NCR PC4I User manual

( Personal
Computer
PC4i
Service Manual

March 1986
Copyright c 1986 by NCR Corporat i on
Dayton . Ohio
All Rights Reserved
Pr inted in the Federal Republic of Germa ny
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 NCRoffice for information
that is applicable and current.
C
C
C

C
C
C
NCR PERSONAL COMPUTER PC 4i
SERVICE MANUAL
CONTENTS
Chapter 1 System Overview
NCR Personal Computer Hardware
Display Unit .................................. .
t-!odels ................................ · · .. · · · · ·
lliodel r,Jumbers •..•...•.•..•.•...•••••..•..••.•.•
Tools ............................ , ........ · · · ·
Alternate Main Processor Board .......•....••..•
Chapter 2 Basic Troubleshooting
Level O (Power-On) Diagnostics
Power On •...•..•...••.•••....•.•..•.........•.
Power Cords and Switches ...•...•..•...•.••••.••
Memory Test Messages •.••..••••.••...•..••.•••.
After First Attempt .•........•.......•.••....•
After Second Attempt ..•.........•.....••••.•••
Power Supply ...............•.................••
l)eripherals ................................... .
Check Keyboard ......•.........•...••.•.•••.....
Check for Diagnostic Errors •.•..•...••••....•..
Restore Full Configur·ation ••••.••...•....•••.•.
Test Total Memor·y ..•..••..•..•....•••...••.•..
Test CRT and Disk Drives •...•..•....••••......
Re-Installation ...••.•.•...............•..•.••.
Chapter 3 Level O Diagnostics
Memory Test ...•..•...•••.•.••......•••..•.•...•.
Other• MPB Tests •...•.•.••...•..••....••.••••••..
r:eyboar·d Test .................................. .
Initialization and Loading •••.••..••.•.•..•.•...
Er. ror Returns .................................. .
Parallel Port Error Codes ..•.............••.•..•
Level O Loop Tests on Generic Processor Board ••
Error Messages of the Early-Type MPB ••••..•.••.
Suggested Action .......•..•.....•....•......••.
1-1
1-1
1-3
1-5
1-6
1-8
2-1
2-2
2-2
2-3
2-6
2-7
2-9
2-17
2-17
2-17
2-19
2-19
2-20
2-22
3-1
3-5
3-5
3-5
3-6
3-7
3-7
3-14
3-15
i

Chapter 4 Level 1 Diagnostics
How to Begin Testing .......................... .
Load the Diskette
Main Menu
Main Menu Help Screens ••••••.•..••••.••.•....••
Test Completion Displays •.••.•••••.••.••...••..
Diagnostic Selections ••••.••.••.•.•.••••••.•...
Run all Tests Once ........................... .
Automatic Completion ••••••.•.•.••••.•••.......
Memory (Main Menu Selection 1) •••.•..•••••••••
Memory Test Help Screens ••.•..•.....•.••.•••..
RAM Pat tern Test ..•••........•................
RAM Address Test ••••••••.••.••••..••••.•.•••.•
RAM Parity Test ••....•.....•..............•..
RAM Walking Ones Test •••....••.•....••...•••.•
Firmware Checksum Test ••••..•••...••.•...•....
Controllers (Main Menu Selection 2) •••.....•.••
Controllers Test Help Screens ••.....•.•••.••••
CPU Test ••••••.•..••••••••....•.•••••••......•
DMA Test ..•••••••••.••.••••••.•...•••..•...•••
Flexible Disk Controller Test •.....••••.•.••••
Interval Timer Test •.•.•.......••.•....•••..•.
Interrupt Controller Test ....•............•...
CPU Controller Test ••••.•.•.••.•••.••...•.....
Monochrome Display Controller Test •...•.•.••..
Color Graphics Display Controller Test .••.•.•.
Serial Synchronous Controller Test •.•.•.•.•••.
Keyboard (Main Menu Selection 3) .............. .
Flexible Disk Drive (Main Menu Selection 4) .•.•
Flexible Disk Drives HELP Screens •.••.........
Read Only Drive A Test •••••.••.•...•..••.••.••
Read/Write Drive A Test •.•.•••••••••••........
4-1
4-1
4-2
4-5(
4-6
4-8
4-9
4-9
4-11
4-12
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-18
4-19
4-20
4-21 (
4-22
4-23
4-24
4-23
4-26
4-26
4-28
4-28
4-29
4-30
4-31
Fixed Disk Drive (Main Menu Selection 5) •..•••
Fixed Disk Drive Test HELP Screen .•••••.•.•..•
4-32
Read/Write Maintenance Track •••••••.••••...••. 4-32
Read Only Sector O .••.••.•..•..•..•••••••..•.• 4-33
Read Only Entire Disk •••••.••••••••••••••.•.•• 4-34
Read/Write Entire Disk ••••.••••••••••••••.••.. 4-35 l'
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
ii

C
0
Printer Tests .........................•.......
Generic Printer Test . ........................ .
PC Compatible Printer Test ••••.•.•••••••.••••.
Utilities ..................................... .
Videotex Adapter Tests (Main Menu Selection) •...
Local Test ................................... .
Remote Test
Picture Test ................................. .
Chapter 5
Level 1 Diagnostic Error Returns
4-50
4-51
4-52
4-53
4-54
4-55
4-55
4-57
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 CodeG and
Repair Procedures ••..•••.••...•.•••.•••••.•..••
Format of Displayed Error Codes ..•.••.•••••••.
List of Major Error Codes •••••••••••.••....•..
Memory Error Codes •..•..•••••••..••..•••......
Repair Procedure 01 ...•••..•....•.••••.•..•..
Repair Procedure 02 •.••.••......•..•..•..••..
Repair Procedure 03 .••••••.•••..•••.••••.••.
Repair Procedure 04 ••••.••••••.•.•.••••.••.•
Repair Procedure 05 •••••.••••..•.••..••••••.
Flexible Disk Drive Error Codes •.••.••••••••••
Repair Procedure 06 .•.••.••.•.•.•.••.•••..•••
Keyboard Errol' Codes ..••...••.••...••..••••••.
Repair Procedure 07 ......................... .
Video Display Error Codes .•......•.••••.••..••
Repair Proceduce 08 ••••.•••••.•••.•.•••••••..
Repair Procedure 09 ..••...••.••..•••••••.••..
Peripheral Error Codes •..••••••..••..••••... ,.
Repair Procedure 10 ••..•..••...••...••••••••
Repair Procedure 11 .••.•••..••••••••.••••••.
Repair Procedure 12 .••.••••.•...••••.••..•••
Major System Controller Error Codes •••.•...•••
Repair Procedure 13 ...•..•••.•....•..••...•..
Repair Procedure 14 •...•...•••..•...••••••••.
Repair Procedure 15 •.••...••.........•••.••..
Repair Procedure 16 •.••..•.•••..•••.••••...•.
Repair Procedure 17 ........................ .
5-8
5-10
5-10
5-12
5-13
5-18
5-20
5-21
5-21
5-23
5-25
5-32
5-32
5-34
5-35
5-37
5-38
5-40
5-43
5-46
5-39
5-47
5-48
5-48
5-49
5-50
iii

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

C
C
C
Dseillator Alignment .........••••....•..••.... 7-8
Picture Width • . . . . . • . . . • •• . . • • • •. • . . . . . • • . . . • 7-9
Vertical Deflection ....•••.••••••..••••••••••. 7-10
Video .......................................... 7-11
Cutoff Adjustment •••••••••.••.•••..••••••..•.. 7-11
~lhiteness ..................................... 7-12
Sub-Brightness .••..•••..••.. , . . . • • . • . • . . . . •. • . 7-12
FOCU!::> .......................................... 7-13
Convergence ................................... 7-13
Convergence Adjustments ....................... 7-13
Adjustnents for Videotex Monitor 008-0072370 7-15
Adjustments for Videotex Monitor 008-0072196 .• 7-18
Chapter 8 Strapping Inf'ormation
Main Processor Board .......................... .
Configuration Switches ••••..••.•••.••.••..•••••
Jumper Settings ............................... .
Alternate Main Processor Board .•...••..•••.••.
Switch Set tings ............................... .
Jumper Settings ............................... .
Early-type Main Processor Board ••••••••••••••••
Switch Configurations of Early-type MPB •...•.••
Switch Configurations of PCBs ••••••••••••••.•••
Memory Expansion Board ••••.•••••••••••••••••••
Alpha Display Adapter •••••.•••••••••••••••••••
Graphic Controller Boards •••..•.••••••••••••.•
In-House DLC Adapter .••••••••.••.•.•••••••••..
Videotex Adapter Board •••••••••••.•••.••••.••
Flexible Disk Controller Board 1.2 MB •.••.•••••
Hard Disk Controller Boards
Flexible Disk Drive Jumpers •.•••••••••.•••.••••
Appendix A Layouts and Schematics
8-1
8-1
8-5
8-1
8-2
8-6
8-7
8-8
8-10
8-10
8-11
8-12
8-13
8-14
8-16
8-17
8-20
V

C
C

C
C
(_
Chapter 1
System Overview
RCR PERSORAL 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 (nthird partyn) manufacturers can be used
with the NCR Personal Compter, .as well as expansion
boards offered by NCR.
DISPLAY URIT
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

SY STEM OVERVIEW
o Plug-in board option expansion slots
0 Fixed disk drive controller plug.in board if
the unit includes a fixed disk.
0 Video controller plug-in board. (
A block diagram of the NCR Personal Computer Hardware
is shown in Figure 1-1.
MAIN
MEMOAY
15'11(1
"'"""
1
S'-"'"'LY
l -
.,
2
i
I!?
-
0 3
.,
I
..
! -
~
I 4
"
,._
a 5
, ....
8
"""
,._
: a
..
;;
--
~
1
K(YIOAAD
CONNECTOR
CAT
srt:AKEA
MOHOCHAOUE
IHTlNS1TY
..
COLOA
SERIAL 1/F
IAO • IIOOPIJCEL
Al 232C
PAAALUl
,,.
.....
HE•
DISK DISK
:IOOKI
3IOKI
Figure
}
MO
r------, 6'0KI
IMEMORY E>cl'ANSION I
tolMKII
lJl!_?7..:_ K~~t~I_ J
GRAPHICS
CONTAOl.LER l2KI
r .. LP~- --,
1 CONTAOU.1 A ;
~~,..:.~'~J
FIJCED DISK
CONTROLLER
IJ217-1JCOl0flillVI
KEYIIOAAD
r;:-----,
,n--=__rt,
,LI --,
L1~.1!..:~lliK..!1!!J
r.------,
,n--=-"',
,LI --,
L_t~7!. ~~-J
or Fllll:ED
DISK
, .....
r--------,
I GRAPHICS CONTROLLER 1
-1EXPANSl0fr\lto .. KI I
I 13211 • KSl11 I
.._ _______ .J
r-----,
I TILT/SWIVEL I
13211 • KJOOI I
L ____ J
r------,
1 tN HOUSE DLC COMM t
J 1/F AOAPTlA I
113217 · UOtl I
'--------..J
,----------,
I COLOR/GRAPHICS I
I AO,OTIE.A I
I tl1M-Kl«U l
I ~====~ I
I MONOCHROME I
I ADAPTER I
I ll294-Kl411 I
:_ _________ J
1-1 Hardware Block Diagram
The
Main Processor Board and any option boards are
1-2

C
C
(
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 Assembly imposes the following
restrictions on the size of the option boards that
may be installed:
The option
boards must conform to the following
dimensions:
3
Boards
334
mm X 107 mm (13.1 in. X 4.2
in.)
3
Boards
296 mm X 107
mm ( 11 .6
in. X 4.2
in.)
1 Board 254 mm X 107 mm
( 10 .o
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:
0 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
0 A
12-inch color display with 1 flexible disk
drive and a fixed disk drive, and 256KB memory
o A 12-inch color display with Videotex , 1
flexible disk drive and 256KB memory
o A
12-inch color display with Videotex, 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
individual country requirements, for example
Bildschirmtext for Germany, Teletel for France, and
Prestel for Great Britain.
1-4
VARRiliG
Disconnect the power cable before removing
the cabinet. Dangerous voltages are present
when working on the computer with the cabi-
net removed.
ONL y TRAINED ENGINEERS AND NCR TRAINED SER- C
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

C
C
l
SYSTEM OVERVIEW
PCBs, and using the special facilities that
are available in NCR workshops.
MODEL NUMBERS
The model number of the NCR PC 4i is shown on the
plate at the back of the unit. The meaning of the
model number is shown below:
3277-XX XX-XX XX
T -[__ Language
(_Voltage/Frequency
'------Sub Model
"--------Major Model
Class
The NCR model numbers are defined in Figure 1-2.
1-5

SY STEM OVERVIEW
Class
Major Model
Sub Model
Voltage/
Frequency
Language
3277
11
12
13
01
02
03
71
73
00
01
02
03
05
06
09
10
11
12
20
NCR Class Number
Monochrome CRT
Color CRT
Videotext CRT (Color)
Single Flexible Disk Drive
Dual Flexible Disk Drives
Fixed and Flexible Disk Drives
120 Volts, 50/60 Hz. *)
220/230/240 Volts, 50/60 Hz.
U.S. English
International English
U.K. English
Spanish
French
German
Swedish
Danish
Norwegian
Italian
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
C

SYSTEM OVERVIEW
To enable the execution of the Level O Loop Test the
following test adapters are available:
o Turnaround Keyboard Test Adapter
017-0044311
C o TurnaroundParallel/Serial Test Adapter 017-0044320
C
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. 700mm
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
007-2007711
007-2007712
Local Purchase
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Figure 1-3 Extension Cable
1-7

SYSTEM OVERVIEW
ALTERlflTE KAIB 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
variety of NCR computers. Distinguishing
characteristics of this board are its 8 slots, 2
switch packs, VLSI !Cs, 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.
1-8
C

C
C
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 O (power-on) diagnostics
fail (see Fig. 2-1).
Generally faulty systems can be classified into two
types:
0 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 O (POWER-OH) DIAGNOSTICS
The level O diagnostics are performed automatically
each time the system is switched on.
These diagnostics check the following:
0
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 ORE
POWER OR
Power Cords and Switches
1. Ensure that the power cord is plugged into the
back of the computer
2.
3.
4.
5.
6.
2-2
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.) (
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.
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.
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).
(
Turn ON the computer power. Turn the volume
control and brightness to maximum.

C
C
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 TROUBLRSHOOTING
2-4
Go10S...tu
o....-a11ic1
Md, .....,
PortErn,,CCldN
Go IOS9',,tC•
Oiagnos1ia
Md ........
'onEnorCodN
-Off
...,...,.,.E•s-"111-
.,_,,
Set Slllltdla
··-
Go10S.NIH
Diagnmtia Md I
orr..u.,ron
ErrotCodN
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
before disassembling the
Parallel Port Error Codes can
supply voltage
unit. The MPB
be checked with
C