NCR PC4I User manual

PC4i
Service Manual

C op yright c 1986 by NC R Corporatio n
Dayton, Ohio
All R ig hts Reserved
Printed in the Federal Republic of Germany
March 1986
It is the policy of NCR Corporation to improve products as new
technology, components, software, and firmware become available.
NCR Corporation, therefore, reserves the right to change specifica
tions without prior notice.
All features, functions, and operations described herein may not be
marketed by NCR in all parts of the world. In some instances, photo
graphs are of equipment prototypes. Therefore, before using this docu
ment, consult your NCR representative or NCR office for information
that is applicable and current.

NCR PERSONAL COMPUTER PC i»i
SERVICE MANUAL
CONTENTS
Chapter 1 System Overview
NCR Personal Computer Hardware ................. 1-1
Display Unit .................................... 1-1
Models .......................................... 1-3
Model Numbers ................................... 1-5
Tools .......................................... 1-6
Alternate Main Processor Board ................. 1-8
Chapter 2 Basic Troubleshooting
Level 0 (Pov/er-On) Diagnostics ................ 2-1
Power On ...................................... 2-2
Power Cords and Switches ....................... 2-2
Memory Test Messages .......................... 2-3
After First Attempt ........................... 2-6
After Second Attempt .......................... 2-7
Power Supply ................................... 2-9
Peripherals
................................... 2-17
Check Keyboard ................................ 2-17
Check for Diagnostic Errors .................... 2-17
Restore Full Configuration .................... 2-19
Test Total Memory ............................. 2-19
Test CRT and Disk Drives ..................... 2-20
Re-Installation ............................... 2-22
Chapter 3 Level 0 Diagnostics
Memory Test ..................................... 3-1
Other MPB Tests ......... 3-5
Keyboard Test .................................. 3-5
Initialization and Loading .................. 3-5
Error Returns .................................. 3-6
Parallel Port Error Codes
...................... 3-7
Level 0 Loop Tests on Generic Processor Board .. 3-7
Error Messages of the Early-Type M P B .......... 3-11*
Suggested Action ............................... 3-15

Chapter 4 Level 1 Diagnostics
How to Begin Testing .......................... 4-1
Load the Diskette ........................... 4-1
Main Menu ..................................... 4-2
Main Menu Help Screens
........................ 4-5
Test Completion Displays ...................... 4-6
Diagnostic Selections ......................... 4-8
Run all Tests Once ........................... 4-9
Automatic Completion ......................... 4-9
Memory (Main Menu Selection 1) ............... 4-11
Memory Test Help Screens ...................... 4-12
RAM Pattern Test ............................. 4-12
RAM Address Test .............................. 4-13
RAM Parity Test ............................. 4-14
RAM Walking Ones Test ........................ 4-15
Firmware Checksum Test ........................ 4-16
Controllers (Main Menu Selection 2) ........... 4-17
Controllers Test Help Screens ................. 4-18
CPU Test ..................................... 4-18
DMA Test ...................................... 4-19
Flexible Disk Controller Test ................. 4-20
Interval Timer Test ........................... 4-21
Interrupt Controller Test ..................... 4-22
CPU Controller Test ........................... 4-23
Monochrome Display Controller Test ............ 4-24
Color Graphics Display Controller Test ....... 4-23
Serial Synchronous Controller Test ............ 4-26
Keyboard (Main Menu Selection 3) .............. 4-26
Flexible Disk Drive (Main Menu Selection 4) .... 4-28
Flexible Disk Drives HELP Screens ............. 4-28
Read Only Drive A Test ........................ 4-29
Read/Write Drive A Test ....................... 4-30
Fixed Disk Drive (Main Menu Selection 5) ..... 4-31
Fixed Disk Drive Test HELP S c r e e n ............ 4-32
Read/Write Maintenance Track ................. 4-32
Read Only Sector 0 ........................... 4-33
Read Only Entire Disk ......................... 4-34
Read/Write Entire Disk ........................ 4-35
Fixed Disk Controller ......................... 4-38
Monochrome Display (Main Menu Selection 6) ..... 4-39
Color/Graphics Display (Main Menu Selection 7).. 4-41
Peripherals (Main Menu Selection 8) .......... 4-47
Serial Port Loopback Test ..................... 4-48
Parallel Port Loopback Test ................... 4-49

Printer Tests ................................ 4-50
Generic Printer Test
.......................... 4-51
PC Compatible Printer Test ........... 4-52
Utilities ..................................... 4-53
Videotex Adapter Tests (Main Menu Selection).... 4-54
Local Test
................................... 4-55
Remote Test ................................. 4-55
Picture Test ................................. 4-57
Chapter 5 Level 1 Diagnostic Error Returns
Repair Guidelines ............................. 5-1
Basic System Configuration ..................... 5-1
Preliminary Checks ............................. 5-2
Main Processor Board Components ................ 5-3
Memory Addressing .............................. 5-5
Error Codes .................................... 5-8
Relationship between Detail Codes and
Repair Procedures ............................. 5-8
Format of Displayed Error Codes .............. 5-10
List of Major Error Codes
.................... 5-10
Memory Error Codes ........................... 5-12
Repair Procedure 01 ......................... 5-13
Repair Procedure 02 ......................... 5-18
Repair Procedure 03 5-20
Repair Procedure 04 5-21
Repair Procedure 05 5-21
Flexible Disk Drive Error Codes .............. 5-23
Repair Procedure 06 ......................... 5-25
Keyboard Error Codes ......................... 5-32
Repair Procedure 07 ......................... 5-32
Video Display Error Codes .................... 5-34
Repair Procedure 08 ......................... 5-35
Repair Procedure 09 ......................... 5-37
Peripheral Error Codes ....................... 5-38
Repair Procedure 10 5-40
Repair Procedure 11 5-43
Repair Procedure 12 5-46
Major System Controller Error Codes
.......... 5-39
Repair Procedure 13
......................... 5-47
Repair Procedure 14 ......................... 5-48
Repair Procedure 15 ......................... 5-48
Repair Procedure 16 ......................... 5-49
Repair Procedure 17 5-50

Repair Procedure 18 ......................... 5-51
Repair Procedure 19 ......................... 5-52
Repair Procedure 20 ......................... 5-52
Fixed Disk Controller Error Codes .............. 5-53
Repair Procedure 21 ......................... 5-53
Repair Procedure 22 ......................... 5-54
Videotex Error Codes ......................... 5-56
Repair Procedure 23 and 24 ................... 5-57
Repair Procedure 25 ......................... 5-57
Repair Procedure 26 ......................... 5-57
Chapter 6 Removal/Replacement
Cabinet ....................................... 6-1
Card Rack Assy ................................ 6-2
Printed Circuit Boards ........................ 6-4
Options PCBs ................................ 6-4
Main Processor Board .......................... 6-5
Disk Drives .................................. 6-7
ON/OFF Switch ................................ 6-9
Brightness and Volume Controls ............... 6-10
Monochrome CRT/Power Supply Assy .............. 6-11
Complete Assembly ........................... 6-11
Power Supply ................................ 6-12
Monochrome Deflection Board ................. 6-14
Monochrome CRT ............................. 6-15
Color CRT/Power Supply A s s y .................. 6-17
Power Supply ................................ 6-18
Color Deflection Board ...................... 6-19
Color CRT ................................... 6-21
Chapter 7 Adjustments
Monochrome CRT ............................... 7-1
Display out of Focus ........................ 7-3
Display too D i m .............................. 7-3
Display Rolls ................................ 7-4
Display too Short/Long ....................... 7-4
Display Not L i ne a r ........................... 7-5
Display too Wide/Narrow ...................... 7-5
Display Tilted ............................... 7-5
Character Field Size
......................... 7-6
Color CRT ..................................... 7-6
Horizontal Deflection ......................... 7-8
iv

Oscillator Alignment .......................... 7-8
Picture Width ................................ 7-9
Vertical Deflection ........................... 7-10
Video ...........................................7-11
Cutoff Adjustment ............................ 7-11
Whiteness ......................................7-12
Sub-Brightness ............................... 7-12
Focus ..........................................7-13
Convergence .................................. 7-13
Convergence Adjustments ...................... 7-13
Adjustments for Videotex Monitor 008-0072370 .. 7-15
Adjustments for Videotex Monitor 008-0072196 .. 7-18
Chapter 8 Strapping Information
Main Processor Board ........................... 8-1
Configuration Switches ......................... 8-1
Jumper Settings ................................ 8-5
Alternate Main Processor Board ................ 8-1
Switch Settings ............................... 8-2
Jumper Settings ................................. 8-6
Early-type Main Processor Eoard
............... 8-7
Switch Configurations of Early-type MPB ....... 8-8
Switch Configurations of PCBs
.................. 8-10
Memory Expansion Board ........................ 8-10
Alpha Display Adapter ........................ 8-1 1
Graphic Controller Boards ..................... 8-12
In-House DLC Adapter ......................... 8-13
Videotex Adapter Board ....................... 8-14
Flexible Disk Controller Board 1.2 MB .......... 8-16
Hard Disk Controller Boards .................. 8-17
Flexible Disk Drive Jumpers .................... 8-20
Appendix A Layouts and Schematics
v

Chapter 1
System Overview
NCR PERSONAL COMPUTER HARDWARE
The NCR Personal Computer consists of a main Display
Unit and a Keyboard. The computer is available in
different models, and has a variety of options that
can be added to each model. Expansion boards from
non-NCR ("third party") manufacturers can be used
with the NCR Personal Compter, as well as expansion
boards offered by NCR.
DISPLAY UNIT
The standard Display Unit consists of the following
parts:
o Cabinet
o Power Supply
o 1 or 2 flexible disk drive(s) or one flexible disk
drive and one hard disk drive
o 12-inch monochrome CRT display or 12-inch color
CRT display
o Processor Board with:
o 8088 Microprocessor
o 256 KB Random Access Memory (RAM)
o 16K Read Only Memory (ROM)
o RS-232-C Serial Interface
o Centronics Parallel Interface (for printer)
1-1

SYSTEM OVERVIEW
o Plug-in board option expansion slots
o Fixed disk drive controller plug-in board if
the unit includes a fixed disk.
o Video controller plug-in board.
A block diagram of the NCR Personal Computer Hardware
is shown in Figure 1-1.
Figure 1-1 Hardware Block Diagram
The Main Processor Board and any option boards are
1-2

SYSTEM OVERVIEW
accommodated in an easily removable Card Rack
Assembly, this assembly allows for a maximum of 7
option boards to be added to the system. The shape of
the Card Rack A ss em bl y imp os es the f ol lo wi ng
restrictions on the size of the option boards that
may be installed:
The option
dimensions:
boards must conform to the following
3 Boards 334 mm X107 DUD (13.1 in. x 4.2 in.)
3 Boards 296 mm X107 mm (11 .6 in. x 4.2 in.)
1 Board 254 mm X107 mm (10.0 in. x 4.2 in.)
MODELS
The NCR Personal Computer is available in various
models. The standard internal RAM memory size for all
models is 256KB. The models currently available are:
o A 12-inch monochrome display, 1 flexible disk
drive and 256KB memory
o A 12-inch monochrome display, 2 flexible disk
drives and 256KB memory
o A 12-inch monochrome display, 1 flexible disk
drive and 1 fixed disk drive, and a 256KB memory
o A 12-inch color display, 1 flexible disk drive
and 256KB memory
o A 12-inch color display with 2 flexible disk
drives and 256KB memory
o A 12-inch color display with 1 flexible disk
drive and a fixed disk drive, and 256KB memory
o A 12-inch color dis p lay wi t h Videot e x , 1
flexible disk drive and 256KB memory
o A 12-inch color d is pl a y with V id e ot e x , 2
1-3

SYSTEM OVERVIEW
flexible disk drives and 256 KB memory
o A 12-inch color display with Videotex, 1 flexible
disk drive and 1 fixed disk drive, and 256KB
memory
The Videotex systems are dual purpose systems, to be
used either as a Videotex system, or as a normal
personal computer. These systems are tailored to meet
indivi d ua l country req u irements , for ex amp le
Bildschirmtext for Germany, Teletel for France, and
Prestel for Great Britain.
WARNING
Disconnect the power cable before removing
the cabinet. Dangerous voltages are present
when working on the computer with the cabi
net removed.
ONLY TRAINED ENGINEERS AND NCR TRAINED SER
VICE PERSONNEL SHOULD ATTEMPT TO WORK ON THE
COMPUTER WITH THE CABINET REMOVED AND THE
POWER ON.
It is recommended that the first operation
after removing the cabinet should be to dis
charge CRT anode voltage.
CAUTION
Electrostatic discharge can cause damage to
some components used in the computer. Where
possible, work in a static free area and use
special wrist-ground straps. Avoid touching
the components and circuit paths, handle
printed circuit boards by their edges. The
construction technique (multi-layer) used on
some PC boards makes the soldering compo
nents extremely difficult, therefore such
work should only be undertaken by a field
engineer who is experienced in repairing
1-4

SYSTEM OVERVIEW
PCBs, and using the special facilities that
are available in NCR workshops.
MODEL NUMBERS
The model number of the NCR PC i»i is shown on the
plate at the back of the unit. The meaning of the
model number is shown below:
The NCR model numbers are defined in Figure 1-2.
1-5

SYSTEM OVERVIEW
Class 3277 NCR Class Number
Major Model 11 Monochrome CRT
12 Color CRT
13 Videotext CRT (Color)
Sub Model 01 Single Flexible Disk Drive
02 Dual Flexible Disk Drives
03 Fixed and Flexible Disk Drives
Voltage/ 71 120 Volts, 50/60 Hz. «)
Frequency 73 220/230/240 Volts, 50/60 Hz.
Language 00 U.S. English
01 International English
02 U.K. English
03 Spanish
05 French
06 German
09 Swedish
10 Danish
11 Norwegian
12 Italian
20 Finnish
Figure 1-2 Model Number Definition
*) The monochrome version is strapped and can be
used in the voltage range of 120/220 to 240 V.
TOOLS
A normal set of hand tool for an electronic engineer
is sufficient to service the computer. You also need
an NCR Alignment Disk.
o For 48 TPI Drives - part no. 603-9009167
1-6

SYSTEM OVERVIEW
To enable the execution of the Level 0 Loop Test the
following test adapters are available:
o Turnaround Keyboard Test Adapter 017-0044311
o TurnaroundParallel/Serial Test Adapter 017-0044320
To allow access to the Card Rack Assembly with power
applied, an extension cable can be made locally.
Figure 1-3 provides the information needed to make
the cable.
Parts Required :
Receptacle Connector (Female)
Receptacle Connector (Male)
Cable 15 Wire, 18 AWG,
Length approx. 7 0 0 m m
007-2007711
007-2007712
Local Purchase
Figure 1-3 Extension Cable
1-7

ALTERNATE MAIN PROCESSOR BOARD
Since the introduction of the NCR Personal Computer
PC4i a new style Main Processor Board, known as
"Alternate" Main Processor Board (in this manual
sometimes referred to as "Generic" Main Processor
Board) has been introduced. Much of the information
in this manual applies both to the "Alternate" Main
Processor Board and to the two Early-type Main
Processor Boards. The "Alternate" MPB is used in a
v a r i e t y of NC R c o m p u t e r s . D i s t i n g u i s h i n g
characteristics of this board are its 8 slots, 2
switch packs, VLSI ICs, RAM location and RAM
accessibility. Computers with such a mainboard
installed are marked with a "G" (which stands for
"Generic") on the PC board rack.
SYSTEM OVERVIEW
1-8

Chapter 2
Basic Troubleshooting
This chapter is intended to help the engineer in
either repairing the system, or bringing it to a
partially operative state so that the diagnostic
diskette may be used for further troubleshooting.
Presented here is a structured sequence of operations
to follow when either the system is unable to run
diagnostics, or the level 0 (power-on) diagnostics
fail (see Fig. 2-1).
Generally faulty systems can be classified into two
types:
o Non-operative - a system where it is not possible
to load a diagnostic diskette.
o Partially operative - a system with sufficient
working components to allow the loading of a
diagnostic diskette.
LEVEL 0 (POWER-ON) DIAGNOSTICS
The level 0 diagnostics are performed automatically
each time the system is switched on.
These diagnostics check the following:
o RAM memory (for memory size setting refer to
Chapter 8 "Strapping Information")
o 8088 CPU (CPU is used to test all the modules)
o 27182 EPROM (containing BIOS)
o 765 Flex Disk Controller
2-1

BASIC TROUBLESHOOTING
o 8237A DMA controller
o 8253 Timer
o 8259A Programmable Interrupt Controller
o Keyboard Interface
STEP ONE
POKER ON
Power Cords and Switches
1. Ensure that the power cord is plugged into the
back of the computer
2. Ensure that the power cord is plugged into a
properly grounded wall outlet. (Use a lamp that
you know is in working order, and check that the
outlet has power.)
3. Ensure that the power cords for any currently-
attached external devices (printer, etc.) that
have separate power cords are plugged into
properly grounded wall outlets.
4. Insert the Service Diagnostic diskette into drive
A. Use a working copy of the original diskette.
Make a back-up copy on another computer, if
necessary, but do not use a diskette that has no
backup. The possibility exists that a problem
could result in the loss of the software.
5. Turn ON any attached external devices that have
separate power cords and switches (unless the
device installation instructions specified that
the device be turned on after the computer).
6. Turn ON the computer power. Turn the volume
control and brightness to maximum.
2-2

BASIC TROUBLESHOOTING
7. Turn ON any currently-attached external devices
that were specified to be turned on after the
processing unit.
Memory Test Messages
1. In a properly operating system the turn-on
procedure results in the display of Memory Test
on the screen; quickly followed by steps through
the increments of memory installed. An audible
tone or beep is followed by the display of some
introductory messages about the software. Then
the prompt A> (or other) appears along with a
blinking cursor.
The following few steps treat anomalies of that
sequence.
a. If the screen does not display a message, the
tube may not have been warmed up in time. Wait
approx. 30 seconds for the tube to warm up.
Then turn the power OFF and ON for a retry.
2-3

BASIC TROUBLESHOOTING
Figure 2-1 Troubleshooting Flowchart
b. If there is no display after the tube is warm,
a display failure , a power supply failure, or
main processor failure is suspected. Proceed
to repair or replace as appropriate.
Make a check of the power supply voltage
before d is as se mb li ng the unit. The MPB
Parallel Port Error Codes can be checked with
2-4