Bit 7 - low read
threshold

1,4
1,4
(\'~

1,4

••

1,3

x = Item number (0 to 17) of next instruction if branch condition is true

120

Retry suppress and format
control

*ltem value is not initialized by enabling keypad.

Table 2-6

Parameter Items (Cont)

Readj
Item
Number Write

Initialized
Value

Description
This item is a copy of
Massbus register
containing retry
suppress, format and skip
count.

121

TROUB LESHOOTI NG

TROUBLESHOOTING

,
I

•

Keypad enable flag
This item is nonzero when
keypad is enabled.

Table 2-7

140

140
141

W
R

*
*

141
142

W
R

*
*

142

143

143
144

W
R

*
*

144
145

W
R

145
146
147

150157

2.7.4 Maintenance Instructions
A table of 16 maintenance instructions may be assembled and run using the INS, STA and CON keys. Single
instructions may also be executed with the EXE and
REP keys. The transport being exercised must be selected to port #3. Table 2-7 lists all available maintenance instruction codes, their description, and the parameter item codes that influence the execution of that
instruction. Tape Command (Group A), Program Control (Group B), and In-Line diagnostic control instructions (Group C) may all be run while the TM78 is offline or on-line with the host CPU using another transport. However, privileged instructions (Group D) require
that both ports of the TM78 be placed off-line.

Not used

122137

RjW

MIA register 0, TV78
status
MIA register 0, TV CMD A
MIA register 1, MIA
status a
MIA register 1, TV CMD B
MIA register 2, MIA
status b
MIA register 2, AMTIE
loop
MIA register 3, serial
No. a
MIA register 3, threshold
MIA register 4, serial
No.B
Not used
MIA register 5, TV
diagnostics
Not used
Not used
MIA register 7, pattern
generator data
Not used
Items 140 - 147 are
explained in Appendix C
of the Technical Manuals.

*ltem value is not initialized by enabling keypad.

Instruction
Code

Description

Tape Commands (NonpriviJeged)

Rewind and
unload tape
Rewind tape
Write tape
mark- PE
Write tape
mark-GCR
Space one
record forward
Space one
record reverse
Space forward one
record or file
Space reverse one
record or file
Erase extended
gap-PE
Erase extended
gap-GCR
Loop write-to-read
at TV port - PE
Loop write-to-read
at TV port - GCR
Loop write-to-read
at MIA
Loop write-to-read
at MIA PCBA - GCR

17
21
23
31
33
35

.'-,

Maintenance Instruction Codes

7
15

51
53
55
57

Controlling
Parameter Items
(Table 2-6)

0,1
0,1
0,1,12
0,1,12
0,1,13,14
0,1,13,14
0,1,13,14
0,1,13,14
0,1
0,1
0,1,15
0,1,15
0,1,15
0,1,15

rr~S;C;T- - - -

REMOTE
SWITCHING
CONTROL BUS
FROM CPU

-- -- -

-- -

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

I TU78-0

--1

(POWER ON/OFF)

SUPPLY SERVO FEEDBACK

INPUT POWER

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

I
I

I
I
I
I
I
I

~CONTROL

v•

BUS

_ _ _ ~~~TE

L_________________ ~T~

I
I

MIA

CONTROL
LOG IC & I---:=-:-::--=""=---t
MANUAL

CONTROLS~~~~~~~~~~~~
____-t~~~~~~l
AUTOLOAD
MOTION
COMMANDS

I
I

MOTION
COMMANDS

I
I

SUPPLY LOOP
PNEUMATIC
COLUMN
(BUFFER BOX)

L ______ _

TACHOMETER OUTPUT
PNEUMATIC COLUMN
(BUFFER BOX)

, - - - - - - - AC LINE

FROM COMPRESSOR

____ J

TU78 Subsystem Detailed Block Diagram

WRITE

peBA

PCBA

ON READ PCB
(PREAMP OUTPUTI
P05

WRITE AMP

FIGURE 6-40
WAVEFORM

POINT

lB
15
20
21
22

38
39
40
41
42
43

23
24
25

J6
WRITE
AMP
OUTPUT

44
45
I
I

1-------115

~..",
I

PO
WRITE
CABLE

W07

HEAD
\
CENTERTAP
COMMON PIN

CENTER TAP
TO ONE LEG

= 3 n APPROX

1
23
1
23
1
23

23
23

WRITE AMP OUTPUT.!
TO WRITE HEAO /
)WD
PIN #S
7
6

5
4

3
2
I
0
P

15
21
I'
22
16
18
19
20
17

23 (P904)
CABLE HEADER
ON PREAMP PCB

CENTER TAP COMMON
TO ALL WRITE HEADS

12 }
CH7
3

WOP

~4 }CHP

W02

~5 }CH2

WOl

16 }
7
CHI

WOO

11
2 } CH5

~3 }CH3

HEAD

J904

W03

J6'

WRITE
STACK
CENTER TAP

W05

VWRT
IWRITE
CURRENT)

TRACK
CHAN, OUT
NO.
1

17 }

lB}

CHO
CH6

PINION PO (COMMONI
CENTERTAP TO PINS
2,3,4,5,14,15,16, 17

OUT
2

RIO
R13

Rll

R 16

R19

R22

R23

R25

RD
(POI

CONN,

COMMON
CENTER-TAP

\ ~----------~---------~~

12
13

12
14
29

I
I
I

32
21
30
27

20
26

P05 IPREAMP OUTPUT RD51

~~I~:"';;;"'--+---=-'--,=-----li U
PREAMP

OUTPUT

REAO
PCBA
J5 PIN"
51
52
53

PIN 23 (COMMONI
CENTERTAP TO PINS
6,7, B, 9, la, 18,19,20,21,22

:FP~?~PROX

/ :---

INTERCONNECT Dl

23
8

R14

68
67
62
61
59
58

READ PREAMP
CABLE
RIBBON CABLE

I
READ HEAD:

READ
PRE·AMP

READ PCBA

55
56
57
49

P5 TO BACKPLANE EDGE CONNECTOR
WCS TEST DATA
(FROM FORMATTER'

I
I
I
I
I

0~-----------------------

9
2
10
4
6
7
B

WD4

,I
I
,

~~-------------~ - - ~- --~-T -------~---- ~ -

STOTH

6J\

AMTIE

~ T:;"~~HOLD

~ NOT I
P7

AMTtE CABLE

USED,

IOF FRONT:
ON
WRITE I AMTIE

LEVEL
:.:.::c---!*H OET

GCR PE
(GAIN)
WRITE PCBA

FIGURE643,4.
WAVEFORM

I
I

ICClClO'CIClCl~OClI
10000000

co 01

20
;

I~~~TE

IJI MIA
AMTIE PIN Ii
1
19
2
20
3
12

I
11

,
:

AMTIE
CABLE

•

f---',--,~~I~
5

6
7

35
33
31
29
27
25
23

1::::::::::::::::::::1

J3PIN ~

1
2
3

4
3
e--~-.-..,.;2~

W
mi

/Pl

e---,,-+--,,13"----!

Read Path Troubleshooting Diagram

MIA
PCBA

PCB)ICABLE

ru
!

I
,

J25 IONI P25

NLTH

Write Path Troubleshooting Diagram

------1

PATH

13
15
17
19

MIA