Tektronix 4112 User manual

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TEK
SERVICE MANUAL
VOLUME 1
First Printing SEP 1982
4112
Part No. 070-381 7-00
Product Group 16
COMPUTER DISPLAY
TERMINAL
Please Check for
CHANGE INFORMATION
at the Rear of this Manual
I.
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WARNING I
THE FOLLOWING SERVICING INSTRUCTIONS ARE
FOR USE BY QUALIFIED PERSONNEL ONLY. TO
AVOID PERSONAL INJURY, DO NOT PERFORM ANY
SERVICING OTHER THAN THAT CONTAINED IN
OPERATING INSTRUCTIONS UNLESS YOU ARE
QUALIFIED TO DO SO.
Cooynght ~ 1982 bv Tektronil(, Inc . Beaverton O· ~ gon
Prin ted m tr.e Un i ted States of America A ll ri ghts reser .. ed
Contents of this pub llc atton may not be reproduce d m a ny
form w ithout perm i ss ion of Tektronix . Inc
This in strume nt . m w hole or 1n part. may be protected by one
or more U.S or foreign patents or pa te nt applications
ln lorma tton prov i ded on reQuest by Tek tr on ix. Inc . P0 Box
500 .Beaverton, Ore g on 97077
TEKTRONIX Is a registered tr ad emark of Tektronix . Inc .
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MANUAL REVISION STATUS
PRODUCT: 4112 COMPUTER DISPLAY TERMINAL
This manual suppcrts the following versions of this produc t: Ser ial Numbers 8010 1 00 and up .
REV DATE DESCRIPTION
SEPT 1 982
Ori\:linal I ssue ; replaces 061 -2 490 -00.
4112 SERVICE (VOLUME 1)

• CONTENTS
Section 1 INTRODUCTION Page
About T his Manual ......... ... ..... .•.. .... .. ... . ...... 1-1
Related Documents
.......... . .... . .. .. ... ....... . .. .. . .1-1
Insta
ll ation Information .................. .... .. ... ...... 1-2
General Description ........... . .......... . .. . ....... ... 1-2
Major Pa rts of the 4112 . .... . ....... . ..... .. ...... .. . 1-2
Front-Panel Controls and Indicato
rs ... . . ..... . ... .. .. 1-3
Rear-Panel Controls and Connectors
... . ... . ... .. . . .. 1 -4
Bell Indicator.. .. . .................. . .... . .. . .. ...... 1 -4
Error Messages .. . ...... .... ...... . ......... . ...... .. I -6
Options .. ................ .. .. ..... .... ... . .. ... .... ... . 1-7
Accessories ....................... ....... .. .... . ... ... . 1 -8
Standard Accessories. ........... ... . ... . ....... .. .. . 1-8
Optional Accessories . .. ... ..... .. . .... .. .. .. .... .. . . 1-8
Section 2 OPERATING INFORMATION
• Controls and Indicators
...... ... ....... ............. . .. . 2-1
Indicator
lights . .. ..... ... .. . .... .. ......... . .. . .. ... 2-3
Keyboard .. . ... ... . ...... . .... ... ...... . .... ... ... .. . 2-4
DisplayControl Keys and the Thumbwheels .......... . 2-5
Rear-Panel Controls and Connectors ..... . ....... ... . 2-6
Operating Check . ... . . ..... ... ... .. ... . .. .. .. ... . ... .. . 2-8
SETUP Mode .. ... .. ... .. ...... .. .......... . ...... . .. 2-8
SETUP Commands ... . ............................... 2-8
Using the Status Message .... .. ... . ..... . ........... . 2-9
Conventions .. . .... .. .... . ......... . .. ............... 2-9
4112 Startup . .. ......... . ..... . .............. .. .. .. . 2-10
Creatinga Graphics Segment ..... . .. ... . ............ 2-1 2
Manipulating a Graphics Segment
.... ... . .. .......... 2-14
GraphicsInput. .. . ... ... .. .. ... . ..................... 2-16
Section 3 CHARACTERISTICS
Characteristics/Specifications . ............. ...... .. .... 3-1
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112 SERVICE (VOLUME 1I ii

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Section 4 THEORY OVERVIEW
Defining Terms ... ...... ......... .. .... .. ............... 4-1
World Coordinate Space
.. ... ..... ........ ........ ... 4-1
Terminal Coordinate Space
.... ... .................... 4-1
Raster Memory Space
............ ............. ... .... 4 -1
The Window-V ie wport Transform . ... . .. . .. ..... ... .. . 4-2
Window
........... .. ...... ......... ... .. . ........... 4-3
Viewport ..... ......... ......................... .. .. . 4-3
General Display Concepts ...... .... .. ... . .............. 4-4
Pixels
....... . ............... ................ . ...... . 4-4
Characters ..
.... . ............ ............... ... .. .. .4 -5
Bit Map and Display Concepts ....... .. .. .. ...... ..... 4-5
4112 Overview ........... . ...... .. ........ ......... .. .. 4-6
Bus Masters and Slaves ............ ............. .. ... 4-6
Processor Bus ........ .... .. .... . ................ .. ..4-8
Display Bus
.......... ... ......................... .. . 4-11
VideoController. .
..................... .... ..... . .. 4-14
Vector Generator .......................... . ....... 4-14
Display Memories
................................. 4-1 4
Interfacing
....................... . ................ 4-1 4
Connectors
.......... . .... ........ .. ..... .. ...... . .. . 4-14
Section 5 PROCESSOR
BUS THEORY
Introduction to Processor Bus .............. ........ ..... 5-1
Processor Board Theory .
............................... 5-1
ProcessorTheory Overview
.......... . ............. .. 5- 1
Microprocessor{MPU) ......................... ... 5-3
InterruptContr oller ... ....... . ....... .. ..... ..... .. 5-3
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Processor Board to
Processor/System Bus Interface ...................... 5-3
System Memory .......... . ..................... . .. 5-3
Control, Status,and Timing ...... . .. .. ........ ..... 5-3
Host Computer Port .. ... . ...... . .. . ..... .. . ...... .5-4
Keyboard Port ..
.. . ................................ 5-4
Processor Board
Circuit BlockDescriptions
.................... . ..... .. 5-4
MPU ................. .. .................. ......... 5-6
The Bus Cycle
....... .......................... 5-6
MPU Internal States ............................ 5-6
Memory and 110 AddressSpace Access ......... 5-6
Resetand Initialization .................... ...... 5-8
Interrupt Operations
....................... . .... 5-8
Interrupt Controller ............... .. .. ...... ....... 5-8
Local Data Bus Buffer .......................... 5-8
InterruptPriority Logic and Registers
............ 5-8
Control Logic ................................... 5-9
Read and Write Log ic ............. .. ..... .. ..... 5-9
Cascade Buffers and Comparator ............... 5-9
PIC Operations ........... . ..... .. . ................ 5-1O
The InterruptOperating Sequence ............... 5-1O
1STINTA and Cascade Addresses
for Slave PlCs ..
... . ......... . .......... .. . ... .. 5-10
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411 2 SERVICE (VO LUME 1l

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Section 5 (cont)
Addr'ess Orrvers .............. . ... . ....... . . .... ... 5-10
Data Drivers/Receivers
.. . ......................... 5-10
Bus Command Dri
ve r .... . ... • ................ .. ... 5-1 1
Control Logic
.. . ..... .............. . ...... • ..... 5-11
MPU Status Decoder . . .. ... .. .. . .. .
........... 5-1 2
Control Signal Generator.
... .... .... . ......... ..5-12
Command Generator
...... ... .... .......... ... .. 5-12
ROM .. . ........ ...... .. ........•.. .... ..... . ... . 5-14
ROM Configuration
.. . .......................... 5-1 4
F
ir mware ... . •. .. .. . .. ... . .... . ............. . ... 5-14
Straps .... ... . .... . .. . ........ ...... . ...... .... 5-1 4
N
on -Volatile RAM .......... . .... .. .... .. ..... .. ... 5-15
Read Access. .
............................ .. ... 5 -1 6
Write Ac
cess .. .. . ...... . ............ . .......... 5-1 6
Microprocessor Control
...... . .... . ............... 5-16
Clock and Reset ............ . ..... . ........ .. ... 5-16
Ready Signa ls . .. .. . ..... . .... . ..... . ...... ... . . 5- 16
B us Transfer Log ic . .... .. ... . .. . .. .... .... . .. . ... . 5-1 7
End-of-Data-Transfer Strap
........ . .... ... .. ... 5-17
Address Decoding. ... .. .
.......... .. . ............ 5-18
Bus Timeout Detector .. . . ....... . .. .. ....... .. . ... 5-19
Status Input . .. .. ... ... . . ...... . ..... .... .. ... .... 5-19
Bus Clock Genera
tor .... ................ ... . ... .. . 5-19
MPU Timing Generator . ... ... ... .. .. ......... . .. .. 5-2 1
• Programmable Timerand Baud Rate Generator
..... 5-22
Programmable Interval Timer .... . .. .... . ........ 5-22
RS-232 State Change Detector .......... . ......... 5-23
RS -232 Communications Interface .......... ... .... 5-23
ProgrammableCommunications Interface
..... ... 5-23
MPU Control .. .. ... ...................... . .. . .. 5-25
Data Communication . ......... . .. . ............. 5-25
Interrupts. . ....... . ................. .. . ........ 5-25
Keyboard Controller. . ..... . ........ . .. ..... .. ..... 5-25
Keyboard Controller Microcomput er ........ . .. .. 5-25
Keycode Da ta .. ....... . ........................ 5-27
Thumbwheel Count Values ..... .. ... . ..... .. .... 5-27
Keyboard lndentif ic atlon ............. . ..... . .... 5-27
LED and Bell .. ............... .. ........ . ....... 5-27
Introduction to the Keyboard .. .... ........... ..... . 5-28
LEO and Be ll Log ic ........... .. ...... . .. . ...... ,..5-28
How a LED Changes State ...................... 5-28
Thumbwheel Interface
.. .. ........... ... ... . ....... 5-29
Thumbwheels and 2-Blt GreyCode ....... . ...... 5-29
Interfa cin g.of Thumbwheels
tothe
K04-K07 Lines .... . ... .. ... .. ...... ...... 5-29
Creating Key Change Data ... . ............... ... 5-29
Bell . .. ... ...................................... ..5- 29
How the Be ll Ri ngs ............ . ... .. ....... .... 5- 29
CharacterDecoder .. . ... . ... . ..................... 5-30
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Section 5 (cont)
RAM/ROM Board Theory ... . ..... ...... .... ........ . .... 5-30
General Description ........ ...... ... ............ ..... 5-30
General Operation .... ........... . .......... ..... .... 5- 30
RAM /ROM Board Circuit Bl ock Descri pt ions ......... 5-30
Bus Receivers ................ .................... 5- 30
RAM Control .. .. ... ........ ... .. . ... .... . .. ... . .. 5-30
Multiplexing ofRAM Addresses . .. ... ........... 5-32
Arbiter Circuitry ....... ............ . ..... . . ... .. 5-33
Timingand Control ..................... . ....... 5-33
Clock . ................... ......... ......... . ... 5-33
Dynamic RAM Controller Operations ........ ... ... . 5-33
Idling . .. . ........................... ... ........ 5-33
Write Cycle . ............ ... ...... .... . ......... 5-33
Read Cycle ............................. . ..... . 5-33
Refresh Cycle ....... .. ......................... 5-33
Data Input Buffers ................................. 5-34
RAM Array Board .......... . ........ . .... ............ 5-34
RAM Array Board Circuit Blocks ........ .. ......... 5-34
Data Output Latches ............................ 5-34
RAM Address Decode .. ........................ 5-34
Clock ..... ....... ....... ........... ....... ..... 5-34
ROM Address Decode . .. ....................... 5-34
ROM .................... .......... ..... ..... .. . 5-35
Data Output Drivers .... .......... .............. 5-35
RAM Controller Board Theory .............. .... .... . ... . 5-35
General Description .. .. . .......................... . .. 5-35
General Operation ......... ... ................ .... ... 5-35
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RAM Controller Board Circuit Block Descriptions .. .. .. 5-38
Bus Receivers ............................. .. ... .. 5-38
RAM Control .. .... .............. . ........... ... .. . 5-38
Multiplexing of RAM Addresses ............... .. 5-38
Arbiter Circuitry ................. . ......... . .. . . 5-38
Timing and Control .. . ........... . .......... .. .. 5-38
Dynamic RAM Controller Operation .... . .......... . 5-39
Idling .................. . .............. . ........ 5-39
Write Cycle ................................... . 5-39
Read Cycle ..... ... . .............. ........... .. 5-39
Refresh Cycle .................................. 5-39
Data InputBuffers .. .................... ........... 5-39
Data Output Latches .............................. 5-39
RAM BaseAddress Decode ......... • .............. 5-39
Clock ..................... .. ......... ............. 5-40
Bank Address Decode .... ........... .............. 5-40
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4112 SERVICE (VOLUME 1)

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Section 6 OISPLA V BUS THEORY
Introduction to Display Bus ................. ... ........ .6-1
Vi deo Contr oll er Board Th eory ........................ .. 6-1
General Description and Overview .................... 6-1
Video Controller Circuit Block Descriptions
...... .. .... 6-3
Master Clock .. . .... .... ........ ... ............... 6-3
VideoTiming Generator . ....... ...... ............. 6-4
P ix el Timing Control ............................... 6-5
RAM Timing Generator .......... .......... .. ...... 6-6
Memory Cycle Priority Control ............... . ..... 6-6
11 0 Address Decoder .. ............ .. ........... .. .6-1 O
1/0 Interrupts and Status ......................... .6-11
Power Supply Synchronizer
................ .. .. .... 6-12
X CursorCounter ..................... ........... . 6-12
Y Cursor Counter ........ ..................... .... 6-14
CursorVideo ............................ ... ..... .. 6-14
VideoDAC ................. . ....... ............... 6-1 6
50 HzOperation . . .... . ........................... 6-16
External Sync. ..... ... ..... .................... . .. 6-1 6
VectorGenerator Board Theory . ...................... .. 6- 18
General Description and Overview ............... ..... 6-18
VectorGenerator Circuit Block Descri pt ions ........... 6-21
Bus
Tr ansceiver ....... .... ....................... 6-21
110 Decode .......... ..... ........................ 6-21
Eight-Bit Counter
................................. 6-23
• Twelve-B
it Counter ................................ 6-24
Slope Generator .................................. 6-24
Y Axis Addressing Logic ...... ..................... 6-26
X Addressing Logic ............... ................ 6-27
Move and Wipe Log ic .. . ........................... 6-29
Pattern Shift Registers ............................ 6-30
Countar Control Logic ........................ ..... 6-31
Index File.
.... . ............ . ..................... . 6-32
Pixel Write Logic .. . ............................... 6-33
Memory Control logic .. ....................... .... 6-33
State Controller .. .................. . ...... .. .... .. 6- 34
Operating Modes .......................... . ...... . 6-37
Interpretingthe Flow Diagram ........................ 6-38
Mnemonics Used in Microcode FlowDiagram ....... 6-39
Memory Mode Control Field Mnemoni cs .... ...... .. 6-39
CounterControl Field Mnemon ics .................. 6-40
Memory Cycle Control Field Mnemoni cs ............ 6-40
Subroutine Names ................................ 6-40
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4112 SERVICE (VOLUME 1l vi

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Sec:· •• on 8 (cont)
Raster Memory Board Theory .......... ... . ... .. ... ..... 6-4 1
Introducti
on ..................... . ....... .. . .. ....... 6-41
Raster Memory Board Operating Modes
............... 6-42
Decodeand Startup Cycle ......................... 6- 42
Refresh Cycle ................... . ... ...... ........ 6-42
Vector Cycles .................................. . .. 6-44
Operate Cycle ...................... . ........... 6-44
Blockmove Source/Destination/Erase ..... . ... .. 6-44
Processor Read Cycle .... .................... .. 6-45
Circuit Block Descriptions ........ . ............. .. . .. . 6-46
Buffer ... ........................................ . 6-46
Addressable Latches .............................. 6-46
RAM Enable . .. .................................. . 6-46
RAM Control ..... . .............. . ........ . ........ 6-46
Vector Data Input ................. : ..... ... ....... 6-48
ALUsCircuit Block ....................... . .. .. .... 6-49
Blockmove Latch .............................. . ... 6-50
Memory Address Selectors ........................ 6-50
MemoryArray ................................. .... 6-51
ProcessorRead
latches ......................... .. 6-51
110 Decode ... . ................................... 6-52
VideoShiftRegister ............................... 6-52
VideoMap ....... . ............... .. .............. . 6-54
PowerComponents .. . ............................ 6-54
Dual Raster Memory Board .................... .. . .. ..... 6-54
Section 7 DISPLAYMODULETHEORY •
Introduction. .. .................................. ... . ... 7-1
Display Module Timing ........................ ...... . 7-2
Video Circuitry ......... . ................. . ........... 7-4
Multiplier Block ............ . .... .......... .. ...... 7-4
Level Shifter ............... . .............. .... . ... 7 -6
Video Amplifier .. ................... . ......... ..... 7-7
Horizontal Circuitry ....................... . ..... ..... 7-8
Horizontal Delay ...... .. ......................... . 7-8
Phase-Locked loop ............................ . .. 7-8
Horizontal Driver .................................. 7-9
Horizontal Output ................................. 7-10
Vertical Deflection Circuitry .. .... .................... 7-12
Synchronization Delay Circuit .... . ................. 7-12
Vertical Ramp Generator ......... . ................ 7- 12
Vertical Linearity ............................ . .. . .. 7 -13
Vertical Amplifier .................................. 7-13
High VoltageSupply ...... ... ... . ................. .. 7 -15
Error Amplifier ................................... .7 -15
TriggeredVariablePulseWidth Generator .......... 7-16
OutputCircuit. ....................... . ....... ..... 7-16
High Voltage Multiplierand Rectifier Circuit ........ 7-18
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411 2SERVICE (VO LUMf 1)

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Sec-tlon8
FUNCTIONAL CHECK
AND PERFORMANCE CHECKPROCEDURES
Introduc
ti on . ... . ...... ... .. .. .... . ... . ................. 8-1
Functional
Check Procedures. . .. .. ... ................. . 8-1
Power Up.
..... ....... . ................. ....... ...... 8-1
Adjustment
Self - Te st. .. . ............................. 8-2
The General Menu . .. .. .. ... . ........... ... .... . .. 8-2
41 12 Di splay Menu ...... . .............. . ......... 8-2
ProcessorBoard Menu ............................ 8-3
CMOS-Reset, Function Key Ft .. .. .............. 8-3
Keyboard,Function Key F2 ..... . .... .. ...... ... 8-3
HostPort Check,Function Key F3 ...... . ... . .... 8-3
Di sk Option Menu ............. . ................... 8-5
3PPI Adjustment Menu/Procedure .. . . .. .. ... .. ... . 8-6
TabletOption Menu .. . ..... .. ........ ... ... .. .. . .. 8-6
Tablet Timi ng Straps Verification ............... .... 8-7
Performance Check Procedures ..... ." .. ... .. .. . ..... . .. . 8-8
VIDEO Signal Level ........... .. ........ ... .. .. . ..... 8-8
HORIZ SYNCFrequency ........................... .. 8-8
VERTICAL SYNC Frequency .... .. ........ . ......... .. 8-8
Sectlon9
ADJUSTMENT PROCEDURES
RecommendedTest Equipment
........................ . 9-1
Di
sp l ay ModuleAdjustment Procedure ............. . ..... 9-2
Sho rt -Form Procedure ......... . ... .. ..... . ......... . 9-2
Long-Form Adjustment Procedure ........ . ......... .. 9-2
1. Initial Setup ...... .. ..... . ..... . ... . .. . ..... .. .. 9-2
2. Display Test Patterns ... ..... . .. ...... . .... .. ... 9-2
3. Check Horizontal Oscillator .. ... ..... . ....... . .. 9-4
4. Test Mode ........................... ... . .... ... 9-4
5.Null High Voltage Compensation. ... .. .. ......... 9-4
6. S9t D.C. Level. ...... . ... . .... . .. . .. .. .. .... . .. .. 9-4
7. G1 (Grid 1) Level Chee ls ..... . .... . ..... . ... .. . .. 9-4
8.Focus Adjustment. .... . ..... .. ............. . .... 9-4
9. Picture Centering Procedure . .. .... ....... .... .. 9-5
10 .Final Linearityand Size Adjustments .. ... .. .... 9-6
11 .Gray ScaleTracking and
Maximum Luminance Adjustment. ... . .......... 9-6
12 .Resolution Test. ....... . .. . .............. . ..... 9-6
13 .Horizontal OscillatorAdjustment ............... 9-7
14 .Hi gh Voltage AC Ripple Test . . .. ............... 9-7
15 .Measure High Voltage .. ..... . .. .. .... .... . . .. . 9-7
Power Supply Adjustments ... ..... . .. ... .. .......... .. .. 9-8
1. DC Voltages ................. ... . .. . .. .. . ....... 9-8
2. CHECK -Control Voltages .......... . .. .. .. ... . .. 9·8
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4112 SERVICE (V OL UME l)
viii

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Section 10 TROUBLESHOOTING AND SELF-TESTDIAGNOSTIC
Troubleshooting,
lnitialNisual Checks ............ . ..... . 10- 1
Display ModuleProblems
.... ..... .. ..... . ........... 10-1
Low Voltage Power Supply Problems
................ .. 10-2
Disk Option Tr oubleshooting .. ..................... .. 10-2
lnitialNisual Checks .............. ..... . .......... 10-2
Disk Media Problems .... ........... .. . ....... ..... 1 0-2
Hard and Soft Errors ... . ....... . ...... ......... . .. 10-2
Disk Drive UnitFaults . .. .. . .. .. .................. . 10-2
Self-Test Diagnostic Program .............. ... ... .. .. . .. 10-3
Parts of Self-Test ........... .............. . .. .... ... . 10-3
Power-Up. .............. .............. ..... ... .... 10 -3
Main Self-Test .
........ .... ..... . ...... . .......... 10-4
Adjustment Routine .. . .. .. . ................ ... .... 10-4
7x System Errors Detector .......... .. . ...... ...... 1 0-4
Control Flowof Self-Test ............... . .. .. ......... t 0-4
Self-TestFirmware Jump Tables ...... . ....... . ....... 10-7
How to Run Self-Test ..... ......................... .. 10-7
Self-Test ErrorMessages ......... ... .............. .. . .. 10-9
Errors Directory .......... .. .............. ... ......... 10-9
Non-Option Error Messages ................. ..... .... 1 0-9
Keyboard Check and Lights .................... ... 10-1O
ProcessorCheck. ............................ .. ... 10-12
Communications and Bus Checks ................ .. 1 0-16
MemoryTests ............................ .. ....... 10-19
ROM Check
(C) ............................... . 1 0-19
RAM Check (B). ............ . .... .. ... .. ... ... .. 1 0-22
CMOS Check (AF) .. .......................... . .1 0-24
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Display Bus Checks (8) .. ......................... .1 0-25
System Level Errors (7x) ........... .... .............. 10-27
4112 Option Tests and Error Messages ... .. ...... .... 10-29
3PPI Board Tests ..................... . ........... 10-29
Option 42 Self-Test Error Messages .... .. ... .... ... 10-31
TZ!blet Self-Test ErrorCodes
...... ... .............. 1 0-39
Adjustment Self-Test ................... . .. . .. .......... 10-42
The General Menu ................................. .. 1'0-42
4112 DisplayAdjustment Menu.. .. .. .... ............ . 1 0-43
Processor Board Adjustment Menu/Procedure ........ 1 0-43
CMOS-Reset, Function Key F1 ..................... 1 0-43
Keyboard,Function Key F2 . .. .. ... ............... . 1 0-44
HostPort Check,Function Key F3 ........... . .... . . 10-44
D isk Option Adjustment Menu/Procedure ...... .. .. .. . 1 0-45
3PPI Adjustment Menu/Procedure ............... .... .1 0-45
Tablet Adjustment Menu/Procedure ................. .. 1 0-46
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4112 SERVICE (VOLUME 1)

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Section 11 MAINTENANCE
Safety Conslderations
.... ... . ...... .. .... .... . ... .... 11 -1
Preventive Maintenance Schedules .. .. ......... .. . . ..... 11-1
Cleaning and Preventive Maintenance
of Disola/
Module, Keyboard, and Internal Parts . .... .. .. ....... . 11 -1
Cleaning
the Keyboard . .... . .... .. .. .. .... .. ...... 11-1
Rout
ine Visual Inspection ... .. .... ... .. . . . .... . .... . 11-2
Low-Voltage Power Supply Maintenance ....... . ...... 11-2
Fu seReplacement . ......... .... . ........ .. ...... .11-3
Disk Drive Options (42 143) ......... . ........ . .. ...... 11-3
Disassembly/Reassembly Procedures . .. . .... .. .... . ... . 11-4
Removing Main Cover Panel ...... . ...... ... ...... . ... 11-4
Accessing Card-Cage. ... . .. ... . ... .. ... .. ... ..•. . .. 11-4
Remov ing Circuit Boa rds ............... . ......... .... 11-4
Removing Drive Unit ..... . ............. .. .. .. . ....... 11-6
Re installingDrive Unit .. . ... ... ........ ... ..... . .. . . 11-7
Dr ive UnitDisassembly/ReassemblyProcedures ...... 11- 7
Removing and
Re installing
the Low-Voltage Power Supply .... .. ................. 11 -7
Removing andReinstalling the Display Module . .. . .... 11-7
Removing andReinstalling
Display Module
Circuit Boards .. . ........ ....... . ..... 11-9
Removingand Reinstalling the Display CRT .... ..... .. 11-9
UpperFan Replacement. .................. .... . ...... 11-1O
Lower (Squirrel-Cage) Fan Replacement .. . .. ......... 11 -1 O
• Write-Protect and Contrast Controls Replacement
..... 11 - 11
RemovingRearCoverPanel .. . ... ......... ........... 11 -11
Removing/Replacing
the Keyboard Assembly ......... 11-12
Replacing Keyboard
Key Caps ..... ..... .. . .. . ........ 11 -1 3
Appendix A SIGNALS LIST
Appendix B STRAPINFORMATION SUMMARY
Processor Board Straps
....................... .......... B-1
Keyboard Straps . .................................. . .. .B-2
RAM/ROM and RAM BoardController Straps
..... ........ B-2
Video Controller Board Straps .. .. ..... ...... . ........... B-2
Vector Generator Board Straps .......................... B-4
Raster Memory Board Straps ................. . ...... ... .B-4
Dual Plane Raster Memory Board Straps
................. B-4
Ex te rnal Video Board Straps .. ......... .. ...... ... ...... 8-4
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4112 SERVI Cf <VOLU ME 1) x

•
Appendix C EXTERNAL VIDEO OPTION
Introduction ...... .. ... ....... . .. .. .. .. ..... .. ........ ..C-1
Related Documenation
... . ... .... . .. . ................ C-1
Product Description. . ... ... .. .. ... ... ... ... .. .
... .. .C -1
Specifications. .. ..... .................... . .. .. .... ... . C-2
Electrical
.. . .......... . ... ..... .. .... ....... . .. . .... .C -?
Environmental ...... . .......... .. .... . ...... ......... C -2
Theory of Operation ................ ... .. ....... .. .... .. C-2
Introduction .
..... .. .. . .... .... . .. ............. . ..... C-2
ScanConversion Buffer
.......... . ..... . ... . .. . ... C-2
Line Control .
... .......... . ........ .. ........ . .. .. C-3
DAC (Digital-to-AnalogConverter)... ............... C-3
External Synchronization ..... .. ...... . ... ..... . ... C-5
Scan Conversion Buffer Operation.
...... ... ... . ...... C-5
Input Latch
..... . .................... . .... . ....... C-5
Input ShiftRegi
ster .................... ... ......... C-5
Input Buffer
.. .. ... .... ...... . .... .. . .............. C-5
Memory
............... . ..... . ....... .. .. . ...... ..C-5
Output Buffer
..................... . ..... . ....... .. C-5
Output Shift Register
..... .. .......... .. ... .. ..... .C-5
Output Latch
.. .. .. .. ................ . ..... ... .. . .. C-6
Write Control
... ... .......... . ............ ..... .. . C-6
Write Counter......... .... . .......... . ............ C-6
Read Contro
l. ............. . .. .... . .... ... .... .. . .. C-6
Read Counters .... ... ......... . ........ . ... .. ... .. C-6
Address Multiplexer .. ... .. . .... .... .. ..... . .. ... .. C-6
External Dot Clock .. ..... ... .. . ..... . ............ . C-6
Line Control Circuitry ..... . ...... . .... . .. .. ...... ... . C-7 •
LineControl . ... ... ........... .. ... . ..... ... .. .... C-7
Line Counter
.. . .... . .......... . .......... .. ..... . .C-7
Horizontal Synchronization ..
.. . ........ .. ....... . .C-7
Vertical Synchronization.
.... . .... . ........ . ....... C- 7
Horizontal and Vertical Blanking
.. . .. . .. .. .... . .... C-8
DAC and AmplifierOperation .... . .. ...... ... . .. .... .. C-8
External Synchronization ... ... .. ... .. . ..... . .. . ...... C-8
External SyncDeteclor .. . .. ... . ... .. .... . .. . .. ... . C-8
External Synchronization Control .. . ......... .. .... C-8
TimingSection .. ........ ..... . .. . ... . . .. ... . ....... . C-9
Field Installation .. ... ... ...... ... .. ... .. . . .... . .. ... . . .. C-9
Equipment Required
........... .. .. . ... .. ........ . ... C-9
Installation Procedure.. .. ... . .. . . ... .. .. .. . ........ . .C-1O
Strap Settings
... ....... . .... ......... ...... .. .. ... . .... C-13
••
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4112 SERVICE (VOLUME 1)

• Appendix D
OPTIONS INSTALLATION
Option 1 (Extended Communications) ................... 0-1
Introduction
.... ..... ...... ... .. ..... ............. . .. 0-1
Tools Required
... . .. ...... . ... . ............... . ..... D-1
Installation ...................... . .......... . ....... .0-1
Options 4A -4F (Keyboards)
..... . ............... ... ... D-2
Introduction
.. .. . .. ......... ... ........... .. ....... ..D-2
Tools Required ..... .. .. .. ...... .. ... . .. .... ..... .
.. D-2
Keyboard ROM Installation Procedure .
............ .. .D-2
Cutting the Keyboard Straps
.. ... ............ . .. ..... .D-4
Replacing the Keyboard Key Caps
...... ... ........... D-6
Options 24 -29
....................................... D-13
In
tr oduction ............ .. . .... ....... .. ...... . .... .. D- 13
Tools Required ...... .... .. . ...... . .. . ......... ... ... D- 13
Installation ..... ... .......... . ....................... 0- 13
Memory_Quantity Verification Check .. .. ...... ........ D-14
Changing the Line Voltage (110V -220V).
... .. ... . ..... D-15
Changing the
Li ne Frequency (60Hz -59Hzl ..... . ....... 0-16
Appendix E RESTORING FACTOf!N DEFAULTS
Appendix F MEMORY USAGE
The '' STATUS MEMORY" Command ...... ...... .. .. .. . .. F-1
Calculating User-Available Memory ........ .. .. . ....... .. F-1
•
AppendlxG MEMORY MAP
•
4112 SERVICE (VOLUME 1) x
ii

xiii
ILLUSTRATIONS
Agure Desc ri p tion Page
1-1 The 4112 Computer Display Terminal. ........................ xxii
1-2 4112 Functional Modules ......................... ..... ...... 1-2
1-3 Front-Panel Features .. .. ... .. .... . ... ........... ........... 1-3
1-4 Rear-Panel Features .................. . ............. . ....... . 1 -5
2-1 Controls, Indicators.and Keys .................. .............. 2-2
2-2 Keyboard Layout ................... ..... .................... 2-3
2-3 Sam pl es of Hard Copy ............................. . ....... . . 2-4
2- 4 Display Control Keys and Thumbwheels ....................... 2-5
2-5 Rear View Showing the Fuse, Controls,and Connectors . .... ... 2-7
3-1 4
112 Physical Dimensions ................................... 3-2
4-1 Window-Viewport Transform .......... .. ......... . .... ..... ..4-2
4-2 ScreenTwo Viewports ..... .. . .. ..................... . ..... .. 4-3
4-3 Constructing a Display Pattern from Pixels ........... .. ...... . 4-4
4-4
4112 Alphatext CharacterArray ....... . .......... .. .......... 4-5
4-5
411 2 Overall Bl o ck Diagram. . . .. .. . ... .. .... . . .............. 4- 7
4
-6 Physical Layout of Processor/Display Susses ................. 4-8
5-1
5-2
5-3
5-4
5- 5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5- 13
5-14
5-15
5 -16
Simp li fied Block Diagram of Processor Board ..... ... . ......... 5-2
Processor Board Block Diagram ................. ..... .... . ... 5-5
MPU Functional Block Diagram ..... ............... ..... ...... 5- 7
Programmable InterruptController
Block Diagram ... ... . ..... 5-9
Bus Controller Block Diagram ... ................ . ............ 5-11
Bus Contro
ll er Timing. ... .... ... ..... ... .. . ..... . .. ... . ... .. 5-13
ROMs Bank Decoder Logic ....................... .. .......... 5-1 5
Bus Clock Genera
tor Timing ................... . ............. . 5-20
MPU Timing Generator Circuit ................... .... ......... 5-21
Programmable Communications Interlace
Block Diagram ...... 5-24
Keyboard Controller Microprocessor Block Diagram . ..... ..... 5-26
Keyboard Block Diagram ..... ...... ................. ....... .. 5-28
RAM/ROM Block Diagram ...................... ... ........... 5-3 1
Dynamic RAM Controller
Block Diagram .. ........... . ......... 5-32
RAM Controller Board B lock Diagram ..... .. .................. 5-36
RAM Controller Boards and Memory Address Space ........... 5-37
6 -1 Video Controller Board Bloc k Diagram ........................ 6-2
6-2 MasterClock Timing Diagram ....... ........................ . 6-3
6 -3 Pixel Timing Diagram ..................... .. .. ............... . 6-5
6-4
RAM Timing GeneratorCircuitry .............................. 6-7
6-5 RAM Timing for Raster Memory System ....... .... ............ 6-8
6-6 MemoryCycle Priority Control Gates. .......... .. ............. 6-9
4112 SERVICE (VOLUME 1)
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• Figure Description Page
6-7
Inte rrupts and StatusReg is ters ........................... .... 6-11
6-8 X Cursor Operation ........................... ..... . .... ..... 6 -1 3
6-9 Y Cursor Operation ........... .... ........... . ....... ..... . .. 6-15
6-10
Analog Output of the DAC .............................. ..... .6-17
6-11 Vector Generator Board Simplified
Block Diagram ............. 6-1 9
6-12 Vector Generator Board Block Diagram ... ......... ........... 6-20
6-13 Data Bus Transceiver, 1/0 Decode.
Write Sync, and SACK Logic.
...... . ... .. . .. ... ........ .. .... 6-22
6-14
Write Synchronization Timing Diagram . .... .. . .... ... ... ...... 6-23
6-15 Slope Gen&rator Block Diagram .. ... ...... .. ... . ......... . .. . 6-25
6-16
l::. Y and Y Counters (Y AddressingLogic) .. . ....... .... .... . .. 6-26
6-17
XAxis Addressing Logic ............. ...... .... ... .. .... ... .. 6-27
6-18 Pattern Shift Register .. .. ... ......................... .. ...... 6-30
6-19 State Controller
Block Diagram ....... ..... ...... ....... . ..... 6-35
6-20
Address Sequencer. .......... ......... .. .................... 6-36
6-21 Power-Up Routine
..... ...................................... 6-57 ·
6-22 DRAWO and DRAW1 Routines ................................ 6- 57
6-23 Block Move Routine ......................................... 6-58
6-24
Wipe (Erase) Routine ................ . ........ . ... . .......... 6-58
6-25
ASCII Dot Matrix Routine ............................... . ..... 6-59
6-26
Raster Memory Si mp lified Block Diagram ..................... 6-43
6-27
A 20-Pixel Wide Str ip Compared to a 20-Bit Word . ....... ... .. 6-45
6-28
Single Plane Raster Memory Board Block Diagram. ... ........ . 6-47
•
6-29
6-30
6-31
Vector Data Input B
lock . ... ......... .............. . ... ..... .. 6-48
ALUs Circuit Block Diagram .... . ........ .... ... .... .. ...... .. 6- 49
Memory Array Diagram ........ ...... ... ...... .... ....... ..... 6-51
6-32 Video Shift Reg ister .......................................... 6-53
6- 33 One Scan Line Showing Border Video ................... ...... 6-53
6-34
Video Map (Single Plane and Cursor) ...... . .......... .. ...... 6-60
6-35
Video Map(Three Plane Interpreter) ................... ....... 6-61
6:-36 Video MapReprogrammed
by Processor . ............. . ....... 6-62
6-37
Video Map(One Plane and Cursor) andDisplay .... ......... . .. 6-55
6-38 Video Map (3 Planes -Shading) and Displ ay ........ . ..... ... 6-56
7-1 Disp lay ModuleSimplified Block Diagram ........... .... .... . . 7-1
7-2 Di splay Image Composition ....... ........ ..... .... ... . ....... 7 -2
7-3 Sync and BlankingTiming D ia gram ........................... 7-3
7-4
Video Circuit Bl ock Diagram. ......................... ....... . 7-4
7-5
Multiplier Circu it Block Diagram ........................... ... 7-5
7-6 Level Shifter andVideoAmplifier ......... ........ ........ . . .. 7-6
7-7 Wave Shaping by In du ctor Co il ....... . ................ . ...... 7-7
7-8 Horizontal Circuitry Block Diagram .... . .... .. .... .. ........... 7-8
7-9
Phase-Locked Lo op Circuit Diagram ............... ... ..... ... 7-9
7-10 Horizontal Driver and Output Circuit .... . ....... . ............. 7-1 o
7-1 1 CRTSweep Wavefor ms . ...... .... . ...... . ..... .......... .... 7-11
7-12 Vertical Circuitry Blocks ........ .... .......... . ... .. ......... 7-12
7-13 Deflection Waveforms .......................... . ... .. ... . .... 7-13
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Figure
Description
Page
7 -1 4 Vert ic al Output Circu it .................. . ......... . .... ...... 7-14
7- 15 High Voltage Supply .. .. ..... . .. .......... ... . ... . .... .. . .... 7 -1 5
7-16 Error Amplifier
and
Pulse Width Circuits Functional Diagram .... ... ....... ..... .. . 7-16
7-17 Output Ci rcuit Functional Diagram ... .. .............. ........ . 7- 17
7-18 Multi plier and Rect ifier Functional D ta yram... .. ... ........ ... . 7-18
7- 19 lntenial Operation of CRT ...... . .................... . . ....... 7 -19
8-1 Keyboard Key Codes .... . .. . ......... . ...... . .. . .. .. . ........ 8-4
8-2 Tablet Controller B bard Timing Strap Locations ..... ... ....... . 8-7
9- 1 Display Module Adjustment Locatio ns .. ... .. . . . ........ .... .. . 9-9
9-2 CRT Ca t hode Signal .. ..... ........... .. ... .. ....... ... . .. . . . 9- 4
9-3 Picture Adjustment Pattern ... . .............. . ............ .... 9 -5
9-4 Power Supply Test Poi nts ... .. . . .. .... ... ... . . . ... ... ........ 9-8
10 -1
1
0- 2
10- 3
10-4
10 ·5
10·6
10 -7 A
10 -7 B
10-7C
10-7D
10-7E
10·7F
10·7G
10·7H
10-71
10-7J
10-7K
11-1
11 ·2
11 -3
11 -4
11·5
1H3
11-7
11-8
11 -9
11·10
11 - 11
11 · 12
11-13
Self-TestFunctional Diagram .............. .. ..... . ...... .. .. . 10-3
Self-Test Program Block Diagram. . . .. ............ . ..... ...... 10-5
The ROM Header-Pointer Diagram ... .. . .... ....... ... ...... .. 10-7
RAM/ROM Board ROM Locati ons .. ........ . . ... . . ............ 10 -10
Processor Board ROM Locations ............ ..... .. . ... ...... 10-12
Status Byte .. .. . . ............. .. .. . ....... .......... ......... 10 -19
Self-Test Flow Chart .. .. ........ ... ... .. ... .. ..... .. . . .. ..... 10-47
Self-Test Flow Chart ... . .................. ..... .... .. . ....... 10-49
Self-TestFlow Chart . ........ ... .. . ...... . ..... ..... .... ..... 10-51
Self-TestFlow Chart .
..... .. ......................... ..... . .. 10-53
Self-TestFlow Chart ........... .. ... .. . .. ... . .. . ..... . ....... 10-55
Self-Test Flow Chart .... .. . ... . ...... . ... . . ................ .. 10-57
Self-Test Flow Chart ................. . . .. ......... . . ......... 10-59
3PPI Self-Test F low Chart ............... ......... .. . .. . ...... 10-61
Disk Self·Test FlowChart .. ... ............ .............. ... .. 10-63
Di sk Self-Test Flow Cha rt ........ . .. ... ..... .... . . ..... . ..... 10-65
Tablet Self-TN;t Flow Chart .. ....... . .. . ....... .. .... .. ...... 1Q.67
Power
Supply Switches and Fuse Holder ..... . .. . ........ .... . 11-2
Location of Cover Panel Mounting Screws .................... . 11 -4
locat ion of Card-Cage Mounting Screws: .... .. . .... .... . : .... 11-4
411 2 Motherboard .......... ............... .. . . .. . . ........ .. 11 -5
lifting Tabs and Pulli ng Circuit Board .... ........ ...... . ...... 11-4
Removing Wrap-Around Cover ......... ........ ... .. .......... 11-6
Left-Rear View of Drive Unit .. . . . . . . . . . . .... ....... . . .... .... 11-6
D is mounting the Dr iv e Unit . .. .... . ... .. . .. . . .. . ..... .. ....... 11 -6
D ri ve Un it Enclosure Mounting Screws ........ . . .... .. . .... . . . 11- 7
Bezel Upper Mounting Screws
and
Refresh IntensityControl .... . ........ ..... . .. . .. .......... . .. 11 -7
Bezel Left
and Ri ght Mounti ng Screws . . . . . .. .. . . .. ... ....... 11-8
Display M odu le Base Mounting Screws ...... . ......... . ...... 11-8
D is play Module Upper Mou nting Screws .... . . .. . ... . ........ . 11-8
411 2 SERVICE (VOLUME 1)
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..
•
Figure
Description Page
11-14 Removing H.V.Anode Cable from CRT ......................... 11-9
11-15 Removing Upper Cooli ng Fan ................................. 11-1O
11-16 Removing LowerCooling Fan ................ . ..... .. . .. . ..... 11-1O
11-17 Removing RearCover Panel ........................ ....... ... 11-11
11-18 Removing the Keyboard As sembly ................... . ........ 11 -1 2'
11-19 Installing Replacement Key Cap .............. .. .. . .. ......... 11 -13
B-1 Strapping RAM Controller Board Base Address ................ B-3
C-1 External Video Option BasicFunction ... . ...... ........ .. .. . .. C-1
C-2 Simplified BlockDiagram ........................... . .... . ... C-3
C-3
External Video Board BlockDiagram .......................... C-4
C-4 Aspect RatioCorrection ........... . .......... .. . ....... . .... .C-7
C-5 Top-Cover Mounting Screws ...................... ... .. ... .. . C-1 O
C-6 Rear-Panel Mounting Screws ................................. C-10
C-7 MountingRear-Panel Connectors ............................. C-10
C-8
Cable Route. via Card-Cage to Rear Panel. .................. ..C-11
C-9 Card-Cage Mounting Screws ................................ . C-1 2
C-10 External Video Board in Slot Nine of Card-Cage ............... C-12
D-1 Top-Cover Mounting Screws ............................ . .... D-1
D-2 Card-Cage Mounting Screws ............................. . ...D-2
D-3 RAM /ROM Board (Option 4X ROM Location) .................. D-3
•
D-4
D-5
D-6
Removing and Disassembling the Keyboard Assembly ......... D-5
Keyboard Circuit Board Strap Locations
.......... . ... ... .. . .. D-4
United Kingdom Keyboard
......... . .............. . .. . .... . ... D-6
D-7 Swedish Keyboard
............................... . .... . ... . .. D-7
D-8 Danish/Norwegian Keyboard ...... . ....... . .... .. .. .......... D-7
D-9 APL Keyboard ... .. ... .. .. .......... . ........................ D-8
D-10 InstallingReplacement Key Cap ...... . .. . ...... .. . .... . ... ... D-8
D-11 Changing Line Voltage
..... . ....................... . ......... D-15
D-12 DiskDrive Unit Belt and Pulleys
.............................. D-17
E-1
Self-Test Menu ....... . ...... . .. ... .......................... E-1
E-2 Processor Board Menu .................... .... ............... E-1
E-3 CMOS Reset Message .......................... .. ........... E-1
..
G-1 4112 Memory Map
........................................... G-1
•4112 SERVICE (V
OLUME 1)
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TABLES
Table Descrip ti on Page
1-1
41120pt ions ......... ..................................... .. 1-7
2-1 Getting Ready and Turning
On the 4112 ......... . ... ..... .. .. 2-11
2-2 Creating a Segment ..... .. .......... . .. .......... . ........... 2- 13
2-3 Manipulating a Graphics Segment ............................ 2-14
2-4 Using GIN (Graphics Input) Mode .... .. . . ........... .. ....... . 2 -1 6
3-1 Phys
ic al Characteristics .............................. . ...... 3- 1
3-2 Environmental Characteristics .......................... ...... 3-3
3-3 Electrical Characteristics .... ............... ... .............. 3 -3
3-4 Display Module Characteristics .. . ............................ 3-4
3-5 Installation Requirements ... ....... ... ..... . ............... .. 3-4
3-6 Graphi cs Characteristics. ....................... ...... . ...... 3-5
3-7 Alphanumeric Character Sets ..... . ... . .......... .. .......... 3-5
4 -1
4-2
4 -3
4-4
4-5
80-Pin ConnectorSignals (Processor Bus Only) ........... . ... 4-9
80-Pin Connector Signals (Video Controller On ly) ...... ....... 4-11
80 -Pin Connector Signals
(DisplayBus,except Video Controller)
........................ 4-12
44-P ln Connector Signa ls (D ispl ay Bus) ....................... 4-15
50-Pin Front-Edge ConnectorSignals .............. .. ......... 4-16
5-1 Manufacturers' Nomenclature for L SI Circuits . ... .. .... . .. .. .. 5-6
5-2
Status Word and Bus Controller Commands ................... 5-12
5-3 Selection Bits f or ROM Banks .................. ... .......... . 5- 15
5-4 Proce ssor Bo ard Address Enabling Signals . . ... .... ......... . 5-18
5-5 MPU State and MPU Timing Generator Signals .... ... ........ . 5-2 1
6-1 1/0 Address Signals
........... . ............... , .............. 6-10
6-2 Mask Register Address Selectlon .... ... ...................... 6-29
6-3 Counter Control ROM Modes ........ ....... . .... .. . .. .... . ... 6-31
6-4 Memory Control ROM Modes ................................. 6-33
6-5 MODE0-0 and MODE1-0 Decoder ....... . ... .. ..... . ......... 6-44
6-6 ALU Function Selection ............... .. ................... .. 6-50
8-1 Adjustment Control Keys ........... ... ... ...... .. .. ......... . 8-2
9-1 Recommended T est Equipment... ............................ 9-1
9-2 D is play Module Adjustments .......... .................. ... .. 9-3
9-3 411 2 Displ ay Menu ............... .. .......... ............... 9-2
9-4 Power Sup ply Voltage Limits ................ . .... .... ....... . 9-8
4112 SERVICE (VOLUME 1)
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Table
Description
Page
10-1 Power-Up/Self-Test Sequence
......................... ... ... 10-6
10-2
Self-Test ErrorsDirectory ..... .. ...... . ...... . .... . ... .. ..... 10-9
10-3
Keyboard/Processor Board Errors .. . .. . .. ....... .. .. ..... .. .. 10 -11
10 -4 Processor Board Errors
.................... ... .. ...... . .. .... 10-1 3
10-5 RAM/Bus and Host Port Errors
........ . ...................... 1 0-16
10-6
Hex-to-Decimal Equivalents .......... ... . .......... .. ... ..... 10-19
10-7
System/Option ROMs Errors . ...... ... . .. ............ ..... . .. 10 -20
10-8 RAM Test Errors .................... .. . .. .... ........ .... .... 10-22
10-9
CMOS Memory Errors .. .... ... . .. . .. ....... . .... ............. 10-24
10-10
Display Bus/Board and System Errors ... ......... . . .......... 1 0-25
10 - 11 System Level Errors (7x Codes) . ... . . .... .. ..... .... ... .. ... . 10 - 27
10-12
3PPI Errors. . .. .... . ... . ........... ...... ..... .... . .. ...... .. 10-29
10-13
Disk Option Errors ... ...... .. .... ... . .... .. .......... .. .... .. 10-31
10-14
Tablet Error Messages .. ... . ... .... ..... . .. . ... ........... .. . 10-39
10-15
Adjustment Control Keys ... .. .. .... .. ... . ....... . .. . ....... .. 1 0-42
11-1 Fuse Replacement Values
....... .................. ... .... .. .. 11 -3
11-2
Disk Drive UnitMaintenance Schedule ... .. .. ..... . ... .. ... ... 11-3
A-1
Signals List. .......... ....... .... ... .. . ... ........... ........ A-1
B-1 Processor Board Strap Settings
......... .... ........ .. . .... . . 8-1
B-2
Keyboard Language Option Straps ....... ... ...... .... ........ B-2
•
B-3
8-4
Video Controller Board Straps .... . ... .. . ....... . ...... . .... .. B-2
External VideoStraps ..... ... ....... .... . .. . ......... . .. ..... 8-4
C-1 Strap Settings
...... .. ............. ............. . .... .. .. .... C-13
C-2
·v'ideo Levels. ........ .. ........ . .. ....... .... ....... ......... C-1 3
D-1
Keyboard Language Option Straps ........ ... ........ . ........ D-4
D-2 United Kingdom Character Set.
................ ......... . ..... D-9
D-3 Swedish Character
Set.. ..... . .............. . . ....... ....... . D-1 O
D-4 Danish/Norwegian CharacterSet
.. ... ..... . .. ............. . .. D-11
D-5 APL Character Set
................... .. ...... ................ D-1 2
F-1
Use ofRAM at Power-Up . .. . .. ............... . .. ..... .... .. .. F-2
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4112 SERVICE (VOLUME 1) xviii