Compaq Deskpro 386 - Desktop PC Manual

Foreword
Notice
The information in this guide is subject to change without notice.
COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECHNICAL OR EDITORIAL
ERRORS, OR OMISSIONS CONTAINED HEREIN; NOR FOR INCIDENTAL OR CONSEQUENTIAL
DAMAGES RESULTING FROM THE FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL.
This guide contains information protected by copyright. No part of this guide
may be photocopied or reproduced in any form without prior written consent
from Compaq Computer Corporation.
Copyright 1987, 1989 Compaq Computer Corporation.
All rights reserved. Printed in the USA.
COMPAQ, COMPAQ PORTABLE III, and COMPAQ PORTABLE 386, are trademarks of
Compaq Computer Corporation.
The software described in this guide is furnished under a license agreement
or nondisclosure agreement. The software may be used or copied only in
accordance with the terms of the agreement.
Microsoft, MS, and MS-DOS are trademarks of Microsoft Corporation.
Product names mentioned herein are for identification purposes only and may be
trademarks and/or registered trademarks of their respective companies.
COMPAQ PORTABLE 386 PERSONAL COMPUTER
MAINTENANCE AND SERVICE GUIDE
Second Edition (August 1989)
First Edition (September 1987)
Assy No. 107536-002
Binder Number 197537-001
Text Number 107538-002
Compaq Computer Corporation requires that all peripheral devices be connected
to this computer/product via shielded cables with metal RFI/EMI connector
hoods.
==============================================================================
WIRE TYPE: Multipaired, overall shielded; Belden #98XX; Alpha #54XX;
or equivalent.
CONNECTOR HOOD: RFI/EMI metal shield; AMP #74517X-X; or equivalent.
==============================================================================
It is important that the chassis ground strap of the peripheral device be
connected to the computer chassis. An Alpha #1221 flat braided strap is
sufficient. The strap is not necessary if a shielded cable connects the two
chassis.
COMPAQ PORTABLE 386 PERSONAL COMPUTER MAINTENANCE AND SERVICE GUIDE is a
troubleshooting guide that can be used as a reference when servicing the
COMPAQ PORTABLE 386 Personal Computer. Compaq Computer Corporation reserves

the right to make changes in its COMPAQ PORTABLE 386 Personal Computer without
notice. Accordingly, the diagrams and procedures in this document may not
apply to the computer you are servicing.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
CAUTION
Only trained technicians should attempt to repair this equipment. All
troubleshooting and repair procedures are detailed to allow subassembly/module
level repair only. Because of the complexity of the individual boards and
subassemblies, no one should attempt to make repairs at the component level or
make modifications to any printed wiring board. Improper repairs may create a
safety hazard. Indications of component replacement or printed wiring board
modifications may void any warranty or exchange allowances.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
CAUTION
For proper ventilation of your system, you must provide at least 3 inches
(8 cm) of clearance on all sides of the computer, except underneath.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Chapter 1. Introduction
Chapter 1.1 Summary of Text
This guide contains ten chapters which are summarized below:
Chapter 1. INTRODUCTION provides a brief summary of the contents of each
chapter in the guide, a list of needed tools and supplies, and a
list of additional reference documents.
Chapter 2. OPERATING AND PERFORMANCE SPECIFICATIONS provides operating and
performance specifications for the COMPAQ PORTABLE 386 Personal
Computer.
Chapter 3. POWER ON SELF TEST (POST)/PROBLEM ISOLATION describes the internal
system diagnostic programs that are automatically executed when
you power on the system. This chapter also provides a flowchart
for identifying and correcting problems that can occur with the
COMPAQ PORTABLE 386 Personal Computer during the Power On Self
Test procedure.
Chapter 4. SETUP AND INSPECT (See SUPPORT SOFTWARE MAINTENANCE AND SERVICE
GUIDE.)
Chapter 5. DIAGNOSTICS PROGRAM (See SUPPORT SOFTWARE MAINTENANCE AND SERVICE
GUIDE.)
Chapter 6. ERROR MESSAGES AND CODES lists the Power On Self Test and
DIAGNOSTICS Error Codes. This chapter also provides a required
course of action to resolve the problem described by each error
code.
Chapter 7. ILLUSTRATED PARTS CATALOG provides an illustrated reference for
specific COMPAQ PORTABLE 386 Personal Computer Spare Part Kit
Numbers.
Chapter 8. REMOVAL AND REPLACEMENT PROCEDURES describes how to remove and
replace field subassemblies for the COMPAQ PORTABLE 386 Personal
Computer.
Chapter 9. JUMPER AND SWITCH SETTINGS provides detailed information for
setting jumpers and switches.
Chapter 10. MASS STORAGE CONFIGURATIONS provides information on the
mass storage capabilities of the 300/600 Megabyte Fixed Disk
Drive Expansion Unit.
Chapter 1.2 Required Tools and Supplies
To service the COMPAQ PORTABLE 386 Personal Computer, you need the following
tools:
o Torx T-10 Screwdriver
o Torx T-15 Screwdriver

o Torx Angle T-15 Screwdriver
o 3/16 Inch Open End Wrench
o Integrated Circuit (IC) Removal Tool
o Integrated Circuit (IC) Insertion Tool
o Modem Terminating Plug
o DIAGNOSTICS Program
o Parallel Interface Loopback Plug
o Serial Interface Loopback Plug
Chapter 1.3 Additional Reference Information
The following documentation and related software are available to support
these and other COMPAQ computer products:
o COMPAQ PORTABLE 386 PERSONAL COMPUTER OPERATIONS GUIDE (PN 107918-001)
o COMPAQ PORTABLE 386 PERSONAL COMPUTER TECHNICAL REFERENCE GUIDE
(PN 107920-001)
o COMPAQ PORTABLE 386 PERSONAL COMPUTER MEMORY EXPANSION INSTALLATION GUIDE
(PN 107530-002)
o Installation Guides for COMPAQ Portable Computers with Plasma Displays
Mass Storage Devices (PN 107320-003)
Expansion Unit (PN 107323-003)
COMPAQ Internal Modems (PN 107325-002)
40 Megabyte Tape Drive Expansion Unit (PN 107532-002)
Second Serial Board for International Only (PN 107533-001)
o Other Installation Guides
20 MHz 80387 Coprocessor (PN 113165-002)
COMPAQ Color Monitor (PN 106223-001)
300/600 MEGABYTE FIXED DISK DRIVE EXPANSION UNIT INSTALLATION AND
OPERATIONS GUIDE (PN 115835-002)
o COMPAQ ENHANCED COLOR GRAPHICS BOARD INSTALLATION AND OPERATIONS GUIDE
(PN 106540-001)
o COMPAQ ENHANCED COLOR GRAPHICS BOARD/COMPAQ COLOR MONITOR TECHNICAL
REFERENCE GUIDE (PN 106733-001)
o Information Cards
Desktop Pedestal for COMPAQ Personal Computers with Dual Mode Plasma
Displays (PN 107326-002)
Carrying Case for COMPAQ Personal Computers with Dual Mode Plasma
Displays (PN 107327-002)

o MS-DOS Version 4 Software and Documentation (PN 114493-001 and
PN 114496-001)
o MS-DOS VERSION 3 REFERENCE GUIDE (PN 114024-001)
o BASIC VERSION 3 REFERENCE GUIDE (PN 104030-001)
o MICROSOFT Operating System/2 Standard Version 1.1
o Service Advisories and Bulletins
o HOW TO DO BUSINESS WITH COMPAQ SERVICE
o COMPAQ SERVICE QUICK REFERENCE GUIDE (PN 106854-001)

Chapter 2. Operating and Performance Specifications
Chapter 2.1 Introduction
This chapter provides operating and performance specifications for the
COMPAQ PORTABLE 386 Personal Computer (Figure 2-1).
Chapter 2.2 System Unit
Table 2-1 lists the electrical and mechanical specifications for the COMPAQ
PORTABLE 386 Personal Computer system unit.
Table 2-1. Electrical and Mechanical Specifications
==============================================================================
Dimensions:
Height 9.8 in. (24.8 cm)
Depth 7.8 in. (19.8 cm)
Width 16.0 in. (40.6 cm)
------------------------------------------------------------------------------
Weight:
Model 40 20 lb (9.1 kg)
Model 100 21 lb (9.5 kg)
Model 110 21 lb (9.5 kg)
------------------------------------------------------------------------------
Power Requirements: Domestic International
-------- -------------
Nominal Line Voltage 120 VAC 230 VAC
Range Line Voltage 102 VAC to 132 VAC 204 VAC to 264 VAC
Line Frequency 60 Hz 50 Hz
Current 3A 2A

------------------------------------------------------------------------------
AC Power Cord:
Length 6 ft (1.8 m)
Gauge 18 AWG
------------------------------------------------------------------------------
Environmental Requirements:
Temperature:
Operating 50oF to 104oF (10oC to 40oC)
Nonoperating 14oF to 122oF (-10oC to 50oC)
Shipping -22oF to 140oF (-30oC to 60oC)
------------------------------------------------------------------------------
Humidity:
Operating 20% to 80% noncondensing
Nonoperating Not less than 5% nor more than 90% noncondensing
------------------------------------------------------------------------------
Shock and Vibrations:
Shock 5 g, 11 ms, half sine (operating)
40 g 11 ms, half sine (nonoperating)
Vibration 1.0 g, 5 to 500 Hz (nonoperating)
0.15 g, 5 to 500 Hz (operating)
------------------------------------------------------------------------------
Heat Dissipation:
Minimum Configuration 35 watts 119.5 BTU/hr
Maximum Configuration 145 watts 495.1 BTU/hr
------------------------------------------------------------------------------
Maximum Unpressured Altitude:
Operating 10,000 ft (3000 m)
Nonoperating 30,000 ft (9100 m)
==============================================================================
Chapter 2.3 Portable Enhanced Keyboard
Table 2-2 lists the specifications for the portable enhanced keyboard.
Table 2-2. Keyboard Assembly Specifications
==============================================================================
Dimensions:
Height 1.2 in. ( 3.0 cm)
Depth 7.1 in. (18.0 cm)
Width 15.8 in. (40.1 cm)
Cable Length:
Compressed 8.0 in. (20.3 cm)
Extended 30.0 in. (76.2 cm)
Coil Diameter 0.6 in. (1.5 cm)
Interface Industry standard 5 pin
circular DIN type connector
==============================================================================
Chapter 2.4 Compaq Dual Mode Plasma Display
Table 2-3 lists the specifications for the COMPAQ Dual Mode Plasma Display.

Table 2-3. COMPAQ Dual Mode Plasma Display Specifications
==============================================================================
Viewing Area Dimensions:
Height 5.2 in. (13.2 cm)
Width 8.3 in. (21.1 cm)
Diagonal 10.0 in. (25.4 cm)
Weight 2.0 lb. (0.9 kg)
Graphic Resolution 640 x 400
640 x 200
320 x 200
Text Resolution 640 x 400 (80 characters x 25 lines)
==============================================================================
Chapter 2.5 1.2 Megabyte Diskette Drive
Table 2-4 lists specifications for the 1.2 megabyte diskette drive.
Table 2-4. 1.2 Megabyte Diskette Drive Specifications
==============================================================================
Dimensions:
Height 1.1 in. (2.8 cm)
Depth 8.0 in. (20.3 cm)
Width 5.8 in. (14.6 cm)
Weight 1.9 lb (0.9 kg)
Media:
Tracks per Inch 96 (1.2 megabyte format)
48 (360 Kbyte format)
Number of Tracks 80 (1.2 megabyte format)
40 (360 Kbyte format)
Data Transfer Rate 500 Kb/s (1.2 megabyte format)
300 Kb/s (360 Kbyte format)
==============================================================================
Chapter 2.6 360 KByte Diskette Drive
Table 2-5 lists the specifications for the 360 Kbyte diskette drive.
Table 2-5. 360 Kbyte Diskette Drive Specifications
==============================================================================
Dimensions:
Height 1.1 in. (2.8 cm)
Depth 8.0 in. (20.3 cm)
Width 5.8 in. (14.6 cm)
Weight 1.9 lb (0.9 kg)
Media:

Tracks per Inch 48
Number of Tracks 40
Data Transfer Rate 250 Kb/s
==============================================================================
Chapter 2.7 3 1/2 Inch 1.44 Megabyte Diskette Drive
Table 2-6 lists the specifications for the 3 1/2 inch 1.44 megabyte diskette
drive.
Table 2-6. 3 1/2 Inch 1.44 Megabyte Diskette Drive
==============================================================================
Dimensions:
Height 1.00 in. (2.5 cm)
Depth 5.91 in. (15.0 cm)
Width 4.00 in. (10.2 cm)
Weight 1.00 lb (0.45 kg)
Media: 3 1/2 inch 1.44 megabyte double sided diskette;
dual density (720 Kbyte format); high density
(1.44 megabyte format)
Tracks per Inch 135
Number of Tracks 160
Data Transfer Rate 250 Kb/s (1.44 megabyte format)
500 Kb/s (720 Kbyte format)
Average Access Time 100 ms
Rotational Speed 300 rpm
Motor Start Time 800 ms
Sectors per Track 18 (1.44 megabyte format)
9 (720 Kbyte format)
Bytes per Sector 512
==============================================================================
Chapter 2.8 40 Megabyte Fixed Disk Drive
Table 2-7 lists the specifications for the 40 megabyte fixed disk drive.
Table 2-7. 40 Megabyte Fixed Disk Drive Specifications
==============================================================================
Dimensions:
Height 1.5 in. (3.8 cm)
Depth 4.0 in. (10.2 cm)
Width 5.8 in. (14.6 cm)
Weight 1.9 lb (0.9 kg)

Drive Type
(used in SETUP program) 17 or 43
Media:
Number of Surfaces 4
Tracks per Surface 805
Number of Logical Data Heads 5
Number of Logical Cylinders 980
Average Access Time less than 30 ms
Data Transfer Rate 8 Mb/s
Interleave 1:1 for Drive Type 43
3:1 for Drive Type 17
==============================================================================
Chapter 2.9 100 Megabyte Fixed Disk Drive
Table 2-8 lists the specifications for the 100 megabyte fixed disk drive.
Table 2-8. 100 Megabyte Fixed Disk Drive Specifications
==============================================================================
Dimensions:
Height 1.6 in. (3.8 cm)
Depth 5.8 in. (14.6 cm)
Width 4.0 in. (10.2 cm)
Weight 2.9 lb. (1.9 kg)
Drive Type
(used in SETUP program) 45
Media:
Number of Surfaces 8
Tracks per Surface 748
Number of Logical Data Heads 8
Number of Logical Cylinders 748
Average Access Time less than 25 ms
Data Transfer Rate 10 Mb/s
Interleave 3:1
==============================================================================
Cha
p
ter 2.10 110 Me
g
ab
y
te Fixed Disk Drive

Table 2-9 lists the specifications for the 110 megabyte fixed disk drive.
Table 2-9. 110 Megabyte Fixed Disk Drive Specifications
==============================================================================
Dimensions:
Height 1.62 in. (4.1 cm)
Depth 5.75 in. (14.6 cm)
Width 4.00 in. (10.2 cm)
Weight 1.8 lb (0.81 kg)
Drive Type 33
(Used in SETUP program)
Number of Logical Data Heads 8
Number of Logical Cylinders 832
Average Access Time less than 25 ms
Data Transfer Rate 10 Mb/s
Sectors per Track 33
Interleave 1:1
==============================================================================
Chapter 2.11 Compaq 1200 Baud Internal Modem
Table 2-10 lists the specifications for the COMPAQ 1200 Baud Internal Modem,
which is Hayes compatible.
Table 2-10. COMPAQ 1200 Baud Internal Modem Specifications
==============================================================================
Dimensions:
Height 3.4 in. (8.6 cm)
Depth 0.7 in. (1.9 cm)
Width 5.4 in. (13.7 cm)
Type Bell 103J protocol at 300 baud
Bell 212A and CCITT V.22 protocols at 1200 baud
------------------------------------------------------------------------------
International modem specifications available locally.
==============================================================================
Chapter 2.12 Compaq 2400 Baud Internal Modem
Table 2-11 lists the specifications for the COMPAQ 2400 Baud Internal Modem,
which is compatible with the Hayes command set for asynchronous modems.
Table 2-11. COMPAQ 2400 Baud Internal Modem Specifications

==============================================================================
Dimensions:
Height 3.4 in. (8.6 cm)
Depth 0.7 in. (1.9 cm)
Width 5.4 in. (13.7 cm)
Type Bell 103J and CCITT V.21 protocol at 300 baud
Bell 212A and CCITT V.22 protocols at 1200 baud
CCITT V.22bis protocol at 2400 baud
------------------------------------------------------------------------------
International modem specifications available locally.
==============================================================================
Chapter 2.13 Expansion Unit
Table 2-12 lists the specifications for the expansion unit.
Table 2-12. Expansion Unit Specifications
==============================================================================
Dimensions:
Height 6.0 in. (15.2 cm)
Depth 2.4 in. (6.1 cm)
Width 14.5 in. (36.8 cm)
Slots Two 8/16 bit slots *
------------------------------------------------------------------------------
* Fully skirted 8 bit expansion boards will not fit.
==============================================================================
Chapter 2.14 40 Megabyte Tape Drive Expansion Unit
Table 2-13 lists the specifications for the 40 megabyte tape drive expansion
unit.
Table 2-13. 40 Megabyte Tape Drive Expansion Unit Specifications
==============================================================================
Dimensions:
Height 6.0 in. (15.2 cm)
Depth 2.4 in. (6.1 cm)
Width 14.5 in. (36.8 cm)
Media:
Tracks per Inch 83
Number of Tracks 20
Data Transfer Rate 500 Kb/s
==============================================================================
Chapter 2.15 Power Supply
Table 2-14 lists the specifications for the power supply.

Table 2-14. Power Supply Specifications
==============================================================================
Input Requirements:
Line Voltage 120/230
Line Fuse 3A at 120, 2A at 230
Line Frequency 47/62 Hz
------------------------------------------------------------------------------
Power:
Steady State 165 watts
Peak State 180 watts
------------------------------------------------------------------------------
Cooling Forced air via 12 VDC fan
------------------------------------------------------------------------------
VDC Output:
Nominal
Continuous Maximum
Nominal Current Current Peak Regulation
Voltage Minimum Maximum Current Tolerance
------------------------------------------------------------------------------
+5.0 VDC 3.0A 14.3A 3%
+12.0 VDC 1.0A 3.0A 5.0A 5%
-12.0 VDC 0.0 0.56A 1.0A 5%
+200.0 VDCI 0.0 0.16A ñ 5 VDC
5.0 VDCI 0.0 0.06A 5%
------------------------------------------------------------------------------
NOTE: These values are maximum values based on nominal operating conditions
for temperature, line voltage, frequency, and altitude. Also, a minimum load
of +12 VDC must be maintained for proper power supply operation.
==============================================================================
Chapter 2.16 300/600 Megabyte Fixed Disk Drive Expansion Unit
Table 2-15 lists the specifications for the 300/600 Megabyte Fixed Disk Drive
Expansion Unit.
Table 2-15. 300/600 Megabyte Fixed Disk Drive Expansion Unit Specifications
==============================================================================
Dimensions:
Height 6.4 in. (16.1 cm)
Depth 16.5 in. (41.9 cm)
Width 14.5 in. (35.9 cm)
------------------------------------------------------------------------------
Weight:
300 Megabyte Unit 27.5 lb (12.4 kg)
600 Megabyte Unit 35.5 lb (15.9 kg)
------------------------------------------------------------------------------
Environmental Requirements:
Temperature:
Operating Not less than 50oF or more than 104oF
(10oC to 40oC)
Nonoperating Not less than 50oF or more than 104oF
(10oC to 40oC)
Shipping Not less than -22oF or more than 140oF
(-30oC to 60oC)
Humidity:
Operating Not less than 20% or more than 80%

(noncondensing)
Nonoperating Not less than 5% or more than 90% (noncondensing)
------------------------------------------------------------------------------
Controller 1:1 interleave buffered ESDI external fixed disk
drive controller board installs in one 8/16 bit
expansion slot in the system unit.
------------------------------------------------------------------------------
External Interface
Adapter External interface adapter supports one or two
300 megabyte fixed disk drives
------------------------------------------------------------------------------
LED Indicator Green
------------------------------------------------------------------------------
Power Requirements: U.S. International
---- -------------
Nominal Line Voltage 120 VAC, 60 Hz 230 VAC, 50 Hz
Range Line Voltage 102 VAC to 132 VAC 204 VAC to 264 VAC
Line Frequency 47 to 63 Hz 47 to 63 Hz
------------------------------------------------------------------------------
Power 192 watts (steady state)
220 watts (peak power)
------------------------------------------------------------------------------
Current 5A (fuse rating) 4A (fuse rating)
------------------------------------------------------------------------------
Power Cable:
Length 78 in (2.0 m)
Interface NEMA 5-15P (U.S.)
------------------------------------------------------------------------------
Signal Cable:
Length 60 in. (1.52 m)
Type 44 lead twisted pair
Connectors 44 pin subminiature D - shell (2)
==============================================================================

Chapter 3. Power On Self Test (POST)/Problem Isolation
Chapter 3.0 Introduction
This chapter lists the assemblies checked by the Power On Self Test (POST) and
briefly describes the types of error codes that can occur. The chapter also
includes problem isolation procedures and a flowchart for quick reference.
Chapter 3.1 POST
POST is a series of diagnostic tests that automatically run on the COMPAQ
PORTABLE 386 Personal Computer when the system is turned on.
POST checks the following assemblies to ensure that the computer system is
functioning properly:
o Keyboard
o Power supply
o System board
o Display controller board
o Memory expansion boards
o Memory
o Diskette drives
o Fixed disk drives
POST also detects the type of mass storage devices installed in the computer.
If POST finds an error in the system, an error code results. The error code
can be audible, visual, or both. See Chapter 6, "Error Messages and Codes,"
for an explanation of error codes.
Chapter 3.2 Preliminary Steps to Problem Isolation
If you encounter an error condition, complete the following steps before
starting problem isolation procedures:
1. Turn off the computer.
2. Disconnect the AC power cord from the AC outlet.
3. Disconnect the signal cables of any peripheral devices from the
computer.
4. Remove any boards not manufactured by Compaq.
5. Install a loopback plug connector in both the parallel interface and the
serial interface. If you have a COMPAQ Internal Modem, install a modem
terminating plug in the modem RJ11 jack.
NOTE: To test your printer during the printer test or log errors to a

printer, remove the loopback plug from the parallel interface and connect the
printer instead.
6. Reconnect the AC power cord to a well grounded AC outlet.
7. Insert the latest version of the COMPAQ DIAGNOSTICS diskette into Drive A
(Drive Position 1), and push in on the drive button.
8. Turn on the computer.
See the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for detailed
information on problem isolation.
Chapter 3.3 Problem Isolation Flowchart
The problem isolation flowchart provides a quick reference for identifying and
correcting problems that may occur during POST. The flowchart gives
troubleshooting procedures for identifying malfunctions. It also directs you
to the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE and to Chapter 6, "Error
Messages and Codes," for more detailed troubleshooting information.

Chapter 4. Setup and Inspect
Chapter 4.0 Introduction
Please consult the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for current
information on SETUP and INSPECT.