Compaq PORTABLE 286, COMPAQ PORTABLE, COMPAQ PLUS Maintenance And Service 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 document contains proprietary information protected by copyright. No
part of this document may be photocopied or reproduced in any form with out
prior written consent from Compaq Computer Corporation.

Copyright 1986 by Compaq Computer Corporation.
All rights are reserved.

COMPAQ, COMPAQ PLUS and COMPAQ PORTABLE 286 are registered trademarks and
COMPAQ PORTABLE II is a trademark of COMPAQ Computer Corporation.

The software described in this document is furnished under a license
agreement of nondisclosure. The software may be used or copied only in
accordance with the terms of the agreement. It is against the law to copy
Microsoft BASIC or MS-DOS onto cassette tape, fixed disk drive, diskette, or
any other medium for any purpose other than the purchaser's personal use.

Copyright 1981, 1982, 1983, 1984, 1985, and 1986 by Microsoft Corporation.

MS-DOS is a registered trademark of Microsoft Corporation.

MAINTENANCE AND SERVICE GUIDE
COMPAQ PORTABLE COMPUTER
COMPAQ PLUS PERSONAL COMPUTER
COMPAQ PORTABLE 286 PERSONAL COMPUTER

Second Edition (April 1986)
Assembly Number 102901-001
Binder Number 102900-001
Text Number 102973-001

Compaq Computer Corporation 90 Day Limited Warranty

Compaq Computer Corporation (Compaq) warrants the products that it
manufactures to be free from defects in materials and workmanship for a period
of 90 days from the date of purchase from Compaq or an Authorized COMPAQ
Computer Dealer. This warranty is limited to the original purchaser
(Purchaser) of the product and is not transferable.

During the 90 day (ninety day) warranty period, Compaq will repair or replace
with new or refurbished parts, at its option, any defective parts at no
additional charge, provided that the product is returned, shipping prepaid, to
Compaq or an Authorized COMPAQ Computer Dealer. The Purchaser is responsible
for insuring any product so returned and assumes the risk of loss during
shipping. All replaced parts and products become the property of Compaq.

Dated proof of purchase must be provided by the Purchaser when requesting that
warranty work be performed. The Purchaser may request information on how to
obtain warranty service by contacting an Authorized COMPAQ Computer Dealer or
writing to Compaq Computer Corporation for further information.

This limited warranty does not extend to any products that have been damaged
as a result of accident, misuse, abuse, non Compaq modification, or as a
result of service by anyone other than Compaq or an Authorized COMPAQ Computer
Dealer.

Except as expressly set forth above, no other warranties are expressed or
implied, including, but not limited to, any implied warranties of
merchantability and fitness for a particular purpose, and Compaq expressly
disclaims all warranties not stated herein in the event the product is not
free from defects as warranted above, the purchaser's sole remedy shall be
repair or replacement as provided above. Under no circumstances will Compaq
be liable to the purchaser or any user for any damages, including any
incidental or consequential damages, expenses, lost profits, lost savings, or
other damages arising out of the use of or inability to use the product.

Some states do not allow the exclusion of limitation of incidental or
consequential damages for consumer products, and some states do not allow
limitations on how long an implied warranty lasts, so the above limitations or
exclusions may not apply to you.

This warranty gives you specific legal rights, and you may also have other
rights that vary from state to state.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

WARNING

This equipment has been certified to comply with the limits for a Class B
computing device, pursuant to Subpart J of Part 15 of FCC Rules. Only
peripherals (computer input/output devices, terminals, printers, and so on.)
certified to comply with the Class B limits may be attached to this computer.
Operation with noncertified peripherals is likely to result in interference to
radio and TV reception.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

WARNING

This equipment generates, uses, and can radiate radio frequency energy. If
not installed and used in accordance with the manufacturer's instructions, it
may cause interference with radio and television reception. This equipment
has been certified to comply with the limits for a Class B computing device,
pursuant to Subpart J of Part 15 of FCC Rules, which are designed to provide
reasonable protection against such interference. If this occurs, the user
will be required to take whatever measures may be necessary to eliminate the
interference. In attempting to do so, the user should:

o Reorient the receiving antenna.

o Relocate the computer with respect to the receiver with which it

interferes.

o Plug the computer into a different AC outlet so that the computer and the

receiver with which it interferes are on different branch circuits.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

If necessary, the user should consult an Authorized COMPAQ Computer Dealer or
any experienced radio/television technician for additional suggestions.

Compaq Computer Corporation requires that all peripheral devices be connected
to this computer 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 #745l7x-x; or equivalent.

It is important that the chassis ground of any peripheral device be connected
to the computer chassis. An Alpha #1221 flat braided strap is sufficient.
This strap is not necessary if the shielded cable connects the two chassis.

Preface

The Maintenance and Service Guide is a troubleshooting, maintenance, and
repair guide that can be used as a reference when servicing the COMPAQ
Portable Computer, the COMPAQ PLUS Personal Computer, and the COMPAQ
PORTABLE 286 Personal Computer.

All troubleshooting and repair procedures are detailed to allow subassembly/
module level repair only.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Because of the complexity of the individual boards and subassemblies, Compaq
Computer Corporation strongly recommends that you do not attempt to make field
repairs at the component level. Indications of this may void any warranty or
exchange allowances.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Summary of Text

The Maintenance and Service Guide contains the following eight chapters.

Chapter 1 "Operating and Performance Specifications" provides operating and

performance specifications for the COMPAQ Portable, the COMPAQ
PLUS, and the COMPAQ PORTABLE 286 Personal Computers.

Chapter 2 "Power On Self Test (POST)/Problem Isolation" describes the

internal system diagnostics programs that are automatically
executed when you turn on the system. A flowchart is provided for
quick reference for identifying and correcting problems that may
occur during the Power On Self Test procedure.

Chapter 3 "SETUP" describes how to configure the system and defines the

system prompts.

Chapter 4 "DIAGNOSTIC Procedures" describes the use and function of the'

COMPAQ DIAGNOSTIC Program Version 3. The text provides a detailed
description of the various diagnostic routines and how to execute
them.

Chapter 5 "Error Messages and Codes" lists and describes the Power On Self

Test (POST) and DIAGNOSTICS Error Codes. It also provides required
action for resolving each problem described by the corresponding
error code.

Chapter 6 "Illustrated Parts Catalog" contains illustrated parts breakdowns,

order numbers, and part names for the COMPAQ Portable, the COMPAQ
PLUS, and the COMPAQ PORTABLE 286 Personal Computers.

Chapter 7 "Removal and Replacement Procedures" describes how to remove and

replace subassemblies for the COMPAQ Portable, the COMPAQ PLUS, and
the COMPAQ PORTABLE 286 Personal Computers.

Chapter 8 "Jumper Settings, Switch Settings, and Adjustments" provides

detailed information for setting jumpers and switches. It also
provides instructions for adjusting the video display unit and the
diskette drive speed.

Required Tools and Supplies

To service the COMPAQ Portable, COMPAQ PLUS, and COMPAQ PORTABLE 286 Personal
Computers, you need:

o 1/4 inch slotted blade screwdriver (COMPAQ Portable and COMPAQ PLUS

Personal Computers only)

o COMPAQ DIAGNOSTICS Diskette Version 3 (PN 102971-001 *)

o Formatted Scratch Diskette(s)

o Printer loopback plug 25 pin (PN 100755-001)

o Serial loopback plug 25 pin (PN 100754-001)

o 9 pin serial loopback plug (PN 102999-001)

o Torx T-15 screwdriver

o Torx T-10 screwdriver

o 1/4 inch nut driver

o No. 2 Phillips screwdriver

o 5/16 inch Box end wrench

Optional Tools are:

o Digital voltmeter
o Memory chip (integrated circuit) insertion tool
o Memory chip (integrated circuit) removal tool

o Diskette drive signal extension cable (PN 100546-001)
o Diskette drive power extension cable (PN 100545-001)
o Special Service Tool Kit (PN 101089-001) containing:

- Power Supply socket adjustment tool

- T-10 socket

- 3/16 inch socket

- 5/16 inch adjustable socket

Additional Information

The following documentation and related software are available to support
these and other COMPAQ computer products.

Associated Documentation:

o COMPAQ PORTABLE COMPUTER OPERATIONS GUIDE (PN 100001-001)
o COMPAQ PLUS PERSONAL COMPUTER OPERATIONS GUIDE (PN 100633-001 *)
o COMPAQ PORTABLE 286 PERSONAL COMPUTER OPERATIONS GUIDE (PN 101770-001 *)
o AUTHORIZED DEALER GUIDE (PN 100003-001)
o MS-DOS VERSION 2 REFERENCE GUIDE (PN 100631-002 *)
o MS-DOS VERSION 3 REFERENCE GUIDE (PN 102631-001 *)
o BASIC VERSION 2 REFERENCE GUIDE (PN 100632-001 *)
o BASIC VERSION 3 REFERENCE GUIDE (PN 102740-001)
o 80286 BASED PRODUCTS TECHNICAL REFERENCE GUIDE (PN 102786-001)

* Part number no longer available.

Chapter 1. Operating and Performance Specifications

Chapter 1.1 Introduction

This section provides operating and performance specifications for the COMPAQ
Portable and the COMPAQ PLUS in Table 1-1, and the COMPAQ PORTABLE 286
in Table 1-2.

Specifications for the COMPAQ Portable and COMPAQ PLUS Personal Computer are:

o Electrical and mechanical
o Environmental
o Keyboard
o Video display
o 360 Kbyte diskette drive
o 10 megabyte fixed disk drive
o Power supply

Specifications for the COMPAQ PORTABLE 286 Personal Computer are:

o Electrical and mechanical
o Environmental
o Keyboard
o Video display
o 20 megabyte fixed disk drive
o 10 megabyte tape drive
o 1.2 megabyte diskette drive
o 360 Kbyte diskette drive
o Power supply

Table 1-1. COMPAQ Portable and COMPAQ PLUS Personal Computers Operating and
Performance Specifications
==============================================================================
Electrical and Mechanical Specifications

-----------------------------------------------------------------------------­Dimensions:

Height 8.5 in. (215.9 mm)
Depth 16.0 in. (406.4 mm)
Width 20.0 in. (512.8 mm)

Weight:

With one diskette drive 27.5 lb (12.5 kg)

With two diskette drives 30.5 lb (13.5 kg)

With one diskette drive
and one fixed disk drive 31 lb (14 kg)

Power Requirements:

Line Voltage 115 VAC
Line Frequency 60 Hz

Power

Current 3 amps

Power Cable:

Length 79 in. (2006.6 mm)
Gauge 18 AWG

Environmental Requirements:

Temperature:

Operating 50oF to 104oF (10oC to 40oC)
Nonoperating 32oF to 140oF (0oC to 60oC)

Humidity:

Operating 20% to 80% (noncondensing)
Nonoperating 5% to 90% (noncondensing)

-----------------------------------------------------------------------------­Keyboard Specifications

-----------------------------------------------------------------------------­Dimensions:

Height 1.5 in. (38.1 mm)
Depth 7.06 in. (179.3 mm)
Width 18.25 in. (463.6 mm)

Number of Keys 83

Keyboard Cable:

Length 72 in. (1828.8 mm)
Gauge 28 AWG

-----------------------------------------------------------------------------­Video Display Specifications

-----------------------------------------------------------------------------­Display:
o Nine inch diagonal, 90 degree deflection
o High persistence green phosphor
o Etched surface to reduce glare
o 80 character by 25 line screen
o 40 character by 25 line screen
o 640 x 200 dot resolution, graphics
o 320 x 200 dot resolution, graphics
o 720 x 350 dot resolution, text

-----------------------------------------------------------------------------­360 Kbyte Diskette Drive Specifications

-----------------------------------------------------------------------------­Dimensions:

Height 1.625 in. (40.625 mm)
Depth 8.29 in. (210.6 mm)
Width 5.88 in. (149.4 mm)

Weight 3.2 lb (1.45 kg)

Data Transfer Rate 250 Kb/s

Media 48 TPI Double Sided Double Density Diskettes

Number of Tracks 40

Tracks per Inch 48

-----------------------------------------------------------------------------­10 Megabyte Fixed Disk Drive Specifications

-----------------------------------------------------------------------------­Dimensions:

Height 1.69 in. (4.33 cm)
Width 5.875 in. (14.6875 cm)
Depth 8.25 in. (20.625 cm)

Weight 3.5 lb (1.575 kg)

Media Fixed plated media

Tracks per Inch 600

Number of Cylinders 305

Data Transfer Rate 5 Mb/s

Average Access Time 105 ms

-----------------------------------------------------------------------------­Power Supply Specifications

-----------------------------------------------------------------------------­Input Requirements:

AC Voltage RMS:

Domestic 102 - 132 VAC

International 204 - 264 VAC
Line Frequency 47 to 62 Hz
Line Voltage 120 VAC, 60 Hz
Current 2 amps maximum at input

(3 amps depending on fuse rating)

-----------------------------------------------------------------------------­VDC Output: Nominal Current Current Regulation

Voltage Amps Amps Tolerance
VDC Minimum Maximum * Percent

-----------------------------------------------------------------------------­+ 5.0 2.0 10.0 5

- 5.0 0.0 0.5 5
+ 12.0 1.0 5.0 5

- 12.0 0.0 0.5 5

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

* These values are maximum values based on nominal operating conditions for

temperature, line voltage, line frequency, and altitude.

==============================================================================

Table 1-2. COMPAQ PORTABLE 286 Personal Computer Operating and Performance
Specifications
==============================================================================
Electrical and Mechanical Specifications

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

Dimensions:

Height 8.5 in. (215.9 mm)
Depth 16 in. (406.4 mm)
Width 20 in. (508.0 mm)

Weight:

Model 1 30 lb (13.5 kg)
Model 2 33 lb (15.0 kg)
Model 3 34 lb (15.4 kg)

Power Requirements:

Line Voltage 115 VAC
Line Frequency 60 Hz

Power

Current 4 amps

Power Cable:

Length 72 in. (1828.8 mm)
Gauge 18 AWG

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

Environmental Requirements

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

Temperature:

Operating 50oF to 104oF (10oC to 40oC)
Nonoperating 32oF to 140oF (0oC to 60oC)

Humidity:

Operating 20% to 80% (noncondensing)
Nonoperating 5% to 90% (noncondensing)

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

Keyboard Specifications

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

Dimensions:

Height 1.5 in. (38.1 mm)
Depth 7.06 in. (179.3 mm)
Width 18.25 in. (436.6 mm)

Number of Keys 84

Keyboard Cable:

Length 72 in. (1828.8 mm)
Gauge 28 AWG

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

Video Display Specifications

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

Display:
o Nine inch diagonal, 90 degree deflection
o High persistence green phosphor
o Etched surface to reduce glare
o 80 character by 25 line screen
o 40 character by 25 line screen
o 640 x 200 dot resolution, graphics
o 320 x 200 dot resolution, graphics
o 720 x 350 dot resolution, text

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

20 Megabyte Fixed Disk Drive Specifications

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

Dimensions:

Height 1.7 in. (4.33 cm)
Depth 4.1 in. (10.41 cm)
Width 5.75 in. (14.61 cm)

Weight 1.8 lb (0.8 kg)

Media Fixed plated media

Number of Data Heads 4

Number of Cylinders 615

Average Access Time 105 ms (maximum)

Data Transfer Rate 5 Mb/s

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

10 Megabyte Tape Drive Specifications

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

Dimensions:

Height 1.65 in. (4.29 cm)
Depth 8 in. (20 cm)
Width 5.65 in. (14.76 cm)

Weight 1.7 lb (0.765 kg)

Media DC 1000 Manufactured by 3M Corporation or

equivalent

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

1.2 Megabyte Diskette Drive Specifications

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

Dimensions:

Height 1.65 in. (4.29 cm)
Depth 8.25 in. (20.625 cm)
Width 5.88 in. (14.7 cm)

Weight 3.2 lb (1.44 kg)

Media 96 and 48 TPI Double Sided High Density Diskettes

Tracks per Inch 96

Number of Tracks 80 (When formatted with MS-DOS)

Data Transfer Rate 300/500 Kb/s

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

360 Kbyte Diskette Drive Specifications

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

Dimensions:

Height 1.60 in. (4.0625 cm)
Depth 8.0 in. (20.625 cm)
Width 5.8 in. (14.7 cm)

Weight 3.2 lb (1.44 kg)

Media 40 TPI Double Sided Double Density Diskettes

Tracks per Inch 48

Number of Tracks 40 (When formatted with MS-DOS)

Data Transfer Rate 250 Kb/s

Power supply specifications:

Input Requirements:

Line 102 to 132 VAC, single phase
Voltage 180 to 264 VAC, single phase
Line Fuse 3 amps 250V fuse for 115 VAC operation,

2.5 amps for 220 VAC operation

Line Frequency 47 to 62 Hz

Cooling Forced air provided by 16 VDC fan
Current 2 amps, maximum at input voltage of 120 VAC,

60 Hz

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

VDC Output: Nominal Current Current Regulation

Voltage Amps Amps Tolerance
VDC Minimum Maximum * Percent

-----------------------------------------------------------------------------­+ 5.0 1.5 15.0 2

- 5.0 0.0 0.5 5
+ 12.25 1.0 5.0 2
+ 12.25 0.0 1.5 3
(internal monitor)

- 12.0 0.0 1.0 5

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

* These values are maximum values based on nominal operating conditions for

temperature, line voltage, line frequency, and altitude.

==============================================================================

Chapter 2. Power On Self Tests (POST)/Problem Isolation

Chapter 2.1 Introduction

This section provides a list of assemblies checked by the Power On Self Test
(POST) and a brief description of the types of error codes. The section also
contains preliminary steps to problem isolation of an error condition and a
problem isolation flowchart for quick reference.

Chapter 2.2 Power On Self Test (POST)

A series of diagnostic tests automatically run on every COMPAQ Personal
Computer system when the system is turned on. These tests are called the
Power On Self Test (POST).

POST checks the following assemblies to ensure that the computer system is
functioning properly:

o Keyboard
o Power Supply
o System Board
o Video Display Controller Board
o Fixed Disk Drive Controller Board
o Diskette/Printer Controller Board
o Asynchronous Communications/Clock Board
o System Board
o Memory

POST also detects the type(s) of mass storage device(s) installed in the
computer.

When the computer is turned on, POST automatically starts and runs. If POST
finds an error in the system, error codes (in the form of beeps) are heard or
error codes (numbers) are visible on the monitor. See Chapter 5, "Error
Messages and Codes," for an explanation of error codes.

Chapter 2.3 Preliminary Steps to Problem Isolation

If you encounter an error condition, complete the following preliminary steps
before starting problem isolation.

1. Place the ON/OFF switch in the OFF position.

2. Disconnect the signal cables of any peripheral devices (printers, modems,

and so on) from the computer.

3. Remove the upper access panel and board slots access cover (see Chapter 7,

"Removal and Replacement Procedures.")

When the upper access panel is removed, the system LED, located on the

system board between the expansion slots, is visible.

4. Remove all non COMPAQ options (board, drives, and so on) from the

computer.

5. Install a loopback plug connector in the parallel port and the

asynchronous port and any other location that requires a loopback plug.

NOTE: If you want to test your printer during the printer test or to log
errors to a printer, reconnect the printer now.

6. Verify that the AC power cable is connected to a usable power outlet.

7. Insert the latest version of the COMPAQ DIAGNOSTICS Program diskette into

drive A and close the drive door.

8. Place the ON/OFF switch in the ON position. See Chapter 4, "DIAGNOSTIC

Procedures," for detailed information on problem isolation.

Chapter 2.4 Problem Isolation Flowchart

The problem isolation flowchart provides a quick reference for identifying and
correcting possible problems that may occur during POST. The flowchart gives
troubleshooting procedures for identifying malfunctions and replacing major
assemblies in the computer and directs you to Chapter 4, "Diagnostic
Procedures," and to Chapter 5, "Error Messages and Codes," for more detailed
troubleshooting information.

Chapter 3. Setup

Please consult the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for current
information on SETUP.

Chapter 4. Diagnostic Procedures

Please consult the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for current
information on DIAGNOSTICS.

Chapter 5. Error Messages and Codes

Chapter 5.1 Introduction

This section provides Power On Self Test error messages, DIAGNOSTIC error
codes, and memory error codes.

The messages and codes are given in tables that list the message or error
code, a description of the error, and the probable failure or required action
to resolve the error condition.

Chapter 5.2 Power On Self Test Error Messages

This section is divided into two tables. The first table contains Power On
Self Test error messages for the COMPAQ PORTABLE 286 Personal Computer. The
second table contains Power On Self Test error messages for the COMPAQ
Portable and COMPAQ PLUS Personal Computers.

An error message results if a problem is encountered during the Power On Self
Test program. This program runs automatically when the system is turned on.

The tables list the messages, the audible (beep) message, and the probable
failure.

Table 5-1. Power On Self Test Error Messages for the COMPAQ PORTABLE 286
Personal Computer
==============================================================================
Message Beeps Probable Failure

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

101 - I/O ROM Error 1 Long, Option ROM

1 Short

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

101 - ROM Error 1 Long, System ROM

1 Short

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

102 - System Board Failure None System Board

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

162 - System Options Error 2 Short SETUP Utility Incorrect

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

163 - Time & Date Not Set 2 Short Invalid time

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

164 - Memory Size Error 2 Short SETUP Utility Incorrect
Discrepancy

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

XX000B YYZZ - 201 Memory None RAM Failure *
Error

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

301 - Keyboard Error None Keyboard

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

302 - System Unit Security 2 Short System Lock
Lock is Locked, Unlock
System Unit Security Lock

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

303 - Keyboard Controller None Keyboard
Error

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

304 - Keyboard or System None Keyboard
Unit Error

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

* See Section 5.4, "Memory Error Codes," for the location of the defective

memory chip.

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

Message Beeps Probable Failure

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

402 - Monochrome Display 1 Long, Monochrome Display Controller Board
Controller Failure 2 Short

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

501 - Display Controller 1 Long, Video Display or Video Controller
Failure 2 Short Board

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

601 - Diskette Controller None Diskette Controller Board
Error

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

1780 - Disk 0 Failure None Fixed Disk Drive

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

1782 - Disk Controller None Fixed Disk Drive
Failure

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

1790 - Disk 0 Error None Fixed Disk Drive Recalibration

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

Parity Check 2 XX000B None Expansion RAM (Main Memory on COMPAQ
YYZZ * PORTABLE 286)

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

Audible 1 Short Power On successful: COMMON (6 MHz)

speed

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

Audible 2 Short Power On successful: FAST (8 MHz)

speed

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

RESUME = "F1" KEY None Any failure

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

* See Section 5.4, "Memory Error Codes," for the location of the defective

memory chip.

==============================================================================

Table 5-2. Power On Self Test Error Messages for the COMPAQ Portable and
COMPAQ PLUS Personal Computers
==============================================================================
Message Beeps Probable Failure

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

Audible 1 Beep Power On successful

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

1XX 1 Long, System ROM or System Board

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

XXYY 20X None Failure

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

3XX or dd 3XX None Keyboard assembly or "stuck" key

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

4XX None Diskette/Printer Board

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

5XX 1 Long, Video Display Unit (VDU) or Video

1 Short

1 Long, Video Display Unit or Video Controller
2 Short Board

2 Short Controller Board

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

6XX None Disk Drive Assembly

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

170X None Fixed Disk Drive Assembly
==============================================================================

Chapter 5.3 Diagnostic Error Codes

DIAGNOSTIC error codes occur if the system recognizes a problem while running
the COMPAQ DIAGNOSTICS Program. These error codes help identify possible
defective subassemblies.

Table 5.3 lists all possible error codes, a description of the error
condition, and the action required to resolve the error condition.

In each case, the required action lists prioritized steps necessary to
correct the problem. After each step is completed, run DIAGNOSTICS to verify
whether the error condition has been corrected. If the error code reappears,
perform the next step, then run the DIAGNOSTICS Program. Follow this
procedure until the DIAGNOSTICS Program no longer detects an error condition.

For assistance in the removal and replacement of a particular subassembly, see
Chapter 7, "Removal and Replacement Procedures."

Table 5-3. DIAGNOSTIC Error Codes
==============================================================================
Error Error Required
Code Description Action

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

Processor
1yy-xx

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

101 - 01 286 CPU test failed Replace the system board.

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

102 - 01 287 Coprocessor initial The following steps apply to error

status word incorrect codes 102 - 01 through 102 - 15:

102 - 02 287 Coprocessor initial 1. Replace the 287 Coprocessor.

control word incorrect 2. Replace the system board.

102 - 03 287 Coprocessor tag word

not all ones

102 - 04 287 Coprocessor tag word

not all zeros

102 - 05 287 Coprocessor exchange

command failed

102 - 06 287 Coprocessor masked

exception incorrectly
handled

102 - 07 287 Coprocessor unmasked

exception codes incorrectly
handled

102 - 08 287 Coprocessor wrong

mask bit set in status
register

102 - 15 287 socket is unoccupied,

or 287 is inoperative

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

Error Error Required
Code Description Action

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

103 - 01 8237 DMA page registers Replace the system board for error

test codes 103 - 01 through 113 - 01.

103 - 02 8237 DMA byte controller

test failed

103 - 03 8237 DMA word controller

test failed

104 - 01 8259 interrupt controller

master test failed

104 - 02 8259 interrupt controller

slave test failed

104 - 03 8259 software RTC is

inoperative

105 - 01 Port bit 6 not at zero

105 - 02 Port bit 5 not at zero

105 - 03 Port bit 3 not at zero

105 - 04 Port bit 1 not at zero

105 - 05 Port bit 0 not at zero

105 - 06 Port bit 5 not at one

105 - 07 Port bit 3 not at one

105 - 08 Port bit 1 not at one

105 - 09 Port bit 0 not at one

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

Error Error Required
Code Description Action

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

Processor
1yy-xx

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

106 - 01 8042 keyboard controller Replace the system board for error

self test failed codes 103 - 01 through 113 - 01.

107 - 01 CMOS RAM test failed

108 - 02 CMOS interrupt test failed

109 - 01 CMOS clock load data test

failed

109 - 02 CMOS clock rollover test

failed

110 - 01 8254 load data test failed

110 - 02 8254 dynamic test failed

111 - 01 Refresh detect test failed

112 - 01 Speed test slow mode out of

range

112 - 02 Speed test mixed mode out

of range

112 - 03 Speed test fast mode out of

range

112 - 04 Speed test unable to enter

slow mode

112 - 05 Speed test unable to enter

mixed mode

112 - 06 Speed test unable to enter

fast mode

112 - 07 Speed test system error

113 - 01 Protected mode test failed

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

114 - 01 Speaker test failed 1. Replace the speaker.

2. Replace the system board.

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

Error Error Required
Code Description Action

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

Memory *
2yy-xx

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

201 - 01 Memory machine ID test The following steps apply to error

codes 201 - 01 through 202 - 01:

201 - 02 Memory machine type test (Error during saving test program

failed memory):

201 - 03 Memory machine ID & type 1. Replace VDU controller board.

tests failed 2. Replace the system ROM.

3. Replace the system board.

202 - 01 Memory system ROM checksum

failed

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

203 - 01 Memory write/read test The following steps apply to error

failed codes 203 - 01 through 205 - 03:

203 - 02 Error during saving program 1. Replace the defective memory

memory in write/read test chip if an error code is

accompanied by an XX000B YYZZ

203 - 03 Error during restore of code.

program in write/read test 2. Replace the system board.

204 - 01 Memory address test failed

204 - 02 Error during saving program

memory in address test

204 - 03 Error during restore of

program memory address test

205 - 01 Walking I/O test failed

205 - 02 Error during saving program

memory in walking I/O test

205 - 03 Error during restore of

program memory in walking
I/O test

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

* See Section 5.4, "Memory Error Codes."

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

Error Error Required
Code Description Action

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

Keyboard
3yy-xx

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

301 - 01 Keyboard short test, 8042 The following steps apply to error

self test failed codes 301 - 01 through 304 - 01:

301 - 02 Keyboard short test, 1. Replace the keyboard.

interface test failed 2. Replace the system board.

301 - 03 Keyboard short test, echo

test failed

301 - 04 Keyboard short test,

keyboard reset failed

302 - 01 Keyboard long test failed

303 - 01 Keyboard LED test, 8042

self test failed

303 - 02 Keyboard LED test, reset

test failed

303 - 03 Keyboard LED test, reset

test failed

303 - 04 Keyboard LED test, LED

command test failed

303 - 05 Keyboard LED test, LED

command test failed

303 - 06 Keyboard LED test, LED

command test failed

303 - 07 Keyboard LED test, LED

command test failed

303 - 08 Keyboard LED test, command

byte restore test failed

303 - 09 Keyboard LED test, LEDs

failed to light

304 - 01 Keyboard typomatic test

failed

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

315 - 01 Security lock is 1. Replace the security lock.

inoperative

315 - 02 Security lock sticks in

locked position

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

Error Error Required
Code Description Action

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

Printer
4yy-xx

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

401 - 01 Printer failed or not The following steps apply to error

connected codes 401 - 01 through 403 - 01:

402 - 01 Printer data register 1. If a printer is connected, be

failed sure it is turned ON and in

the online mode.

402 - 02 Printer controller register 2. Check switch 2 on the

failed diskette/tape controller board

(see Chapter 8). *

402 - 03 Printer data and controller 3. Replace the printer and/or the

register failed printer controller cable.

4. Replace the diskette/tape

402 - 04 Printer loopback failed controller board. *

5. Replace the system board.

402 - 05 Printer loopback and data

register failed * 286 based COMPAQ Personal

Computers only

402 - 06 Printer loopback and

controller register failed

402 - 07 Printer loopback, data,

and controller register
failed

402 - 08 Printer interrupt test

failed

402 - 09 Printer interrupt and data

failed

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

Error Error Required
Code Description Action

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

402 - 10 Printer interrupt and The following steps apply to error

controller register failed codes 401 - 01 through 403 - 01:

402 - 11 Printer interrupt data, and 1. If a printer is connected, be

controller register failed sure it is turned ON and in

the online mode.

402 - 12 Printer interrupt and 2. Check switch 2 on the

loopback failed diskette/tape controller board

(see Chapter 8). *

402 - 13 Printer interrupt, loopback, 3. Replace the printer and/or the

and data register failed printer controller cable.

4. Replace the diskette/tape

402 - 14 Printer interrupt, loopback, controller board. *

and controller register 5. Replace the system board.
failed

* 286 based COMPAQ Personal

402 - 15 Printer interrupt, Computers only

loopback, data, and
controller register failed

402 - 16 Printer unexpected

interrupt received

403 - 01 Printer pattern test failed

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

Error Error Required
Code Description Action

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

Video Display Unit (VDU)
5yy-xx

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

501 - 01 VDU controller test failed The following steps apply to error

codes 501 - 01 through 512 - 01:

502 - 01 VDU memory test failed

1. Replace the VDU controller

503 - 01 VDU attribute test failed board.

2. Replace the VDU signal cable.

504 - 01 VDU character set test 3. Replace VDU subassembly.

failed 4. Replace the system board.

505-01 VDU9x14character cell

test

506-01 VDU80x25mode8x8

character cell test
failed

507 - 01 VDU 40 x 25 mode test

failed

508 - 01 VDU 320 x 200 mode color

set 0 test failed

509 - 01 VDU 320 x 200 mode color

set 1 test failed

510 - 01 VDU 640 x 200 mode test

failed

511 - 01 VDU screen memory page test

failed

512 - 01 VDU gray scale test failed

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

Error Error Required
Code Description Action

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

516 - 01 Lightpen text mode test The following steps apply to error

failed - no response codes 516 - 01 through 516 - 04:

516 - 0 Lightpen text mode test 1. Replace the lightpen.

failed - invalid response 2. Replace the VDU controller

board.

516 - 03 Lightpen medium resolution

mode test failed - no
response

516 - 04 Lightpen medium resolution

mode test - invalid response

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

Diskette Drive
6yy-xx

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

600 - xx Diskette drive ID The following steps apply to all

6yy - xx related error codes.

601 - xx Diskette drive format

1. Check shunt jumper J2 setting

602 - xx Diskette drive read on the diskette/tape

controller board (see

603 - xx Diskette drive write/read/ Chapter 8). *

compare 2. Replace the diskette/tape

controller board. *

604 - xx Diskette drive random seek 3. Replace the diskette drive

drive power and signal cables.

4. Replace the diskette drive

605 - xx Diskette drive ID media assembly.

test 5. Replace the system board.

606 - xx Diskette drive speed test * 286 based COMPAQ Personal

Computers only

607 - xx Diskette drive wrap test

608 - xx Diskette drive write

protect test

609 - xx Diskette drive reset

controller test

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

Error Error Required
Code Description Action

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

Diskette Drive
6yy-xx

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

610 - xx Diskette drive change line The following steps apply to all

test 6yy - xx related error codes.

610 - 01 Exceeded maximum soft error 1. Check shunt jumper J2 setting

limit on the diskette/tape

controller board (see

610 - 02 Exceeded maximum hard error Chapter 8). *

limit 2. Replace the diskette/tape

controller board. *

610 - 03 Previously exceeded max 3. Replace the diskette drive

soft error limit power and signal cables.

4. Replace the diskette drive

610 - 04 Previously exceeded max assembly.

hard error limit 5. Replace the system board.

610 - 05 Failed to reset controller * 286 based COMPAQ Personal

Computers only

610 - 06 Fatal error while reading

610 - 07 Fatal error while writing

610 - 08 Failed compare of write/

read/compare

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

Error Error Required
Code Description Action

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

Diskette Drive
6yy-xx

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

6xx - 09 Failed to format a track The following steps apply to all

6yy - xx related error codes.

610 - 10 Failed sector wrap test

1. Check shunt jumper J2 setting

610 - 20 Failed to get drive type on the diskette/tape

controller board (see

610 - 21 ** Failed to get change line Chapter 8). *

status 2. Replace the diskette/tape

controller board. *

610 - 22 Failed to clear change 3. Replace the diskette drive

power and signal cables.

610 - 23 Failed to set drive type in 4. Replace the diskette drive

ID media assembly.

5. Replace the system board.

610 - 24 Failed to read media

* 286 based COMPAQ Personal

610 - 25 Failed to verify media Computers only

610 - 26 Failed to read media in ** The following applies to

speed test 286 based computers:

610 - 27 Failed speed limits For a 1.2 megabyte diskette

610 - 28 Failed write protect test drive. For a 360 Kbyte

610 - 29 Failed to read media in modification has not been

file write test performed. See Service

610 - 40 Cylinder 0 Error

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

Error Error Required
Code Description Action

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

Serial
11yy - xx

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

1101 - 01 Serial Port Test, UART The following steps apply to all

DLAB bit failure 11yy - xx related error codes:

drive, replace the diskette

diskette drive, a drive

Bulletin 25.

1101 - 02 Serial Port Test, Line 1. Check diskette/tape controller

input or UART fault board for proper shunt jumper

settings (see Chapter 8). *

1101 - 03 Serial Port Test, Address 2. Replace the diskette/tape

line fault controller board.

3. Replace the system board.

1101 - 04 Serial Port Test, Data line

fault * 286 based COMPAQ Personal

Computers only

1101 - 05 Serial Port Test, UART

control signal

1101 - 06 Serial Port Test, ART THRE

bit failure

1101 - 07 Serial Port Test, UART DATA

READY bit failure

1101 - 08 Serial Port Test, UART

TX/RX buffer failure

1101 - 09 Serial Port Test, INTERRUPT

circuit failure

1101 - 10 Serial Port Test, COM 1 set

to interrupt 3

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

Error Error Required
Code Description Action

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

Serial
11yy - xx

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

1101 - 11 Serial Port Test, COM 2 The following steps apply to all

set to interrupt 4 11yy - xx related error codes:

1101 - 12 Serial Port Test, 1. Check diskette/tape controller

DRIVER/RECEIVER control board for proper shunt jumper
signal failure settings (see Chapter 8). *

2. Replace the diskette/tape

1101 - 13 Serial Port Test, UART controller board.

control signal interrupt 3. Replace the system board.
failure

* 286 based COMPAQ Personal

1101 - 14 Serial Port Test, Computers only

DRIVER/RECEIVER data failure

1109 - 01 Serial Clock Test, register

initialization failure

1109 - 02 Serial Clock Test, register

rollover failure

1109 - 03 Serial Clock Test, clock

reset failure

1109 - 04 Serial Clock Test, input

line or clock failure

1109 - 05 Serial Clock Test, address

line failure

1109 - 06 Serial Clock Test, data

line failure

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

Error Error Required
Code Description Action

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

Fixed Disk Drive
17yy - xx

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

1700 - xx Fixed disk drive ID drive The following steps apply to error

test type codes 1700 - xx through 1716 - 59:

1701 - xx Fixed disk drive format 1. Check the fixed disk drive

test controller board for the

proper switch setting

1702 - xx Fixed disk drive read test (see Chapter 8). *

2. Replace the fixed disk drive

1703 - xx Fixed disk drive write/ signal and power cables.

read/compare test 3. Replace the fixed disk drive

controller board. *

1704 - xx Fixed disk drive random 4. Replace the fixed disk drive

seek test assembly.

5. Replace the system board.

1705 - xx Fixed disk drive controller

test * 286 based COMPAQ Personal

Computers only

1706 - xx Fixed disk drive ready test

1707 - xx Fixed disk drive

recalibrate test

1708 - xx Fixed disk drive format bad

track test

1709 - xx Fixed disk drive reset

controller test

1710 - xx Fixed disk drive park head

test

1714 - xx Fixed disk drive file write

test

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

Error Error Required
Code Description Action

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

Fixed Disk Drive
17yy - xx

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

1715 - xx Fixed disk drive head select The following steps apply to error

test codes 1700 - xx through 1716 - 59:

1716 - xx Fixed disk drive conditional 1. Check the fixed disk drive

format test controller board for the

proper switch setting

1716 - 01 Exceeded maximum soft error (see Chapter 8). *

limit 2. Replace the fixed disk drive

signal and power cables.

1716 - 02 Exceeded maximum hard error 3. Replace the fixed disk drive

limit controller board. *

4. Replace the fixed disk drive

1716 - 03 Previously exceeded maximum assembly.

soft error limit 5. Replace the system board.

1716 - 04 Previously exceeded maximum * 286 based COMPAQ Personal

hard error limit Computers only

1716 - 05 Failed to reset controller

1716 - 06 Fatal error while reading

1716 - 07 Fatal error while writing

1716 - 08 Failed compare of write/

read/compare test

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

Error Error Required
Code Description Action

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

Fixed Disk Drive
17yy - xx

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

1716 - 09 Failed to format a track The following steps apply to error

codes 1700 - xx through 1716 - 59:

1716 - 10 Failed sector wrap test

1. Check the fixed disk drive

1716 - 40 Failed cylinder 0 controller board for the

proper switch setting

1716 - 41 Drive not ready (see Chapter 8). *

2. Replace the fixed disk drive

1716 - 42 Recalibrate failed fixed signal and power cables.

disk drive 3. Replace the fixed disk drive

controller board. *

1716 - 43 Failed to format bad track 4. Replace the fixed disk drive

assembly.

1716 - 44 Failed fixed disk drive 5. Replace the system board.

controller diagnostics

* 286 based COMPAQ Personal

1716 - 45 Failed to get drive Computers only

parameters from ROM

1716 - 46 Invalid drive parameters

found in ROM

1716 - 47 Failed to park heads

1716 - 48 Failed to move disk table to

RAM

1716 - 50 Failed file I/O test in

write test

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

Error Error Required
Code Description Action

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

Fixed Disk Drive
17yy - xx

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

1716 - 51 Failed file I/O test The following steps apply to error

in read test codes 1700 - xx through 1716 - 59:

1716 - 52 Failed file I/O test in 1. Check the fixed disk drive

compare test controller board for the

proper switch setting

1716 - 53 Failed drive/head register (see Chapter 8). *

test 2. Replace the fixed disk drive

signal and power cables.

1716 - 54 Failed digital input 3. Replace the fixed disk drive

register test controller board. *

4. Replace the fixed disk drive

1716 - 55 Cylinder 1 failed assembly.

5. Replace the system board.

1716 - 56 Controller RAM failed

* 286 based COMPAQ Personal

1716 - 57 Controller to drive test Computers only

failed

1716 - 58 Failed to write sector

buffer

1716 - 59 Failed to read sector

buffer

1716 - 60 Non COMPAQ fixed disk

drive controller ROM

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

Error Error Required
Code Description Action

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

Tape Drive
19yy - xx

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

1901 - xx * Tape servo write The following steps apply to all

19yy - xx error codes:

1902 - xx * Tape format

1. Replace the tape cartridge.

1903 - xx * Tape drive sensor test 2. Replace the signal cable.

3. Replace the diskette/tape

1904 - xx * Tape BOT/EOT test controller board.

4. Replace the tape drive

1905 - xx * Tape read test assembly.

1906 - xx * Tape write/read/compare * 286 based COMPAQ Personal

test Computers only

1906 - 01 Drive not installed

1906 - 02 Cartridge not installed

1906 - 03 Tape motion error

1906 - 04 Drive busy error

1906 - 05 Track seek error

1906 - 06 Tape write protected error

1906 - 07 Tape already servo written

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

Error Error Required
Code Description Action

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

Tape Drive
19yy - xx

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

1906 - 08 Unable to servo write The following steps apply to all

19yy - xx error codes:

1906 - 09 Unable to format

1. Replace the tape cartridge.

1906 - 10 Format mode error 2. Replace the signal cable.

3. Replace the diskette/tape

1906 - 11 Drive recalibration error controller board.

4. Replace the tape drive

1906 - 12 Tape not servo written assembly.

1906 - 13 Tape not formatted * 286 based COMPAQ Personal

Computers only

1906 - 14 Drive timeout error

1906 - 15 Sensor error flag

1906 - 16 Block locate (block ID)

error

1906 - 17 Soft error limit exceeded

1906 - 18 Fixed error limit exceeded

1906 - 19 Write error (probably ID

error)

1906 - 20 NEC765 fatal error

1906 - 21 Got servo pulses 2nd time

but not 1st

1906 - 22 Never got to EOT after

servo check

==============================================================================

Chapter 5.4 Memory Error Codes

This section is divided into two parts. The first part contains memory error
codes for the COMPAQ PORTABLE 286 Personal Computer. The second part contains
memory error codes for the COMPAQ Portable and COMPAQ PLUS Personal Computers.

Memory error codes result when the system detects a memory fault during the
Power On Self Test or as a result of a diagnostic test. The test programs
attempt to isolate the memory fault to a specific chip, then generate a
memory error code that specifies which memory chip to replace. In some
cases, replacing the memory chip will not solve the problem because: 1) the
system may be unable to accurately determine which chip or chips are at
fault, or 2) the problem may be due to a failure in the memory support
circuitry, not the memory device.

The memory error code points to a specific memory address. The physical
location of the memory address depends on the type of system, the number and
type of memory boards installed, and the type of memory device used (64 Kbyte
RAMs or 256 Kbyte RAMs).

COMPAQ PORTABLE 286 Memory Error Codes

Memory error codes are in the XX000B YYZZ format.

o XX equals the 128 Kbyte memory segment (bank) in which an error is

detected.

o 000 is always equal to 000 (not used)

o B identifies whether the defective memory chip is in the high byte or the

low byte of the memory bank.

o WhenB=0,YYdefines the defective chip row location within the low byte

of the memory bank.

o WhenB=1,ZZdefines the defective chip row location within the high byte

of the memory bank.

For example, assume error code 020001 0010 appears on the monitor. First
determine which table to reference (see COMPAQ PORTABLE 286 Memory
Configuration). Next, determine which bank to reference and which byte, high
or low. Finally, determine the defective chip row location. In this example,
error code 020001 0010 specifies chip U50 in Table 5.4-1. Use the following
charts to locate a defective memory chip:

COMPAQ PORTABLE 286 Memory Configuration
==============================================================================
RAM Type Error Code Memory See

xx Value Device Location Table

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

64 Kbyte 00 to 02 (0 - 256 Kbytes) System Board 5.4-1

256 Kbyte 00 to 08 (0 - 640 Kbytes) System Board 5.4-2

64 Kbyte or
256 Kbyte 10 to 2E (1 - 3 megabytes) Memory Expansion Board 5.4-3

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

NOTE: xx codes 0A to 0F represent the memory space for the video memory and
system ROMs. Errors in the video memory or system ROM space are not reported
in the XX000B YYZZ error message format.
==============================================================================

Table 5.4-1. Defective Memory Chip Isolation Map for the COMPAQ PORTABLE 286
System Board Using 64 Kbyte RAMs (0 - 256 Kbytes)
==============================================================================

XX=00 XX=02
Bank 0 Bank 1

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

Data Bit B = 0 B = 1 B = 0 B = 1
YY or ZZ Low High Low High

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

01 U5 U6 U7 U8

02 U20 U21 U22 U23

04 U25 U26 U27 U28

08 U41 U42 U43 U44

10 U47 U48 U49 U50

20 U63 U64 U65 U66

40 U70 U71 U72 U73

80 U81 U82 U83 U84

00 U88 U89 U90 U91
==============================================================================

Table 5.4-2. Defective Memory Chip Isolation Map for the COMPAQ PORTABLE 286
System Board Using 256 Kbyte RAMs (0 - 640 Kbytes)
==============================================================================

XX=02
XX = 00 06, 08
Bank 0 Bank 1

-----------------------------------------------------------------------------­Data Bit B = 0 B = 1 B = 0 B = 1
YY or ZZ Low High Low High

-----------------------------------------------------------------------------­01 U5 U6 U7 U8

02 U20 U21 U22 U23

04 U25 U26 U27 U28

08 U41 U42 U43 U44

10 U47 U48 U49 U50

20 U63 U64 U65 U66

40 U70 U71 U72 U73

80 U81 U82 U83 U84

00 U88 U89 U90 U91
==============================================================================

Table 5.4-3. Defective Memory Chip Isolation Map for a Memory Expansion Board
Mapped into the 1 - 3 Megabyte Memory Space (256 Kbyte RAMs)
==============================================================================

XX = 10, 12, XX = 18, 1A, XX = 20, 22, XX = 28, 2A,
14, 16 1C, 1E 24, 26 2C, 2E
Bank 1 Bank 2 Bank 3 Bank 4

-----------------------------------------------------------------------------­Data Bit B = 1 B = 0 B = 1 B = 0 B = 1 B = 0 B = 1 B = 0
YY or ZZ High Low High Low High Low High Low

-----------------------------------------------------------------------------­80 U3 U12 U21 U30 U39 U48 U57 U66

40 U4 U13 U22 U31 U40 U49 U58 U67

20 U5 U14 U23 U32 U41 U50 U59 U68

10 U6 U15 U24 U33 U42 U51 U60 U69

08 U7 U16 U25 U34 U43 U52 U61 U70

04 U8 U17 U26 U35 U44 U53 U62 U71

02 U9 U18 U27 U36 U45 U54 U63 U72

01 U10 U19 U28 U37 U46 U55 U64 U73

00 U11 U20 U29 U38 U47 U56 U65 U74
==============================================================================

COMPAQ Portable and COMPAQ PLUS Memory Error Codes

Memory error codes for the COMPAQ Portable and COMPAQ PLUS Personal Computers
will appear in an "XXYY 201" format.

XX - Denotes the beginning address of the error code (or the bank in which the

error occurred)

YY - Denotes the failed bit

Once all corrections have been completed and all boards have been reinstalled
in the system, begin the problem isolation procedure again to verify proper
operation of the CPU/memory subsystem.

Table 5.4-4. COMPAQ Portable and COMPAQ PLUS System Board Memory
==============================================================================
Error Failure Location of
Code Description Failed Chip Required Action

-----------------------------------------------------------------------------­(XXYY 201)

-----------------------------------------------------------------------------­0000 201 Bank 0, Parity U39 Replace System Board

0001 201 Bank 0, Data Bit 0 U97 or U53 * Replace System Board

0002 201 Bank 0, Data Bit 1 U87 or U53 * Replace System Board

0004 201 Bank 0, Data Bit 2 U80 or U53 * Replace System Board

0008 201 Bank 0, Data Bit 3 U74 or U53 * Replace System Board

0010 201 Bank 0, Data Bit 4 U70 or U45 * Replace System Board

0020 201 Bank 0, Data Bit 5 U63 or U45 * Replace System Board

0040 201 Bank 0, Data Bit 6 U54 or U45 * Replace System Board

0080 201 Bank 0, Data Bit 7 U46 or U45 * Replace System Board

1000 201 Bank 1, Parity Bit U38 Replace System Board

1001 201 Bank 1, Data Bit 0 U96 or U69 * Replace System Board

1002 201 Bank 1, Data Bit 1 U86 or U69 * Replace System Board

1004 201 Bank 1, Data Bit 2 U79 or U69 * Replace System Board

1008 201 Bank 1, Data Bit 3 U73 or U69 * Replace System Board

-----------------------------------------------------------------------------­* Location of Failed Chip if using Alternate Bank 2 and 3.

-----------------------------------------------------------------------------­Error Failure Location of
Code Description Failed Chip Required Action

-----------------------------------------------------------------------------­(XXYY 201)

-----------------------------------------------------------------------------­1010 201 Bank 1, Data Bit 4 U69 or U62 * Replace System Board

1020 201 Bank 1, Data Bit 5 U62 or U62 * Replace System Board

1040 201 Bank 1,Data Bit 6 U53 or U62 * Replace System Board

1080 201 Bank 1, Data Bit 7 U45 or U62 * Replace System Board

2000 201 Bank 2, Parity Bit U37 or U37 * Replace Memory Chip

2001 201 Bank 2, Data Bit 0 U95 or U79 * Replace Memory Chip

2002 201 Bank 2, Data Bit 1 U85 or U79 * Replace Memory Chip

2004 201 Bank 2, Data Bit 2 U78 or U79 * Replace Memory Chip

2008 201 Bank 2, Data Bit 3 U72 or U79 * Replace Memory Chip

2010 201 Bank 2, Data Bit 4 U68 or U73 * Replace Memory Chip

2020 201 Bank 2, Data Bit 5 U61 or U73 * Replace Memory Chip

2040 201 Bank 2, Data Bit 6 U52 or U73 * Replace Memory Chip

2080 201 Bank 2, Data Bit 7 U44 or U73 * Replace Memory Chip

3000 201 Bank 3, Parity Bit U36 or U36 * Replace Memory Chip

3001 201 Bank 3, Data Bit 0 U94 or U96 * Replace Memory Chip

3002 201 Bank 3, Data Bit 1 U84 or U96 * Replace Memory Chip

3004 201 Bank 3, Data Bit 2 U77 or U96 * Replace Memory Chip

3008 201 Bank 3, Data Bit 3 U71 or U96 * Replace Memory Chip

3010 201 Bank 3, Data Bit 4 U67 or U86 * Replace Memory Chip

3020 201 Bank 3, Data Bit 5 U60 or U86 * Replace Memory Chip

3040 201 Bank 3, Data Bit 6 U51 or U86 * Replace Memory Chip

3080 201 Bank 3, Data Bit 7 U43 or U86 * Replace Memory Chip

-----------------------------------------------------------------------------­* Location of Failed Chip if using Alternate Bank 2 and 3.
==============================================================================

Table 5.4-5. COMPAQ Portable and COMPAQ PLUS Extended Memory Codes
==============================================================================
xx Code Beginning Address

-----------------------------------------------------------------------------­40yy 201 256 Kbytes

48yy 201 288 Kbytes

50yy 201 320 Kbytes

58yy 201 352 Kbytes

60yy 201 384 Kbytes

68yy 201 416 Kbytes

70yy 201 448 Kbytes

78yy 201 480 Kbytes

80yy 201 512 Kbytes

-----------------------------------------------------------------------------­yy Code Failed Bit

-----------------------------------------------------------------------------­xx00 Parity Bit

xx01 Data Bit 0

xx02 Data Bit 1

xx04 Data Bit 2

xx08 Data Bit 3

xx10 Data Bit 4

xx20 Data Bit 5

xx40 Data Bit 6

xx80 Data Bit 7
==============================================================================

Chapter 6. Illustrated Parts Catalog

Chapter 6.1 Illustrated Parts List for Compaq Portable and Compaq Plus Personal Computers

Section 6.1 provides a reference for specific COMPAQ Portable and COMPAQ PLUS
Computer part (or parts kit) numbers used to place parts orders with Compaq
Computer Corporation.

Each parts list has three columns, which are:

o ITEM NUMBER - A reference number for parts in the list.

o PART NUMBER - The number to use when ordering parts from COMPAQ Computer

Corporation.

o DESCRIPTION - The name of the particular part or parts kit.

This section is arranged so that every parts list is preceded by its related
illustrated parts breakdown.

NOTE: If you request a RUSH shipment, your order is processed and shipped
within 24 hours.

Table 6.1-1. COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: System (Front)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 101709-001 Enclosed Chassis Assembly

2 100374-001 ** AC Power Cord

3 100487-001 ** Keyboard Assembly

--------------------------------------------------------------------------­** Part number no longer available.
==============================================================================

Table 6.1-2. COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: Chassis (Front)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 100025-001 ** Handle

2 100025-001 ** Handle Bushing

3 100025-001 ** Handle End Cap

4 101097-001 ** Upper Case

5 101098-001 ** Access Panel

6 100025-001 ** Screw, 10-32 x 3/8

T-15 Torx:

7 101750-001 ** Chassis Assembly

8 102709-001 * Brightness knob

9 101099-001 ** Front Bezel

10 101097-001 ** Lower Case

11 100077-001 ** VDU Foot/Detent

12 100031-001 ** Sliding Door Panel

-----------------------------------------------------------------------------­* This part is included in the Miscellaneous Hardware Kit (PN 102709-001).

** Part number no longer available.
==============================================================================

Table 6.1-3. COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: Common Chassis (Front)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 105034-001 ** Monitor Assembly

2 102709-001 * Screw, 4-40 1/4 T-10 Torx

3 100436-002 ** High Voltage Access Plate

4 100330-001 ** Storage Device Access Plate

5 100438-001 ** Board Slots Access Plate

6 102709-001 * Printed Circuit Board

Retainer

7 101340-001 ** VDU Controller Board

8 100644-001 ** Fixed Disk Drive Controller

Board

9 100512-001 *** ** Fixed Disk Drive Controller

Cables

10 100512-001 *** ** Diskette Drive Controller

Cable

11 101341-001 ** Diskette/Printer Controller

Board

12 101750-001 ** Chassis Assembly

13 100643-001 ** 10 Megabyte Fixed Disk Drive

14 100437-001 ** Blank Drive Plate

15 101421-001 ** 360 Kbyte Diskette Drive

16 101031-001 ** Diskette Drive Shield

(Half Height)

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

* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001).
*** These parts are included in the Cable Kit (PN 100512-001 **).
** Part number no longer available.
==============================================================================

Table 6.1-4. COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: Mechanical Chassis (Front)
==============================================================================
Item Number Part Number Description

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

1 102709-001 * Printed Circuit Board

2 100475-001 ** Power Supply Assembly

3a *** 102845-001 ** Fan/Bracket Assembly

Standoff

3b  100482-001 ** Fan/Bracket Assembly

4 102709-001 * Drive Ground Strap

5 102709-001 * Drive Shock Mount

6 100478-001 ** System Board Assembly

7 100478-001 ** System Board Support Bracket

8 102709-001 * Screw, 8-32 x 3/8 T-15 Torx

9 101798-001 ** Power Switch Filter Assembly

10 102930-001 AC Line Fuse

11 102709-001 * Screw, 4-40 x 1/4 T-10 Torx

12 100439-001 ** System Board Connector

Access Plate

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

* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001).
** Part number no longer available.
*** For portable computers with serial number 1524020B0001 or above.
 For portable computers with serial numbers below 1524020B0001.
==============================================================================

Table 6.1-5. COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: Monitor Enclosure (Front)
==============================================================================
Item Number Part Number Description

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

1 105034-001 ** Monitor Assembly

2 100512-001 * ** VDU Signal Cable

3 100493-001 ** Speaker Assembly

4 100442-002 ** Monitor Floor

-----------------------------------------------------------------------------­* This part is contained in the Cable Kit (PN 100512-001 **).

** Part number no longer available.
==============================================================================

Table 6.1-6: COMPAQ Portable and COMPAQ PLUS Personal Computers Parts
List: System Chassis (Front)
==============================================================================
Item Number Part Number Description

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

1 100260-001 Power Cable Harness Assembly

2 102709-001 * Screw, 4-40 x 1/4 T-10 Torx

3 102709-001 * Screw, 6-32 x 1/4 T-14 Torx

4 100429-001 ** Blank, I/O Mounting Bracket

5 102709-001 * Washer, Internal Tooth

6 102709-001 * 4-40 Hex Nut

7 102709-001 * Brightness Potentiometer

8 102709-001 * Drive Shock Mount

9 101750-001 ** System Chassis Assembly

10 102709-001 * Ty-Wrap

11 102709-001 * Push Mount

-----------------------------------------------------------------------------­* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001).

** Part number no longer available.
==============================================================================

Chapter 6.2 Illustrated Parts List for Compaq Portable 286 Personal Computer

Section 6.2 provides a reference for specific COMPAQ PORTABLE 286 Personal
Computer part (or parts kit) numbers used to place part orders with Compaq
Computer Corporation.

Each parts list has three columns, which are:

o ITEM NUMBER - A reference number for parts in the list.

o PART NUMBER - The number to use when ordering parts from Compaq Computer

Corporation.

o DESCRIPTION - The name of the particular part or parts kit.

This section is arranged so that every parts list is preceded by its related
illustrated parts breakdown.

Table 6.2-1. COMPAQ PORTABLE 286 Personal Computer Parts List:
System (Front)
==============================================================================

Item Number Part Number Description

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

1 101710-001 Assembly, Enclosed Chassis

2 100374-001 ** AC Line Power Cord

3 101790-001 ** Keyboard Assembly

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

** Part number no longer available.
==============================================================================

Table 6.2-2. COMPAQ PORTABLE 286 Personal Computer Parts List:
Chassis (Front)
==============================================================================
Item Number Part Number Description

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

1 100025-001 ** Handle

2 100025-001 ** Handle Bushing

3 100025-001 ** Handle End Cap

4 101097-001 ** Upper Case

5 101098-001 ** Access Panel

6 100025-001 ** Screw, 10-32 x 3/8 T-15 Torx

7 101750-001 ** Chassis Assembly

8 102709-001 * Brightness Knob

9 101763-001 ** Front Bezel

10 101097-001 ** Lower Case

11 102709-001 * VDU Foot/Detent

12 100031-001 ** Sliding Door Panel

-----------------------------------------------------------------------------­* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001).

** Part number no longer available.
==============================================================================

Table 6.2-3. COMPAQ PORTABLE 286 Personal Computer Parts List:
Common Chassis (Front) - A
==============================================================================
Item Number Part Number Description

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

1 105034-001 ** Monitor Assembly

2 102709-001 * Screw, 4-40 1/4 T-10 Torx

3 100436-002 ** High Voltage Access Plate

4 101747-001 ** Storage Drive Access Plate

5 101029-003 ** Board Slots Access Plate

6 102709-001 * PC Board Retainer

7 101340-001 ** VDU Controller Board

8 102933-001 *** ** Diskette/Tape Controller

Cable

9 102705-001 ** Diskette/Tape Controller

Board

10 102933-001 *** ** Fixed Disk Drive

Controller Cables

11 105033-001 ** Memory Expansion Board

12 102933-001 *** ** Mass Storage Power Cable

13 101750-001 ** Chassis Assembly

14 102778-001 Fixed Disk Drive Controller

Board

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

* These parts are all included in the Miscellaneous Hardware Kit

(PN 102709-001).
*** These parts are all included in the Cable Kit (PN 102933-001 **).
** Part number no longer available.
==============================================================================

Table 6.2-4. COMPAQ PORTABLE 286 Personal Computer Parts List:
Common Chassis (Front) - B
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 101750-001 ** Chassis Assembly

2 102709-001 * Fixed Disk Drive LED

3 105032-001 ** Security Lock Assembly

4 101767-001 ** Security Lock Bezel

5 105032-001 ** Security Lock Clip

6 101732-001 ** Blank Drive Plate

7 102706-001 ** 20 Megabyte Fixed Disk Drive

8 102709-001 * Dual Drive Insulator

9 102775-001 1.2 Megabyte Diskette Drive

10 102928-001 360 Kbyte Diskette Drive

11 102779-001 ** 10 Megabyte Tape Drive

12 101299-001 ** Dual Drive Enclosure

13 101488-001 ** Tape Drive Cartridge

14 102709-001 * Security Lock Switch

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

* These parts are all included in the Miscellaneous Hardware Kit

(PN 102709-001).

** Part number no longer available.
==============================================================================

Table 6.2-5. COMPAQ PORTABLE 286 Personal Computer Parts List:
Mechanical Chassis (Rear)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 102709-001 * Printed Circuit Board Standoff

2 102818-001 ** Power Supply Board Assembly

3 101796-001 ** Fan/Bracket Assembly

4 102709-001 * Drive Ground Strap

5 102709-001 * Drive Shock Mount

6 101795-001 ** System Board Assembly

7 101795-001 ** System Board Support Bracket

8 102709-001 * Screw, 4-40 1/4 T-10 Torx

9 102709-001 * Screw, 8-32 x 3/8 T-15 Torx

10 101798-001 ** Power Switch Filter Assembly

11 102930-001 AC Line Fuse

12 100439-001 ** System Board Connector

Access Plate

13 102929-001 (replaced by

160272-001) Lithium Battery

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

* These parts are all included in the Miscellaneous Hardware Kit

(PN 102709-001).

** Part number no longer available.
==============================================================================

Table 6.2-6. COMPAQ PORTABLE 286 Personal Computer Parts List:
Monitor Enclosure (Front)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 105034-001 ** Monitor Assembly

2 102933-001 * ** VDU Signal Cable

3 100493-001 ** Speaker Assembly

4 100442-002 ** Monitor Floor

5 102933-001 * ** Monitor Power Cable

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

* These parts are all included in the Cable Kit (PN 102933-001 **).

** Part number no longer available.
==============================================================================

Table 6.2-7. COMPAQ PORTABLE 286 Personal Computer Parts List:
System Chassis (Front)
==============================================================================
Item Number Part Number Description

-----------------------------------------------------------------------------­1 102933-001 *** ** System Power Cable

2 102709-001 * Screw, 6-32 x 1/4 T-15 Torx

3 100429-001 ** Blank I/O Mounting Bracket

4 102709-001 * Screw, 4-40 x 1/4 T-10 Torx

5 102709-001 * Washer, Internal Tooth

6 102709-001 * 4-40 Hex Nut

7 102709-001 * Brightness Potentiometer

8 102709-001 * Drive Shock Mount

9 101750-001 ** System Chassis Assembly

10 102709-001 * Tie Wrap

11 102709-001 * Push Mount

-----------------------------------------------------------------------------­* These parts are all included in the Miscellaneous Hardware Kit

(PN 102709-001).
*** This part is included in the Cable Kit (PN 102933-001 **).
** Part number no longer available.
==============================================================================

Chapter 7. Removal and Replacement Procedures

Chapter 7.1 Introduction

Before starting removal procedures, review Chapter 6, "Illustrated Parts
Catalog," to become familiar with the various part names and locations.

Removal and replacement procedures in this section are written generically for
all COMPAQ Portable Computers, except in cases where procedures differ
because of design differences. These differences affect the removal and
replacement procedures for the power supply subsystem and the monitor
enclosure. When procedures differ, specific instructions are given.

Also note that when you are instructed to cut a tie wrap for removal of an
assembly, you should also replace the tie wrap for reassembly.

NOTE: Run the latest version of COMPAQ DIAGNOSTICS to verify the proper
operation of the replaced component.

Chapter 7.2 Preparation Procedure

Before beginning the procedures in this section, complete the following steps:

1. Place the ON/OFF switch (on the side of the computer) in the OFF position.

2. Close the keyboard and secure it in place by sliding the latches to the

LOCK position. Fold the keyboard feet in place. (Figure 7.2-1).

3. Disconnect any peripheral devices (printer, monitors, and so on) from the

computer.

4. Disconnect the AC power cord from its power source and from the computer

(Figure 7.2-2).

Chapter 7.3 Access Cover Removal and Replacement

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

WARNING

Before removing the access cover from the COMPAQ Portable Computer, complete
the Preparation Procedure in Section 7.2. If you have not completed the
preparation portion of this section, do so before continuing this procedure.

Failure to disconnect the computer from all AC voltage sources can cause
dangerous voltages to be present on the power supply and monitor. Even when
the ON/OFF switch is set to the OFF position, any electrically conductive
material in this area could cause severe electrical shock.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

To remove the access cover:

1. Complete the Preparation Procedure in Section 7.2.

2. Place the curved end of the access cover lever in the first notch located

on the edge of the access cover near the handle. The access cover lever

(PN 102935-001) is found with the test cable and plugs in the

Maintenance and Service Guide Kit. Pry the corner of the access cover

away from the computer and insert a plastic card into the connecting seam

(Figure 7.3-1).

3. Continue this procedure across the edge of the access cover, prying up at

each notch, until the cover pops loose.

4. Once the cover is loosened, move it slightly back and lift it away from

the computer.

5. To remove the other access panel, turn the computer over so that the

remaining cover is facing up. Repeat Steps 1 through 4.

To replace either the top or bottom access cover, position the tabs on the
cover under the bezel, and snap the cover onto the case.

Chapter 7.4 Board Slots Access Plate Removal and Replacement

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

WARNING

Failure to disconnect the computer from all AC voltage sources can cause
dangerous voltages to be present on the power supply and monitor. Even when
the ON/OFF switch is set to the OFF position, any electrically conductive
material in this area could cause severe electrical shock.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

To remove the board slots access plate:

1. Complete the Access Cover Removal procedure in Section 7.3.

2. Loosen (DO NOT REMOVE) the six screws and the 1/4 inch hex nut that secure

the board slots access plate (Figure 7.4-1).

3. Remove the board slots access plate by gently lifting the cover straight

up from the system chassis and lifting it away from the computer.

To replace the board slots access plate, reverse Steps 1 through 3.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Ensure that the retainers on the bottom side of the board slots access plate
fit securely onto each board installed in your computer. If you changed to a
board of a different height, rotate the retainers to match the height of the
board. If the retainers are not rotated, serious internal damage may result!

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Chapter 7.5 High Voltage Access Plate Removal and Replacement

To remove and replace the high voltage access plate:

1. Complete the Access Cover Removal Procedure (see Section 7.3).

2. Loosen (DO NOT REMOVE) the six screws and the two 1/4 inch nuts securing

the high voltage access plate (Figure 7.5-1). Slide the metal cover

toward the rear of the computer and lift it off.

To replace the high voltage access plate, reverse Steps 1 and 2.

Chapter 7.6 Mass Storage Device Access Plate Removal and Replacement

To remove the mass storage device access plate:

1. Remove the board slots access plate (see Section 7.4).

2. Loosen (DO NOT REMOVE) the five retaining screws that secure the mass

storage device access plate (Figure 7.6-1).

3. Remove the disk drive mounting screws and slide the access plate toward

the rear of the computer (Figure 7.6-1). Lift it off and set it aside.

To replace the mass storage device access plate, reverse Steps 1 through 3.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

In the COMPAQ PORTABLE 286 Personal Computer, the mounting screw on the fixed
disk drive side is longer than the other two mounting screws. To avoid
damaging the diskette drives, replace the longer screw in its original
location.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Chapter 7.7 System Board Connector Access Plate Removal and Replacement

To remove the system board connector access plate:

1. Remove the bottom access cover (see Section 7.3).

2. Place the computer so that the display is facing downward against the work

surface.

3. Locate and loosen (DO NOT REMOVE) the two screws that secure the system

board connector access plate.

4. Remove the access plate by sliding it slightly down and away from the

chassis (Figure 7.7-1).

To replace the system board connector access plate, reverse Steps 1 through 4.

Chapter 7.8 Power Supply Subsystem Removal and Replacement

For COMPAQ Portable or COMPAQ PLUS Personal Computers with a serial number
1524020B0001 or above and for COMPAQ PORTABLE 286 Personal Computers, follow
the procedures beginning in the COMPAQ PORTABLE 286 Power Supply Subassembly
Removal and Replacement section.

If the COMPAQ Portable or COMPAQ PLUS Personal Computer has a serial number
below 1524020B0001, follow the procedures below.

Figure 7.8-1 shows the location of the power supply subsystem.

COMPAQ Portable Power Supply Subsystem Removal and Replacement (for COMPAQ
Portable and COMPAQ PLUS Personal Computers with serial numbers
below 1524020B0001)

This power supply subsystem consists of the AC line fuse, the power switch
filter assembly, the power supply assembly, and the fan/bracket assembly.

COMPAQ Portable AC Line Fuse Removal and Replacement

To remove and replace the COMPAQ Portable AC line fuse:

1. Complete the Preparation Procedure (see Section 7.2).

2. Insert a flat bladed screwdriver along the bottom edge of the fuse box.

Pry outward with enough pressure to force the fuse box out of the casing

(Figure 7.8-2).

3. Once the fuse box is out, you will see a spare fuse in a holding area in

the fuse box (Figure 7.8-3). Lift out the defective fuse and replace it

with the spare fuse.

4. Slide the fuse box back into the case. With your thumb, press the cover

in until you feel it snap into place.

5. Reconnect all cables removed earlier.

NOTE: If the fuse has been replaced a number of times, the fuse clips may
lose their tension and not make good contact with the fuse. Check the fuse
clips and, if necessary, squeeze them gently with needlenosed pliers or
replace the assembly.

COMPAQ Portable Power Switch Filter Assembly Removal and Replacement

To remove the COMPAQ Portable power switch filter assembly:

1. Complete the High Voltage Access Plate Removal procedure (see

Section 7.5).

2. Remove the two screws that are holding the power switch filter assembly

(Figure 7.8-4).

3. Lift the assembly out and place it on the chassis.

4. Disconnect the power switch filter assembly connector from the power

supply assembly (Figure 7.8-5).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires will make the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

5. Remove the 1/4 inch hex nut that secures the power switch filter assembly

ground strap, and carefully lift the power switch filter assembly up and

away from the computer (Figure 7.8-6).

To replace the power switch filter assembly, reverse Steps 1 through 5.

COMPAQ Portable Power Supply Assembly Removal and Replacement

To remove the COMPAQ Portable power supply assembly:

1. Complete the High Voltage Access Plate Removal procedure (see

Section 7.5).

2. Remove the power switch filter assembly.

3. Disconnect the remaining fan connector from the power supply assembly

(Figure 7.8-7).

4. Using the two piece socket tool and the socket or a 5/16 inch box end

wrench, unscrew the spring loaded hexhead screw that is on the lower

corner of the power supply assembly (Figure 7.8-8).

5. Partially close the access door panel to allow the standoffs to disengage

the chassis.

6. Slide the power supply assembly toward the rear of the computer to

disengage the three standoffs from the slots in the chassis. This

releases the power supply assembly from the chassis.

7. Carefully lift the power supply assembly out of the chassis and gently

remove all remaining connectors from the board (Figure 7.8-9).

To replace the power supply assembly, reverse Steps 1 through 7.

NOTE: Be sure to securely tighten the mounting screw with the 5/16 inch box
end wrench because using only the socket extension wrench may not securely
tighten the mounting screw (thereby causing grounding problems).

COMPAQ Portable Fan/Bracket Assembly Removal and Replacement

To remove the fan/bracket assembly:

1. Complete the High Voltage Access Plate Removal Procedure

(see Section 7.5).

2. Disconnect the fan power connector from the power supply (Figure 7.8-10).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

3. Open the access door panel.

4. Remove the four screws that hold the fan/bracket assembly in place

(Figure 7.8-11).

5. Carefully lift the fan/bracket assembly out and away from the chassis

(Figure 7.8-12). Route the fan cable through the access hole and chassis.

To replace the fan/bracket assembly, reverse Steps 1 through 5.

COMPAQ PORTABLE 286 Power Supply Subsystem Removal and Replacement (also for
COMPAQ Portable and COMPAQ PLUS Personal Computers with serial
number 1524020B0001 or above)

The power supply subsystem consists of the AC line fuse, the fan/bracket

assembly, the power supply assembly, and the power switch filter assembly.

COMPAQ PORTABLE 286 AC Line Fuse Removal and Replacement

To remove the AC line fuse:

1. Complete the Preparation Procedure (see Section 7.2).

2. Slide the access door panel open to expose the power switch filter

assembly (Figure 7.8-13).

3. Insert a flat bladed screwdriver along the bottom edge of the fuse box.

Pry outward with enough pressure to force the fuse box out of the casing

(Figure 7.8-14).

4. Once the fuse box is out, you will see a spare fuse in a holding area in

the fuse box (Figure 7.8-15). Lift out the defective fuse, and replace it

with the spare one.

NOTE: If the fuse has been replaced a number of times, the fuse clips may
lose their tension and not make good contact with the fuse. Check the fuse
clips and, if necessary, squeeze them with needlenosed pliers, or replace
the assembly.

5. Slide the fuse box back into place. Press the cover until you feel it

snap into place.

COMPAQ PORTABLE 286 Fan/Bracket Assembly Removal and Replacement

To remove the fan/bracket assembly:

1. Complete the High Voltage Access Plate Removal procedure (see

Section 7.5).

2. Open the access door panel.

3. Loosen (DO NOT REMOVE) the screw that secures the fan/bracket assembly to

the chassis (at the rear of the monitor).

4. Now remove the remaining three screws that secure the fan/bracket assembly

in place (Figure 7.8-16).

5. Disconnect the fan/bracket assembly power connector from the power supply

assembly (Figure 7.8-17). Cut the tie wrap that holds the fan power cord

to the monitor enclosure.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

6. Lift the fan/bracket assembly up and out of the computer (Figure 7.8-18).

To replace the fan/bracket assembly, reverse Steps 1 through 6.

COMPAQ PORTABLE 286 Power Supply Assembly Removal and Replacement

To remove the Power Supply Assembly:

1. Complete the Fan/Bracket Assembly Removal procedure.

2. Carefully disconnect the power switch filter assembly connector from the

power supply assembly (Figure 7.8-19).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

3. Using the special two piece socket tool or 5/16 inch box end wrench,

loosen the power supply mounting screw from the upper (or lower) right

corner of the power supply assembly (Figure 7.8-20).

4. Partially close the access door panel to allow the standoffs to disengage

the chassis.

5. Slide the power supply assembly toward the back of the chassis until the

board standoffs disengage. This releases the power supply assembly

from the chassis.

6. Carefully lift the power supply assembly out of the chassis and gently

disconnect the remaining connector from the board (Figure 7.8-21).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires will make the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

To replace the power supply assembly, reverse Steps 1 through 6.

NOTE: Be sure to securely tighten the mounting screw with the 5/16 inch box
end wrench because using only the socket extension wrench may not securely
tighten the mounting screw (thereby causing grounding problems).

COMPAQ PORTABLE 286 Power Switch Filter Assembly Removal and Replacement

To remove the power switch filter assembly:

1. Complete the Fan/Bracket Assembly Removal procedure.

2. Remove the two screws holding the power switch filter assembly in place

(Figure 7.8-22).

3. Remove the 1/4 inch hex nut and the tie wrap that hold the power switch

ground cable.

4. Lift the power switch filter assembly out and place it on the chassis

(Figure 7.8-23).

5. Disconnect the power switch filter assembly connector from the power

supply assembly (Figure 7.8-24).

To replace the power switch filter assembly, reverse Steps 1 through 5.

Chapter 7.9 Controller and Expansion Board Removal and Replacement

Before beginning this procedure, become familiar with the locations of
controller and Controller Board expansion boards and their specific signal
cables, if applicable (Figure 7.9-1).

Fixed Disk Drive Controller Board Removal and Replacement

To remove the fixed disk drive controller board:

1. Complete the Board Slots Access Plate Removal procedure (see Section 7.4).

2. Disconnect the two fixed disk drive controller board signal cables by

pulling the connectors away from the board (Figure 7.9-2).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wire makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

3. Remove the retaining screw that secures the fixed disk drive controller

board. Gently pull the board up and out of its J103 socket on the system

board and out of the computer. (Figure 7.9-3).

NOTE: Controller and expansion board retaining screws may be located either
inside or outside the chassis.

To replace the fixed disk drive controller board, reverse Steps 1 through 3.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Ensure that the retainers on the bottom side of the board slots access plate
fit securely onto each board installed in your computer. If you changed to a
board of a different height, rotate the retainers to match the height of the
board. If the retainers are not rotated, serious internal damage may result!

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Video Display Controller Board Removal and Replacement

To remove the video display controller board:

1. Complete the Board Slots Access Plate Removal procedure (see Section 7.4).

2. Disconnect the fixed disk drive controller board signal cables, if

installed (Figure 7.9-2).

3. Remove the retaining screw that secures the video display controller

board and disconnects the video display signal cable

(Figure 7.9-4).

NOTE: Controller and expansion board retaining screws may be located either
inside or outside the chassis.

A tie wrap secures the video display signal cable. Remove this tie wrap
before disconnecting the signal cable from the video display controller board.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires damages the
cable.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

4. Gently pull the video display controller board up and out of its socket

(J102 on COMPAQ PORTABLE 286 Personal Computers; J104 on COMPAQ Portable

and COMPAQ PLUS Personal Computers) on the system board and out of the

computer (Figure 7.9-5).

To replace the video display controller board, reverse Steps 1 through 4.

NOTE: Be sure that the board is in the board guide on the left.

Diskette/Tape Controller Board Removal and Replacement

To remove the diskette/tape controller board:

1. Complete the Board Slots Access Plate Removal procedure (see Section 7.4).

2. Disconnect the fixed disk drive controller board signal cables, if

installed (Figure 7.9-2).

3. Disconnect the diskette/tape controller board signal cable by pressing the

finger tabs (if available) that are located on both sides of the connector

(Figure 7.9-6).

4. Remove the retaining screw that secures the diskette/tape controller

board.

5. Gently pull the board up and out of its socket (J101 on COMPAQ PORTABLE

286 Personal Computers; J105 on COMPAQ Portable and COMPAQ PLUS Personal

Computers) on the system board. (Figure 7.9-7).

NOTE: Controller and expansion board retaining screws may be located either
inside or outside the chassis.

To replace the diskette/tape controller board, reverse Steps 1 through 5.

NOTE: Ensure that the retainers on the bottom side of the board slots access
plate fit securely onto each board installed in the computer. Also be sure
that the board is in the board guide on the left.

Expansion Board Removal and Replacement

To remove COMPAQ memory expansion boards or any other expansion boards
installed in the computer:

1. Complete the Board Slots Access Plate Removal procedure (see Section 7.4).

2. Remove any signal cables attached to the board.

3. Remove the retaining screw that secures the board to the system chassis.

4. Gently pull the particular expansion board up and out of its socket on the

system board. Remove the board from the computer. (Figure 7.9-8).

To replace the expansion board, reverse Steps 1 through 4.

NOTE: Ensure that the retainers on the bottom side of the board slots access
plate fit securely onto each board installed in the computer. If you changed
to a board of a different height, rotate the retainers to match the height of
the board.

Chapter 7.10 System Board and Memory Option Removal and Replacement

Removal and replacement procedures for both the system board and associated
COMPAQ memory options (including ROMs) are included in this section.

Although it is possible to remove and replace memory options in a COMPAQ
Portable and COMPAQ PLUS Personal Computer without removing the system board,
it is not recommended because of the limited amount of space inside the
chassis. Removing the system board allows close examination of memory chips.

System Board Removal and Replacement

To remove the system board:

1. Complete removal procedures for all installed controller and expansion

boards (see Section 7.9).

2. Remove the bottom access cover (see Section 7.3).

3. If you are removing a COMPAQ PORTABLE 286 system board, disconnect the

security lock switch connector and storage device power cables (see

Sections 7.11 and 7.14).

4. Remove the following system board connectors:

o Keyboard connector

o System power connector

o Monitor power connector (COMPAQ PORTABLE 286 only)

o Battery connector (COMPAQ PORTABLE 286 only)

o Speaker connector

See Figure 7.10-1 for the location of each of these connectors.

NOTE: Once the battery connector has been disconnected from the COMPAQ
PORTABLE 286 system board, reset the time function found in MS-DOS or in
SETUP. SETUP is found on both the USER PROGRAMS Diskette and the latest
version of the DIAGNOSTICS Diskette.

5. Locate and remove the four screws that secure the system board mounting

bracket to the system chassis (Figure 7.10-2).

6. Slide the system board to the rear, lifting it slightly upward, so that

the six nylon standoffs (attached to the bottom of the system board)

clear the mounting holes. Carefully lift the system board out of the

chassis (Figure 7.10-3).

To replace the system board, reverse Steps 1 through 6.

Memory Option Removal and Replacement

To remove an optional memory or ROM:

1. Remove the system board.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

The pins on the chips bend easily. The notch or PIN 1 locator dot on the chip
should be inserted so that it faces toward the board slots. Bending the pins
can make the chip unusable. Alter insertion, carefully check that all pins
are in the socket and that none are bent or are outside of the socket.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

NOTE: The system boards for the COMPAQ Portable and COMPAQ PLUS are quite
different from the system board for the COMPAQ PORTABLE 286. Take time to
become familiar with the system boards. Pay special attention to the
different RAM bank locations and ROM locations (Figures 7.10-4 and 7.10-5).

2. Using the special IC removal tool, remove the defective memory or ROM

chip(s) (Figure 7.10-6).

3. Using the special IC insertion tool, replace the defective memory or ROM

chip(s) (Figure 7.10-7).

4. To replace the system board, reverse Steps 1 through 6, which are

presented at the beginning of this section.

NOTE: After replacing any defective component, run the latest version of
DIAGNOSTICS to verify that the replaced component functions properly.

Chapter 7.11 Mass Storage Device Removal and Replacement

Mass storage devices are installed in two drive enclosures. The device next
to the monitor assembly is referred to as Enclosure A, and the other is
referred to as Enclosure B (Figure 7.11-1).

The mass storage devices have different configurations depending on the
computer model. Determine the configuration of the mass storage devices.

COMPAQ Portable and COMPAQ PLUS Personal Computers

o Enclosure A contains: diskette drive ONLY.
o Enclosure B contains: diskette drive or fixed disk drive.

COMPAQ PORTABLE 286 Personal Computers

o Enclosure A contains: diskette drive and blank panel or diskette drive and

tape drive or two diskette drives

o Enclosure B contains: fixed disk drive ONLY.

Mass Storage Device Enclosure B Removal and Replacement

To remove Enclosure B:

1. Complete the removal procedures for all installed controller and expansion

boards (see Section 7.9).

2. Remove the mass storage device access plate (see Section 7.6).

3. Disconnect the power cable(s) from the mass storage device.

4. Disconnect the fixed disk drive power connector from its J113 socket on

the COMPAQ PORTABLE 286 system board (Figure 7.11-2).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

5. Raise the computer as shown in Figure 7.11-3.

6. Remove the two shock mount screws.

7. Return the computer to its flat position on the work surface.

8. Remove the top mounting screw from Enclosure B (Figure 7.11-4).

9. Slide Enclosure B towards the rear of the system chassis, lift it from the

chassis, and let it rest on the side of the chassis.

10. If Enclosure B contains a fixed disk drive, disconnect the fixed disk

drive LED connector from the front of the enclosure and remove this
enclosure from the system chassis (Figure 7.11-5).

NOTE: If Enclosure B is a fixed disk drive replacement for a COMPAQ Portable
or COMPAQ PLUS Personal Computer, it may be necessary to remove the face
plate/LED assembly that is attached to the chassis. To do this, remove the
hex nut at the bottom of the face plate/LED assembly before removing
Enclosure B.

To replace Enclosure B, reverse Steps 1 through 10.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

When removing the enclosure, do not bend the drive ground strap located on the
top front shock mount of each enclosure.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Mass Storage Device Enclosure A Removal and Replacement

To remove Enclosure A:

1. Complete the removal procedures for all installed controller and expansion

boards (see Section 7.9).

2. Remove the mass storage device access plate (see Section 7.11).

3. Disconnect the power cables from the mass storage device(s).

4. Disconnect any power cables that may be connected to sockets J114 or

J115 on the system board (Figure 7.11-6) of a COMPAQ PORTABLE 286

Personal Computer.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

Pull only on the connector, do not pry. Pulling on the wires makes the
connector grip the pins tighter, which will damage the connector.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

5. Raise the computer as shown in Figure 7.11-7.

6. Remove the bottom two (or three) Enclosure A mounting screws

(Figure 7.11-7).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

On COMPAQ PORTABLE 286 Personal Computers, three bottom mounting screws are
used to secure Enclosure A. These screws are shorter than those used in
Enclosure B. To avoid damaging the drives, return the correct screws to the
correct locations when replacing the drive assemblies.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

7. Return the computer to its flat position on the work surface and remove

the top Enclosure A mounting screw (Figure 7.11-8).

8. Slide Enclosure A to the rear of the computer and lift it up and out of

the computer (Figure 7.11-9).

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

When removing the enclosure do not bend the ground strap located on the top

CAUTION

front shock mount of each enclosure.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

NOTE: If removing a diskette drive or tape drive in a COMPAQ PORTABLE 286,
continue with the procedures in this section.

At this point, determine which device in Enclosure A is to be removed. This
guide refers to the device closest to the monitor as 1A and the other device
as 2A (Figure 7.11-10).

NOTE: Step 9 describes removing Device 2A. Step 10 describes removing
Device 1A.

To remove Device 2A from the enclosure:

9. Remove the four mounting screws from the bottom (or the side nearest

Enclosure B) that secure the device to the enclosure and slide it out of

the enclosure (Figure 7.11-11).

To replace Device 2A, reverse Step 9.

NOTE: Replace the drive insulator pad if it was removed when replacing
devices in this enclosure.

To remove Device 1A from the enclosure:

10. Remove the two mounting screws from each side of Enclosure A and slide

the device out of the enclosure (Figure 7.11-12).

To replace Device 1A, reverse Step 10.

To replace Enclosure A, reverse Steps 1 through 8.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

CAUTION

On COMPAQ PORTABLE 286 Personal Computers, three bottom mounting screws are
used to secure Enclosure A. These screws are shorter than those used in
Enclosure B. To avoid damaging the drives, return the correct screws to the
correct locations when replacing the drive assemblies.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Chapter 7.12 Monitor Enclosure Removal and Replacement

The redesign of the COMPAQ Portable Computer chassis required a redesign of
the monitor enclosure (Figure 7.12-1).

This new design of the monitor enclosure (PN 105034-001 no longer
available) is used in COMPAQ Portable Computers with the serial number
1524020B0001 and above, and all COMPAQ PORTABLE 286 Personal Computers.

DO NOT use the previous monitor enclosure (PN 100481-001 no longer
available) in the computers mentioned above.

NOTE: To prevent possible mistakes in replacing the monitor enclosure, a

tab has been placed on the chassis near the fan/bracket assembly to
allow ONLY monitor enclosures with this new design to be installed.
Using the previous monitor enclosure may result in power supply failure.

To remove the monitor enclosure assembly:

1. Complete the removal procedures for all installed controller and option

boards (see Section 7.9).

2. Remove mass storage device Enclosure A (see Section 7.11).

3. Remove the fan/bracket assembly (see Section 7.8).

NOTE: For COMPAQ Portable and COMPAQ PLUS Personal Computers with serial

numbers below 1524020B0001, it is necessary to remove the power
switch filter assembly INSTEAD of the fan/bracket assembly. You do
not have to remove the power supply.

4. Using the special two piece socket power supply removal tool or box end

wrench, remove the two screws that secure the monitor enclosure to the

wall of the power supply subsystem area (Figure 7.12-2).

5. Place the computer on the work surface so that the handle is facing up and

the side of the computer with feet is facing you.

6. Remove the system board connector access plate (see Section 7.7).

7. Disconnect the speaker connector from the system board. Cut any cable

ties that hold the speaker cable in place (Figure 7.12-3).

NOTE: On the COMPAQ PORTABLE 286, remove the monitor power connector from

the system board.

8. Locate and remove the two screws that secure the monitor enclosure to the