Compaq 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

Depth

Width

8.5 in. (215.9 mm)

16.0 in. (406.4 mm)

20.0 in. (512.8 mm)

Weight:

With one diskette drive

With two diskette drives

With one diskette drive and one fixed disk drive

Power Requirements:

Line Voltage

Line Frequency

Power

Current

27.5 lb (12.5 kg)

30.5 lb (13.5 kg)

31 lb (14 kg)

115 VAC

60 Hz

3 amps

Power Cable:

Length

Gauge

79 in. (2006.6 mm)

18 AWG

Environmental Requirements:

Temperature:

Operating

Nonoperating

Humidity:

Operating

Nonoperating

50oF to 104oF (10oC to 40oC)


20% to 80% (noncondensing)


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

Keyboard Specifications

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

Dimensions:

Height

Depth

Width

1.5 in. (38.1 mm)

7.06 in. (179.3 mm)

18.25 in. (463.6 mm)

83 Number of Keys

Keyboard Cable:

Length

Gauge

72 in. (1828.8 mm)

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

Depth

Width

1.625 in. (40.625 mm)

8.29 in. (210.6 mm)

5.88 in. (149.4 mm)

Weight

Data Transfer Rate

Media

Number of Tracks

3.2 lb (1.45 kg)

250 Kb/s

48 TPI Double Sided Double Density Diskettes

40

Tracks per Inch 48

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

10 Megabyte Fixed Disk Drive Specifications

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

Dimensions:

Height

Width

Depth

1.69 in. (4.33 cm)

5.875 in. (14.6875 cm)

8.25 in. (20.625 cm)

Weight

Media

3.5 lb (1.575 kg)

Fixed plated media

Tracks per Inch

Number of Cylinders

Data Transfer Rate 5 Mb/s

Average Access Time 105 ms

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

Power Supply Specifications

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

Input Requirements:

AC Voltage RMS:

Domestic

International

Line Frequency

Line Voltage

Current

102 - 132 VAC

204 - 264 VAC

47 to 62 Hz

120 VAC, 60 Hz

2 amps maximum at input

(3 amps depending on fuse rating)

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

VDC Output: Nominal Current Current Regulation

Voltage

VDC

Amps

Minimum

Amps

Maximum *

Tolerance

Percent

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

+ 5.0

2.0

10.0

5

- 5.0

+ 12.0

0.0

1.0

0.5

5.0

5

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

Depth

Width

8.5 in. (215.9 mm)

16 in. (406.4 mm)

20 in. (508.0 mm)

Weight:

Model 1

Model 2

Model 3

Power Requirements:

Line Voltage

Line Frequency

600

305

30 lb (13.5 kg)

33 lb (15.0 kg)

34 lb (15.4 kg)

115 VAC

60 Hz

Power

Current

Humidity:

Operating

Nonoperating

4 amps

Power Cable:

Length

Gauge

72 in. (1828.8 mm)

18 AWG

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

Environmental Requirements

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

Temperature:

Operating

Nonoperating





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

Keyboard Specifications

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

Dimensions:

Height

Depth

Width

1.5 in. (38.1 mm)

7.06 in. (179.3 mm)

18.25 in. (436.6 mm)

84 Number of Keys

Keyboard Cable:

Length

Gauge

72 in. (1828.8 mm)

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

Depth

Width

1.7 in. (4.33 cm)

4.1 in. (10.41 cm)

5.75 in. (14.61 cm)

Weight

Media

Number of Data Heads

Number of Cylinders

1.8 lb (0.8 kg)

Fixed plated media

4

615

Average Access Time

Data Transfer Rate

105 ms (maximum)

5 Mb/s

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

10 Megabyte Tape Drive Specifications

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

Dimensions:

Height

Depth

Width

1.65 in. (4.29 cm)

8 in. (20 cm)

5.65 in. (14.76 cm)

Weight

Media

1.7 lb (0.765 kg)

DC 1000 Manufactured by 3M Corporation or equivalent

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

1.2 Megabyte Diskette Drive Specifications

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

Dimensions:

Height

Depth

Width

1.65 in. (4.29 cm)

8.25 in. (20.625 cm)

5.88 in. (14.7 cm)

Weight

Media

3.2 lb (1.44 kg)

96 and 48 TPI Double Sided High Density Diskettes

Tracks per Inch

Number of Tracks

96

80 (When formatted with MS-DOS)

Data Transfer Rate 300/500 Kb/s

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

360 Kbyte Diskette Drive Specifications

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

Dimensions:

Height

Depth

Width

1.60 in. (4.0625 cm)

8.0 in. (20.625 cm)

5.8 in. (14.7 cm)

Weight

Media

Tracks per Inch

Number of Tracks

3.2 lb (1.44 kg)

40 TPI Double Sided Double Density Diskettes

48

40 (When formatted with MS-DOS)

Data Transfer Rate 250 Kb/s

Power supply specifications:

Input Requirements:

Line

Voltage

Line Fuse

Line Frequency

102 to 132 VAC, single phase

180 to 264 VAC, single phase

3 amps 250V fuse for 115 VAC operation,

2.5 amps for 220 VAC operation

47 to 62 Hz

Cooling

Current

Forced air provided by 16 VDC fan

2 amps, maximum at input voltage of 120 VAC,

60 Hz

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

VDC Output: Nominal

Voltage

Current

Amps

Current

Amps

Regulation

Tolerance

VDC Minimum Maximum * Percent

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

+ 5.0

- 5.0

1.5

0.0

15.0

0.5

2

5

+ 12.25

+ 12.25

1.0

0.0

5.0

1.5

2

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


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


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,

1 Short

System ROM

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

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

Error

None RAM Failure *

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

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.

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


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

402 - Monochrome Display 1 Long, Monochrome Display Controller Board

Controller Failure 2 Short

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

501 - Display Controller

Failure

1 Long,

2 Short

Video Display or Video Controller

Board

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

601 - Diskette Controller None Diskette Controller Board

Error

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

1780 - Disk 0 Failure None Fixed Disk Drive

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

1782 - Disk Controller

Failure

None Fixed Disk Drive

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

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: speed

COMMON (6 MHz)

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

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

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


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

Audible 1 Beep Power On successful

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

1XX 1 Long, System ROM or System Board

1 Short

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

XXYY 20X None Failure

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

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

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

4XX None Diskette/Printer Board

1 Long,

2 Short

Video Display Unit or Video Controller

Board

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

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

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

Code

Error

Description

Required

Action

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

Processor

1yy - xx

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

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

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

102 - 01 287 Coprocessor initial status word incorrect

The following steps apply to error codes 102 - 01 through 102 - 15:

102 - 02

102 - 03

287 Coprocessor initial control word incorrect

287 Coprocessor tag word not all ones

1.

Replace the 287 Coprocessor.

2.

Replace the system board.

102 - 04

102 - 05

102 - 06

102 - 07

287 Coprocessor tag word not all zeros

287 Coprocessor exchange command failed

287 Coprocessor masked exception incorrectly handled

287 Coprocessor unmasked exception codes incorrectly handled

102 - 08

102 - 15 287 socket is unoccupied, or 287 is inoperative

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

Error Error Required

Code Description Action

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

103 - 01 8237 DMA page registers test

Replace the system board for error codes 103 - 01 through 113 - 01.

103 - 02

287 Coprocessor wrong mask bit set in status register

103 - 03

8237 DMA byte controller test failed

8237 DMA word controller test failed

104 - 01

104 - 02

8259 interrupt controller master test failed

8259 interrupt controller slave test failed

104 - 03

105 - 01

105 - 02

105 - 03

105 - 04

105 - 05

105 - 06

105 - 07

105 - 08

8259 software RTC is inoperative

Port bit 6 not at zero





Port bit 5 not at one



105 - 09 Port bit 0 not at one

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

Error

Code

Error

Description

Required

Action

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

Processor

1yy - xx

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

106 - 01 8042 keyboard controller self test failed

Replace the system board for error codes 103 - 01 through 113 - 01.

107 - 01

108 - 02

CMOS RAM test failed

CMOS interrupt test failed

109 - 01

109 - 02

110 - 01

110 - 02

111 - 01

112 - 01

112 - 02

112 - 03

CMOS clock load data test failed

CMOS clock rollover test failed

8254 load data test failed

8254 dynamic test failed

Refresh detect test failed

Speed test slow mode out of range

Speed test mixed mode out of range

Speed test fast mode out of range

112 - 04

112 - 05

Speed test unable to enter slow mode

Speed test unable to enter mixed mode

112 - 06 Speed test unable to enter fast mode

Speed test system error 112 - 07

113 - 01 Protected mode test failed

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

114 - 01 Speaker test failed 1.

Replace the speaker.

2.


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



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

Memory *

2yy - xx

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

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

201 - 02 Memory machine type test failed codes 201 - 01 through 202 - 01:

(Error during saving test program memory):

201 - 03 Memory machine ID & type tests failed

1.

Replace VDU controller board.

2.

Replace the system ROM.

3.


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 memory in write/read test

1.

Replace the defective memory chip if an error code is accompanied by an XX000B YYZZ

203 - 03 Error during restore of program in write/read test

Memory address test failed

2.

code.


204 - 01

204 - 02

204 - 03

Error during saving program memory in address test

Error during restore of program memory address test

Walking I/O test failed 205 - 01

205 - 02

301 - 03

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

Code

Error

Description

Required

Action

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

Keyboard

3yy - xx

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

301 - 01 Keyboard short test, 8042 self test failed


301 - 02 Keyboard short test, interface test failed

Keyboard short test, echo test failed

1.

Replace the keyboard.

2.


301 - 04

302 - 01

303 - 01

303 - 02

Keyboard short test, keyboard reset failed

Keyboard long test failed

Keyboard LED test, 8042 self test failed

Keyboard LED test, reset test failed

303 - 03

303 - 04

303 - 05

303 - 06

Keyboard LED test, reset test failed

Keyboard LED test, LED command test failed



303 - 07

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

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



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

Printer

4yy - xx

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

401 - 01 Printer failed or not The following steps apply to error connected codes 401 - 01 through 403 - 01:

402 - 01

402 - 02

402 - 03

402 - 04

402 - 05

Printer data register failed

Printer controller register failed

Printer data and controller register failed

Printer loopback failed

1.

If a printer is connected, be sure it is turned ON and in the online mode.

2.

Check switch 2 on the diskette/tape controller board

(see Chapter 8). *

3.

Replace the printer and/or the printer controller cable.

4.

Replace the diskette/tape controller board. *

5.


402 - 06

Printer loopback and data register failed

Printer loopback and controller register failed

* 286 based COMPAQ Personal

Computers only

402 - 07

402 - 08

Printer loopback, data, and controller register failed

Printer interrupt test failed

402 - 09 Printer interrupt and data failed

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



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

402 - 10 Printer interrupt and controller register failed


402 - 11

402 - 12

402 - 13

402 - 14

402 - 15

402 - 16

403 - 01 Printer pattern test failed

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

Error

Code

Error

Description

Required

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

503 - 01

504 - 01

VDU attribute test failed

VDU character set test failed

1.

Replace the VDU controller board.

2.

Replace the VDU signal cable.

3.

Replace VDU subassembly.

4.


505 - 01

506 - 01

VDU 9 x 14 character cell test

VDU 80 x 25 mode 8 x 8 character cell test failed

507 - 01

Printer interrupt data, and controller register failed

1.

If a printer is connected, be sure it is turned ON and in the online mode.

2.

Check switch 2 on the Printer interrupt and loopback failed diskette/tape controller board

(see Chapter 8). *

Printer interrupt, loopback, 3.

Replace the printer and/or the and data register failed printer controller cable.

Printer interrupt, loopback, and controller register failed

4.


5.



Computers only Printer interrupt, loopback, data, and controller register failed

Printer unexpected interrupt received

508 - 01

509 - 01

510 - 01

VDU 40 x 25 mode test failed

VDU 320 x 200 mode color set 0 test failed

VDU 320 x 200 mode color set 1 test failed

VDU 640 x 200 mode test failed

511 - 01

512 - 01

VDU screen memory page test failed

VDU gray scale test failed

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



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

516 - 01 Lightpen text mode test failed - no response


516 - 0 Lightpen text mode test failed - invalid response

1.

2.

Replace the lightpen.

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

602 - xx

603 - xx

604 - xx

605 - xx

Diskette drive read

Diskette drive write/read/ compare

Diskette drive random seek drive

Diskette drive ID media test

1.

Check shunt jumper J2 setting on the diskette/tape controller board (see

Chapter 8). *

2.


3.

Replace the diskette drive power and signal cables.

4.

Replace the diskette drive assembly.

5.


606 - xx

607 - xx

Diskette drive speed test

Diskette drive wrap test


Computers only

608 - xx Diskette drive write protect test

609 - xx Diskette drive reset controller test

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



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

Diskette Drive

6yy - xx

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

610 - xx Diskette drive change line The following steps apply to all test 6yy - xx related error codes.

610 - 01

610 - 02

Exceeded maximum soft error limit

Exceeded maximum hard error limit

1.


Chapter 8). *

2.


610 - 03

610 - 04

Previously exceeded max soft error limit

Previously exceeded max hard error limit

Failed to reset controller

Fatal error while reading

3.


4.


5.



Computers only

610 - 05

610 - 06

610 - 07 Fatal error while writing

610 - 08 Failed compare of write/ read/compare

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



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

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

610 - 20

610 - 21 **

610 - 22

610 - 23

Failed to get drive type

Failed to get change line status

Failed to clear change

Failed to set drive type in

ID media

1.


Chapter 8). *

2.


3.


4.


5.


610 - 24 Failed to read media

610 - 25 Failed to verify media


Computers only

610 - 26 Failed to read media in speed test

** The following applies to

286 based computers:

610 - 27

610 - 28

610 - 29

Failed speed limits

Failed write protect test

Failed to read media in file write test

For a 1.2 megabyte diskette drive, replace the diskette drive.

For a 360 Kbyte diskette drive, a drive modification has not been performed.

See Service

Bulletin 25.

610 - 40 Cylinder 0 Error

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

Error

Code

Error

Description

Required

Action

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

Serial

11yy - xx

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

1101 - 01 Serial Port Test, UART

DLAB bit failure

The following steps apply to all

11yy - xx related error codes:

1101 - 02

1101 - 03

1101 - 04

1101 - 05

1101 - 06

1101 - 07

1101 - 08

1101 - 09

Serial Port Test, Line input or UART fault

Serial Port Test, Address line fault

Serial Port Test, Data line fault

Serial Port Test, UART control signal

Serial Port Test, ART THRE bit failure

Serial Port Test, UART DATA

READY bit failure

Serial Port Test, UART

TX/RX buffer failure

Serial Port Test, INTERRUPT circuit failure

1.

Check diskette/tape controller

3.

board for proper shunt jumper settings (see Chapter 8). *

2.

Replace the diskette/tape controller board.



Computers only

1101 - 10 Serial Port Test, COM 1 set to interrupt 3

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



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

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

1101 - 13

1101 - 14

Serial Port Test,

DRIVER/RECEIVER control signal failure

1.

Check diskette/tape controller board for proper shunt jumper settings (see Chapter 8). *

2.


3.


Serial Port Test, UART control signal interrupt failure

Serial Port Test,

DRIVER/RECEIVER data failure


Computers only

1109 - 01

1109 - 02

1109 - 03

1109 - 04

1109 - 05

Serial Clock Test, register initialization failure

Serial Clock Test, register rollover failure

Serial Clock Test, clock reset failure

Serial Clock Test, input line or clock failure

Serial Clock Test, address

line failure

1109 - 06 Serial Clock Test, data line failure

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



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

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

1702 - xx

1703 - xx

1704 - xx

Fixed disk drive format test

Fixed disk drive read test

Fixed disk drive write/ read/compare test

Fixed disk drive random seek test

1.

Check the fixed disk drive controller board for the proper switch setting

(see Chapter 8). *

2.

Replace the fixed disk drive signal and power cables.

3.

Replace the fixed disk drive controller board. *

4.

Replace the fixed disk drive assembly.

5.


1705 - xx Fixed disk drive controller test

Fixed disk drive ready test


Computers only

1706 - xx

1707 - xx

1708 - xx

Fixed disk drive recalibrate test

Fixed disk drive format bad track test

1709 - xx

1710 - xx

Fixed disk drive reset controller test

Fixed disk drive park head test

1714 - xx Fixed disk drive file write test

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



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

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

1716 - 01

Fixed disk drive conditional format test

Exceeded maximum soft error limit

1.


(see Chapter 8). *

2.


1716 - 02

1716 - 03

Exceeded maximum hard error limit

Previously exceeded maximum soft error limit

3.


4.


5.



Computers only

1716 - 04

1716 - 05

1716 - 06

Previously exceeded maximum hard error limit

Failed to reset controller

Fatal error while reading

1716 - 07 Fatal error while writing

1716 - 08 Failed compare of write/ read/compare test

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



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

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

1716 - 40

1716 - 41

1716 - 42

1716 - 43

1716 - 44

Failed cylinder 0

Drive not ready

Recalibrate failed fixed disk drive

Failed to format bad track

Failed fixed disk drive controller diagnostics

1.


(see Chapter 8). *

2.


3.


4.


5.


1716 - 45 Failed to get drive parameters from ROM


Computers only

1716 - 46 Invalid drive parameters found in ROM

Failed to park heads 1716 - 47

1716 - 48 Failed to move disk table to

RAM

1716 - 50 Failed file I/O test in write test

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



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

Fixed Disk Drive

17yy - xx

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

1716 - 51

1716 - 52

1716 - 53

1716 - 54

1716 - 55

1716 - 56

1716 - 57

Failed file I/O test in read test

Failed file I/O test in compare test

Failed drive/head register test

Failed digital input register test

Cylinder 1 failed

Controller RAM failed

The following steps apply to error codes 1700 - xx through 1716 - 59:

1.


(see Chapter 8). *

2.


3.


4.


5.



Computers only

1716 - 58

Controller to drive test failed

Failed to write sector buffer

1716 - 59 Failed to read sector buffer

1716 - 60 Non COMPAQ fixed disk drive controller ROM

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



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

Tape Drive

19yy - xx

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

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

19yy - xx error codes:

1902 - xx * Tape format

1903 - xx * Tape drive sensor test

1904 - xx * Tape BOT/EOT test

1905 - xx * Tape read test

1.

Replace the tape cartridge.

2.

Replace the signal cable.

3.


4.

Replace the tape drive assembly.

1906 - xx * Tape write/read/compare 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

Code

Error

Description

Required

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

1906 - 10

1906 - 11

1906 - 12

Format mode error

Drive recalibration error

Tape not servo written

1.

Replace the tape cartridge.

2.

Replace the signal cable.

3.


4.

Replace the tape drive assembly.

1906 - 13

1906 - 14

Tape not formatted

Drive timeout error


Computers only

1906 - 15

1906 - 16

1906 - 17

1906 - 18

Sensor error flag

Block locate (block ID) error

Soft error limit exceeded

Fixed error limit exceeded

1906 - 19 Write error (probably ID error)

NEC765 fatal error 1906 - 20

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 When B = 0, YY defines the defective chip row location within the low byte of the memory bank.

o When B = 1, ZZ defines 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 xx Value

Memory

Device Location

See

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

YY or ZZ

B = 0

Low

B = 1

High

B = 0

Low

B = 1

High

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

10

20

40

80

01

02

04

08

U5

U20

U25

U41

U47

U63

U70

U81

U6

U21

U26

U42

U48

U64

U71

U82

U7

U22

U27

U43

U49

U65

U72

U83

U8

U23

U28

U44

U50

U66

U73

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

Bank 0

06, 08

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

04

08

10

U20

U25

U41

U47

U21

U26

U42

U48

U22

U27

U43

U49

U23

U28

U44

U50

20

40

U63

U70

U64

U71

U65

U72

U66

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

Bank 1

1C, 1E

Bank 2

24, 26

Bank 3

2C, 2E

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

20

10

08

U4

U5

U6

U7

U13

U14

U15

U16

U22

U23

U24

U25

U31

U32

U33

U34

U40

U41

U42

U43

U49

U50

U51

U52

U58

U59

U60

U61

U67

U68

U69

U70

04

02

U8

U9

U17

U18

U26

U27

U35

U36

U44

U45

U53

U54

U62

U63

U71

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

Code

Failure

Description

Location of

Failed Chip Required Action

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

(XXYY 201)

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

0000 201 Bank 0, Parity U39 Replace System Board

0001 201

0002 201

Bank 0, Data Bit 0

Bank 0, Data Bit 1

U97 or U53 *

U87 or U53 *

Replace System Board


0004 201

0008 201

0010 201

0020 201

0040 201

0080 201

Bank 0, Data Bit 2

Bank 0, Data Bit 3

Bank 0, Data Bit 4

Bank 0, Data Bit 5

Bank 0, Data Bit 6

Bank 0, Data Bit 7

U80 or U53 *

U74 or U53 *

U70 or U45 *

U63 or U45 *

U54 or U45 *

U46 or U45 *







3000 201

3001 201

3002 201

3004 201

3008 201

3010 201

3020 201

3040 201

3080 201

2001 201

2002 201

2004 201

2008 201

2010 201

2020 201

2040 201

2080 201

1000 201

1001 201

1002 201

1004 201

Bank 1, Parity Bit

Bank 1, Data Bit 0

Bank 1, Data Bit 1

Bank 1, Data Bit 2

U38

U96 or U69 *

U86 or U69 *

U79 or U69 *





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

Code

Failure

Description

Location of

Failed Chip Required Action

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

(XXYY 201)

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

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

1020 201

1040 201

1080 201

2000 201

Bank 1, Data Bit 5

Bank 1,Data Bit 6

Bank 1, Data Bit 7

Bank 2, Parity Bit

U62 or U62 *

U53 or U62 *

U45 or U62 *

U37 or U37 *




Replace Memory Chip

Bank 2, Data Bit 0

Bank 2, Data Bit 1

Bank 2, Data Bit 2

Bank 2, Data Bit 3

Bank 2, Data Bit 4

Bank 2, Data Bit 5

Bank 2, Data Bit 6

Bank 2, Data Bit 7

U95 or U79 *

U85 or U79 *

U78 or U79 *

U72 or U79 *

U68 or U73 *

U61 or U73 *

U52 or U73 *

U44 or U73 *

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Bank 3, Parity Bit

Bank 3, Data Bit 0

Bank 3, Data Bit 1

Bank 3, Data Bit 2

Bank 3, Data Bit 3

Bank 3, Data Bit 4

Bank 3, Data Bit 5

Bank 3, Data Bit 6

Bank 3, Data Bit 7

U36 or U36 *

U94 or U96 *

U84 or U96 *

U77 or U96 *

U71 or U96 *

U67 or U86 *

U60 or U86 *

U51 or U86 *

U43 or U86 *

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

Replace Memory Chip

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

50yy 201

58yy 201

60yy 201

288 Kbytes

320 Kbytes

352 Kbytes

384 Kbytes

68yy 201

70yy 201

416 Kbytes

448 Kbytes

78yy 201 480 Kbytes

80yy 201 512 Kbytes

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

-----------------------------------------------------------------------------xx00 Parity Bit xx01 xx02 xx04 xx08

Data Bit 0

Data Bit 1

Data Bit 2

Data Bit 3 xx10 xx20

Data Bit 4

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.

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

7

8

9

10

11

4

5

6

2

3

Table 6.1-2.


List: Chassis (Front)

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


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

1 100025-001 ** Handle

100025-001 **

100025-001 **

Handle Bushing

Handle End Cap

101097-001 **

101098-001 **

100025-001 **

Upper Case

Access Panel

Screw, 10-32 x 3/8

T-15 Torx:

101750-001 **

102709-001 *

101099-001 **

101097-001 **

100077-001 **

Chassis Assembly

Brightness knob

Front Bezel

Lower Case

VDU Foot/Detent

12 100031-001 ** Sliding Door Panel

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

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


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

4

5

6

Table 6.1-3.


List: Common Chassis (Front)

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


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

1 105034-001 ** Monitor Assembly

2

3

102709-001 *

100436-002 **

Screw, 4-40 1/4 T-10 Torx

High Voltage Access Plate

100330-001 **

100438-001 **

102709-001 *

Storage Device Access Plate

Board Slots Access Plate

Printed Circuit Board

Retainer

VDU Controller Board 7

8

101340-001 **

100644-001 **

9 100512-001 *** **

Fixed Disk Drive Controller

Board

Fixed Disk Drive Controller

Cables

10

11

100512-001 *** **

101341-001 **

Diskette Drive Controller

Cable

Diskette/Printer Controller

Board

12

13

14

15

101750-001 **

100643-001 **

100437-001 **

101421-001 **

Chassis Assembly

10 Megabyte Fixed Disk Drive

Blank Drive Plate

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 **).


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

Table 6.1-4.


List: Mechanical Chassis (Front)

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


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

1 102709-001 * Printed Circuit Board

Standoff

2

3a ***

100475-001 **

102845-001 **

Power Supply Assembly

Fan/Bracket Assembly

7

8

9

10

5

6

3b

4

100482-001 **

102709-001 *

102709-001 *

100478-001 **

100478-001 **

102709-001 *

101798-001 **

102930-001


Drive Ground Strap

Drive Shock Mount

System Board Assembly

System Board Support Bracket

Screw, 8-32 x 3/8 T-15 Torx

Power Switch Filter Assembly

AC Line Fuse

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

12 100439-001 ** System Board Connector

Access Plate

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



*** For portable computers with serial number 1524020B0001 or above.

For portable computers with serial numbers below 1524020B0001.

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

Table 6.1-5.


List: Monitor Enclosure (Front)

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


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


2

3

100512-001 * **

100493-001 **

VDU Signal Cable

Speaker Assembly

4 100442-002 ** Monitor Floor

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

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


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

6

7

4

5

8

9

2

3

Table 6.1-6: COMPAQ Portable and COMPAQ PLUS Personal Computers Parts

List: System Chassis (Front)

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


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

1 100260-001 Power Cable Harness Assembly

102709-001 *

102709-001 *



100429-001 **

102709-001 *

102709-001 *

102709-001 *

102709-001 *

101750-001 **

Blank, I/O Mounting Bracket

Washer, Internal Tooth

4-40 Hex Nut

Brightness Potentiometer

Drive Shock Mount

System Chassis Assembly

10 102709-001 * Ty-Wrap

11 102709-001 * Push Mount

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



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

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)

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


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

1 101710-001 Assembly, Enclosed Chassis

2 100374-001 ** AC Line Power Cord

3 101790-001 ** Keyboard Assembly

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


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

6

7

4

5

8

9

2

3

Table 6.2-2.


Chassis (Front)

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


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

1 100025-001 ** Handle

100025-001 **

100025-001 **

Handle Bushing

Handle End Cap

101097-001 **

101098-001 **

100025-001 **

101750-001 **

102709-001 *

101763-001 **

Upper Case

Access Panel

Screw, 10-32 x 3/8 T-15 Torx

Chassis Assembly

Brightness Knob

Front Bezel

10

11

101097-001 **

102709-001 *

Lower Case

VDU Foot/Detent

12 100031-001 ** Sliding Door Panel

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



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

6

7

4

5

8

2

3

Table 6.2-3.


Common Chassis (Front) - A

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


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


102709-001 *

100436-002 **


High Voltage Access Plate

9

101747-001 **

101029-003 **

102709-001 *

101340-001 **

102933-001 *** **

102705-001 **

Storage Drive Access Plate

Board Slots Access Plate

PC Board Retainer

VDU Controller Board

Diskette/Tape Controller

Cable

Diskette/Tape Controller

10

11

12

102933-001 *** **

105033-001 **

102933-001 *** **

Board

Fixed Disk Drive

Controller Cables

Memory Expansion Board

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 **).


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

4

5

2

3

Table 6.2-4.


Common Chassis (Front) - B

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


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

1 101750-001 ** Chassis Assembly

102709-001 *

105032-001 **

Fixed Disk Drive LED

Security Lock Assembly

101767-001 **

105032-001 **

Security Lock Bezel

Security Lock Clip

8

9

6

7

101732-001 **

102706-001 **

102709-001 *

102775-001

Blank Drive Plate

20 Megabyte Fixed Disk Drive

Dual Drive Insulator

1.2 Megabyte Diskette Drive

10

11

12

13

102928-001

102779-001 **

101299-001 **

101488-001 **

360 Kbyte Diskette Drive

10 Megabyte Tape Drive

Dual Drive Enclosure

Tape Drive Cartridge

14 102709-001 * Security Lock Switch

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


(PN 102709-001).


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

Table 6.2-5.


Mechanical Chassis (Rear)

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


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

1 102709-001 * Printed Circuit Board Standoff

2 102818-001 ** Power Supply Board Assembly

7

8

9

10

5

6

3

4

101796-001 **

102709-001 *

102709-001 *

101795-001 **

101795-001 **

102709-001 *

102709-001 *

101798-001 **


Drive Ground Strap

Drive Shock Mount

System Board Assembly

System Board Support Bracket



Power Switch Filter Assembly

11

12

102930-001

100439-001 **

AC Line Fuse

System Board Connector

Access Plate

13 102929-001 (replaced by

160272-001) Lithium Battery

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


(PN 102709-001).


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

Table 6.2-6.


Monitor Enclosure (Front)

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


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


2

3

102933-001 * **

100493-001 **

VDU Signal Cable

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 **).


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

6

7

4

5

2

3

Table 6.2-7.


System Chassis (Front)

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


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

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

102709-001 *

100429-001 **


Blank I/O Mounting Bracket

102709-001 *

102709-001 *

102709-001 *

102709-001 *


Washer, Internal Tooth

4-40 Hex Nut

Brightness Potentiometer

8

9

102709-001 *

101750-001 **

Drive Shock Mount

System Chassis Assembly

10 102709-001 * Tie Wrap

11 102709-001 * Push Mount

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


(PN 102709-001).

*** This part is included in the Cable Kit (PN 102933-001 **).


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

Chapter 7. Removal and Replacement Procedures


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.


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


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.


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



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

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



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

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


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


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 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.


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).


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


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.


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).


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.


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.


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



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

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



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

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).

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

CAUTION

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

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.

power

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

bottom of the chassis (Figure 7.12-3).

9.

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

10.

Remove the last two screws that secure the monitor enclosure to the top front of the chassis (Figure 7.12-4)

11.

Disconnect the monitor power signal connector from the monitor sweep board (Figure 7.12-4)

12.

For the COMPAQ Portable and COMPAQ PLUS Personal Computers, disconnect the power cable connector from the sweep board.

13.

To remove the monitor enclosure from the chassis: a.

Carefully slide the monitor enclosure away from the power supply subsystem until the enclosure clears the tab in the back corner of the monitor.

Then slide the enclosure back until the front of the enclosure clears the chassis (Figure 7.12-5).

b.

Lift the monitor enclosure up and out of the chassis and rest one edge on the chassis.

Carefully pull the monitor power cable through the hole in the floor of the monitor assembly.

Lift the monitor enclosure away from the computer and set it aside.

To replace the monitor enclosure, reverse Steps 1 through 13.

Chapter 7.13 Keyboard Assembly Removal and Replacement

To remove the keyboard assembly:

1.

Complete the removal procedure for the system board connector access plate

(see Section 7.7).

2.

Cut the tie wrap that secures the keyboard cable to the chassis and disconnect the keyboard cable from the system board (Figure 7.13-1).

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

CAUTION



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

3.

Position the computer with the keyboard facing you.

Unlock the keyboard and gently pull the keyboard cable out through the front bezel

(Figure 7.13-2).

To replace the keyboard assembly, reverse Steps 1 through 3.

Chapter 7.14 Security Lock Switch Assembly Removal and Replacement

The following procedures are for the COMPAQ PORTABLE 286 Personal Computer

ONLY.

The security lock switch assembly consists of the lock and a lock switch.

To remove the security lock switch assembly:

1.

Complete removal procedures for all installed controller and expansion boards (see Section 7.9).

2.

Disconnect the security lock switch connector from its J117 socket on the system board (Figure 7.14-1).

3.

Remove mass storage device Enclosure B (See Section 7.11).

4.

Unlock the keyboard from the front of the computer.

5.

Locate the security lock switch assembly on the Enclosure B front plate.

6.

Remove the security lock switch assembly by removing the speed clip that secures the assembly in place on the Enclosure B front plate

(Figure 7.14-2).

7.

Cut all tie wraps that secure the switch cable to the chassis.

To replace the security lock switch assembly, reverse Steps 1 through 7.

Chapter 7.15 Battery Removal and Replacement

NOTE: This procedure is to be performed by Authorized COMPAQ Dealers ONLY.

To remove the battery:

1.

Complete the system board removal procedure (see Section 7.10 and

Figure 7.15-1).

2.

Cut the tie wrap that holds the battery in place.

3.

Carefully lift the battery from its velcro mounting and out of the chassis

(Figure 7.15-2).

NOTE: When the battery is disconnected, rerun SETUP when the battery is replaced if CMOS memory has not retained the information entered during SETUP.

To replace the battery, reverse Steps 1 through 3.

Chapter 8. Jumper Settings, Switch Settings, and Adjustments


This section details the switch and jumper settings for the COMPAQ Portable,

COMPAQ PLUS, and COMPAQ PORTABLE 286 Personal Computers.

This section contains external pin assignments for the COMPAQ PORTABLE 286

Diskette/Tape Controller Board and the COMPAQ Asynchronous Communications/

Clock Board.

Also contained in this section are procedures for diskette drive speed adjustment and video display unit adjustments.

When using the tables in this section, remember that the default settings shown are set for the system as configured by COMPAQ.

These settings only need to be changed when the system configuration is changed.

Any time jumpers are changed in a COMPAQ PORTABLE 286 Personal Computer, the

SETUP program must be run on the system to change the system configuration information stored in CMOS memory.

Failure to run SETUP may result in Power

On Self Test errors.

Chapter 8.2 Compaq Portable and Compaq Plus Video Display Controller Board Jumper Settings

There are three versions of the video display controller board.

Determine which version is installed by referencing Figure 8.2-1.

Table 8.2 lists the various combinations of jumper settings for all versions of the COMPAQ video display controller board.

This board supports only those monitors that require positive vertical and positive horizontal synchronization pulses.

For the locations of the video display controller board jumpers, see

Figure 8.2-1.

Table 8-2.

COMPAQ Portable and COMPAQ PLUS Video Display Controller Board

Jumper Settings

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

Jumper

Location Function Pin to Pin 2 Pin 2 to Pin 3

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

J3, J5 Enables/disables RGB and composite video

Disables RGB and composite video

RGB and composite video output always outputs in high resolution output when in high scan (default settings for COMPAQ

Portable, COMPAQ enabled (default setting for

COMPAQ DESKPRO 286)

PLUS and COMPAQ

PORTABLE 286)

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

NOTE: Jumpers J3 and J5 must both be changed at the same time or the video display controller board will malfunction.

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

Chapter 8.3 Compaq Portable 286 Fixed Disk Drive Controller Board Jumper Settings

The COMPAQ PORTABLE 286 fixed disk drive controller board jumpers are set at the factory and should not be changed.

W1 is the fixed disk drive base address select.

It is always set on pin 1 to pin 2.

W2 is the fixed disk drive LED operation.

It is always set on pin 1 to pin 2.

For the locations of the COMPAQ PORTABLE 286 fixed disk drive controller board jumpers, see Figure 8.3-1.

Chapter 8.4 Compaq Portable 286 System Board Jumper Settings

Table 8.4 lists the various combinations of jumper settings for the COMPAQ

PORTABLE 286 board.

For the location of the COMPAQ PORTABLE 286 system board jumpers, see Figure 8.4-1.

If the speed select jumper (ES) is changed to the 6 MHz speed (pin 2 to pin 3), the system will operate only at a 6 MHz clock speed and will not respond to speed change requests from the keyboard when the CTRL + ALT + \ keys are pressed.

If both a monochrome video display controller board (with external monochrome display) and a COMPAQ video display controller board are installed, the monochrome video display will be active during power on if the display select jumper (ED) is set on pin 1 to pin 2.

Table 8.4.

COMPAQ PORTABLE 286 System Board Jumper Settings

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

Jumper


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

ED Display select Monochrome video display controller

COMPAQ dual mode video display controller, non

COMPAQ extended graphics controller, non COMPAQ RGB controllers (default setting)

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

ES Speed select Primary or fast Secondary or common speed (8 MHz) speed (default setting)

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

EM Future Use Do not change Do not change

(default setting)

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

E1 - E3 or "MS"

System Board Memory 128 Kbytes,

256 Kbytes, or

640 Kbytes

512 Kbytes *

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

* For optional 512 Kbyte configuration, PAL (PN 105045-001) must be installed in U2 if not already present.

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

Chapter 8.5 Compaq Portable 286 Diskette/Tape Controller Board Switch and Jumper Settings

Two different versions of the board may be used in the COMPAQ PORTABLE 286 for control of the diskette/tape controller.

Version 1 contains jumpers J1, J2,

J3, and J4; Version 2 contains Switch SW1 and shunt jumpers J1 and J2, which replace jumpers J1 through J4.

Determine which board is installed by referencing Figure 8.5-1 and 8.5-2 before changing the settings.

Table 8.5 lists the various combinations of switch and jumper settings for both versions of the COMPAQ PORTABLE 286 diskette/tape controller board.

For the locations of the COMPAQ PORTABLE 286 diskette/tape controller board jumpers and switch, see Figure 8.5-1.

Table 8.5.

COMPAQ PORTABLE 286 Diskette/Tape Controller Board Jumper and

Switch Settings

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

Jumper


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

J1 Diskette/tape Secondary address Primary address controller board base address select

(370h) (3F0h)

(default setting)

J2 COM1/COM2 select Serial port set to

COM1 (default setting)

Serial port set to

COM2

J3 Printer enabled Parallel printer port Parallel printer port disabled enabled (default setting)

J4 Communications

Interrupt select

Serial Port IRQ4 selected

Serial port IRQ3 selected

(default setting)

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

When changing the asynchronous communications port, both the COM1/COM2 address select (J2) and the IRQ3/IRQ4 interrupt select (J4) must be changed.

If COM 1 is selected, the interrupt IRQ4 must be selected.

If COM2 is selected, the interrupt IRQ3 must be selected.

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

Shunt Jumper

Switch Position Function Switch Setting

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

J1 *

(Shunt Jumper)

Serial communications - open connectors = COM1 on left side IRQ4

- open connectors = COM2 on right side IRQ3

J2 *

(Shunt Jumper)

Controller address select - open connectors on left = primary controller

- open connectors on right = secondary controller

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

* To change the setting, remove the shunt jumper from its socket, rotate it

180 degrees, then reinstall it into the socket.

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

SW1

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

Switch 1 Fixed disk drive enabled - ON = enabled

OFF = disabled

Switch 2 Printer port enabled - ON = enabled

OFF = disabled

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

Switch 3 and Switch 4 Not used

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

Chapter 8.6 Compaq Portable 286 512/2048 KByte Memory Expansion Board Jumper Settings

The total system memory for the COMPAQ PORTABLE 286 Personal Computer can be expanded to the 1.0 to 3.0 megabyte address range by using the 512/2048 Kbyte memory expansion board.

The base memory size depends on the type of RAM chips installed in Bank 1 of

the COMPAQ PORTABLE 286 system board.

64 Kbyte RAM Chips - BASE 256 Kbytes

256 Kbyte RAM Chips - BASE 640 Kbytes or * 512 Kbytes

* For optional 512 Kbyte configuration, a PAL (PN 105045-001) must be installed in U2, if not already present.

Table 8.6 lists the jumper settings and the banks for memory expansion.

Table 8.6.

Memory Expansion Board (1.0 to 3.0 Megabyte Address Range)

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

Jumper Setting E1 - E1 and E5 - E6

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

Banks Installed Resulting Expansion Memory

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

1

1, 2

512 Kbytes

1024 Kbytes

1, 2, 3

1, 2, 3, 4

1536 Kbytes

2048 Kbytes

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

Chapter 8.7 Compaq Portable and Compaq Plus System Jumper Settings

There are two versions of the COMPAQ Portable and COMPAQ PLUS system board.

See Figure 8.7-1 to determine which version you are servicing.

Board Version 1

Bank 0 contains 64 Kbytes of soldered in memory in nine, 64K x 1 RAM chips.

Bank 1 also contains 64 Kbytes of soldered in memory in nine, 64K x 1 RAM chips, for a system total of 128 Kbytes.

Bank 2 consists of nine sockets that can be populated with either 64K x 1 RAM chips or 256K x 1 RAM chips.

Bank 3 also consists of nine sockets that can be populated either with 64K x 1

RAM chips or 256K x 1 RAM chips.

The following chart shows the possible memory configuration on the board:

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

Bank Number Filled With System Total

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

0 64K x 1 RAM

1 64K x 1 RAM 128 Kbytes

Additional Memory Options:

2

2 and 3

64K x 1 RAM

64K x 1 RAM

192 Kbytes

256 Kbytes

2

3

64K x 1 RAM

256K x 1 RAM 448 Kbytes

2 and 3 256K x 1 RAM 640 Kbytes

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

The SW1 and SW2 switch settings on the system and define the configuration for the computer system.

See Figure 8.7-2 for the switch functions and

Tables 8.7-1 and 8.7-2 for the switch position settings.

Table 8.7-1.

SW1 Switch Position Settings

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

Position

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

1 2 3 4 5 6 7 8 Description of Function

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

OFF Not Used

Always OFF (default setting)

ON

OFF OFF

Coprocessor

Always ON (default setting)

Processor Board Memory

Always OFF (default setting)

ON

OFF

OFF

OFF

COMPAQ Video Display

Controller Board

(default setting)

Optional Video

Monochrome Board

ON

OFF

ON

OFF

ON

ON

OFF

OFF

1 Diskette Drive (default)

2 Diskette Drives

3 Diskette Drives

4 Diskette Drives

ON

ON

ON

ON

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

NOTE: Do not use a graphite pencil to change the switch setting.

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

Table 8.7-2.

SW2 Switch Position Settings

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

Position

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

1 2 3 4 5 6 7 8 Description of Function

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

ON OFF ON ON OFF OFF OFF OFF 128 Kbyte Total Memory

ON

OFF

ON

OFF

OFF

OFF

ON

ON

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

192 Kbyte Total Memory




ON

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF



OFF OFF OFF OFF OFF OFF OFF OFF 544 Kbyte Total Memory

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

NOTE: Do not use a graphite pencil to change the switch setting.

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

SW1 tells the system the number of diskette drives available, the type of display to be expected, and whether an 8087 coprocessor is used in the system.

SW2 tells the system the amount of available RAM.

NOTE: If the ROMs installed in socket(s) U40 (and U47 if available) are

Revision C or above, SW2 is ignored.

Therefore, on system boards of

Revision J or above, SW2 has been removed.

If Revision C ROMs or above are installed, 256K x 1 RAM chips may be used instead of 64K x 1 bit RAM chips in banks 2 and 3 of the system board.

To do this, however, a new decoder PROM must be used in socket U35: o PN 101257-001 (No longer available) if banks 2 and 3 are filled with

256K x 1 RAM chips for a total of 640 Kbytes.

o PN 101256-001 if only bank 3 is filled with 256K x 1 RAM chips for a total of 448 Kbytes.

Board Version 2

Bank 0 contains 64 Kbytes of soldered in memory in two, 64K x 4 RAM chips.

Bank 1 also contains 64 Kbytes of soldered in memory in two, 64K x 4 RAM chips, for a system total of 128 Kbytes.

A chip for the parity bit is installed for each bank.

Bank 2 consists of eight sockets that can be populated with either 64K x 1 RAM chips or 256K x 1 RAM chips.

Bank 3 also consists of eight sockets that can be populated either with

64K x 1 RAM chips or 256K x 1 RAM chips.

In addition to Banks 2 and 3, Version 2 also contains Alternate Bank 2 and

Alternate Bank 3.

Sockets in both Alternate Bank 2 and 3 can each be populated with two 64K x 4 RAM chips.

Bank 2 and Alternate Bank 2 use a common chip for the parity bit (U37).

Bank 3 and Alternate Bank 3 also use a common chip for the parity bit (U36).

If Banks 2 and 3 are used, Alternate Banks 2 and 3 are not used.

If Alternate

Banks 2 and 3 are used, Banks 2 and 3 are not used.

Version 2 contains a shunt jumper that is used for selecting either Banks 2 and 3 or Alternate Banks 2 and 3.

The banks are selected as follows:

To enable Banks 2 and 3, insert the shunt jumper so that pins 5-12, 6-11,

7-10, and 8-9 are connected.

To enable Alternate Banks 2 and 3, insert the shunt jumper so that pins 1-16,

2-15, 3-14, and 4-13 are connected.

The banks are selected by removing the shunt jumper, rotating it 180 degrees and reinserting it.

The shunt jumper must be installed for the system board to operate.

The following chart shows the possible memory configuration on the board:

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

Bank Number Filled With System Total

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

0 64K x 4 RAM

1 64K x 4 RAM 128 Kbytes

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

Additional Memory Options:

2 or 3

2 and 3

64K x 1 RAM

64K x 1 RAM

192 Kbytes

256 Kbytes

2

3

64K x 1 RAM

256K x 1 RAM 448 Kbytes

192 Kbytes Alternate 2 or Alternate 3 64K x 4 RAM

Alternate 2 and Alternate 3 64K x 4 RAM 256 Kbytes

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

Banks 2 and 3 and Alternate Banks 2 and 3 require one additional 64K x 1 RAM chip for the parity bit per bank.

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

Because all version 2 boards contain Revision C or higher ROMs, only one switch, SW1, is installed.

Switch SW2 is not installed.

See Table 8.7-1 above.

Chapter 8.8 Compaq Portable and Compaq Plus Asynchronous Communications/Clock Board

Jumper Settings

Jumpers on the COMPAQ Portable and COMPAQ PLUS asynchronous communications/ clock board determine the communications address and the interrupt selection on the board.

Device U13 allows the selection of a 20 mA current loop operation rather than the standard RS-232-C voltage operation.

DO NOT attempt to install two asynchronous communications/clock boards in one system.

If two boards are installed, incorrect operation will result.

For locations of the COMPAQ Portable and COMPAQ PLUS asynchronous communications/clock board jumper settings, see Figure 8.8-1.

See Table 8.8 for jumper setting information for the asynchronous communications/clock board.

Table 8.8.

COMPAQ Portable and COMPAQ PLUS Asynchronous Communications/Clock

Board Jumper Settings

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

Jumper

Location Function Pin 1 to Pin 2 Pin 2 to Pin 3

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

J702 COM1/COM2 select COM2 Address COM1 Address

(default setting)

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

J703 Interrupt select IRQ3 IRQ4 (default setting)

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

U13 Current or voltage Pins 5-12, 6-11, operation

(shunt module)

7-10,8-9:

Serial RS-232-C operation

Pins 1-16, 2-15,

3-14, 4-13:

20 mA current loop operation

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

When changing the COM1/COM2 address of the serial port, both jumpers J702 and

J703 must be changed to correctly select the option desired.

If COM1 is selected, the IRQ4 must be selected.

IF COM2 is selected, the IRQ3 must be selected.

Chapter 8.9 Output Connector Pin

The following tables provide the output connector pin assignments: o Table 8.9-1: 25 pin asynchronous connector o Table 8.9 2: 25 pin parallel connector o Table 8.9-3: 9 pin serial connector

Figure 8.9-1 shows the locations of the output connectors on the COMPAQ

Portable and COMPAQ PLUS Video Display Controller Board.

Figure 8.9-2 shows the location of the output connectors on the COMPAQ

PORTABLE 286 Diskette/Tape Controller Board.

Table 8.9-1.

25 Pin Asynchronous Connector

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

Signal Names and Description Pin Number

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

Protective Ground 1

Transmit Data (TX)

Receive Data (RX)

2

3

Request To Send (RTS)

Clear To Send (CTS)

Data Set Ready (DSR)

Signal Ground (GND)

4

5

6

7

Carrier Detect (CD)

+ Transmit current loop data (20 mA)

+ 5 VDC 200 mA (fuse on board)

- Transmit current loop return (20 mA)

Reverse Channel Option

No Connection

No Connection

No Connection

No Connection

8

9

10

11

12

13

14

15

16

+ Receive current loop data (20 mA)

No Connection

Data Terminal Ready (DTR)

No Connection

17

18

19

20

Ring Indicator (RI)

* EIA ON + 12V Option

21

22

* EIA OFF - 12V Option 23

- Receive current loop return (20 mA) 24

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

* Pins 23 and 24 - No connection on the full height Serial Interface Board.

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

Table 8.9-2.

25 Pin Parallel Connector

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


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

Strobe 1

Data Bit 0

Data Bit 1

2

3

Data Bit 2

Data Bit 3

Data Bit 4

Data Bit 5

4

5

6

7

Data Bit 6

Data Bit 7

Acknowledge

Busy

Paper End

Select

Auto Feed

Error

8

9

10

11

12

13

14

15

Initialize Printer

Select Input

16

17

Signal Ground 18 - 25

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

Table 8.9-3.

9 Pin Serial Connector

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


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

Carrier Detect (CD) 1

Receive Data (RX)

Transmit Data (TX)

2

3

Data Terminal Ready (DTR)

Signal Ground (GND)

Data Set Ready (DSR)

Request To Send (RTS)

4

5

6

7

Clear To Send (CTS) 8

Ring Indicator (RI) 9

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

Chapter 8.10 Diskette Drive Speed Adjustment Procedure

This step by step procedure provides an orderly, easy to follow method of performing any required speed adjustment to the 5 1/4 inch diskette drive(s) contained in the COMPAQ Portable, COMPAQ PLUS, or the COMPAQ PORTABLE 286

Personal Computers.

Read this entire procedure before you begin any work.

After you begin the adjustment procedure, be sure to complete each step before beginning the next one.

To complete the adjustment procedures, you need the following equipment: o All tools required to service COMPAQ Portable, COMPAQ PLUS, and COMPAQ

PORTABLE 286 Personal Computers.

For a listing of these tools, see the

"Foreword" of this guide.

o COMPAQ DIAGNOSTICS Diskette latest version.

o Diskette drive signal extension cable (PN 100546-001).

o Diskette drive power extension cable (PN 100545-001).

Preliminary Steps

1.

Be sure that you have a clean, dry, nonconductive surface on which to work.

2.

Remove the diskette drive you wish to test from the system unit and lay it on its side, next to the computer.

See Chapter 7, "Removal and

Replacement Procedures," for information.

3.

Connect the original power cable on the diskette drive and the diskette

drive controller board to the diskette drive power and signal connectors of the drive being tested (See Chapter 7, "Removal and Replacement

Procedures").

4.

Insert the DIAGNOSTICS diskette into drive A and turn on the system power.

Follow the procedures given in Chapter 4, "Diagnostic Procedures," to bring up the menu similar to the one in Screen 1.

5.

To select the SPEED TEST, type "4" followed by a comma and the drive designator (4, A), then press the ENTER key.

A caution message similar to the following appears:

**** CAUTION ****

DATA WILL BE DESTROYED

INSERT A BLANK FORMATTED DISKETTE IN DRIVE A.

Press the ENTER key when ready

6.

Remove the DIAGNOSTICS diskette from the drive.

Insert a blank, formatted diskette that is not write protected, then press the ENTER key.

NOTE: If you use a scratch diskette that was formatted by DIAGNOSTICS, you cannot use this diskette in an MS-DOS environment until you reformat it using MS-DOS.

If you are testing a COMPAQ PORTABLE 286, the DIAGNOSTICS routine checks the format on the diskette before each test.

You see a prompt similar to:

DISKETTE IN DRIVE IS FORMATTED

FOR 360K (OR 1.2 MEG)

IS THIS THE CORRECT FORMAT (Y/N)

The number of tracks for a 320 Kbyte diskette is 40 and the number of sectors is 8.

For a 360 Kbyte diskette, the number of tracks is 40 and the number of sectors is 9.

For a 1.2 megabyte diskette, the number of tracks is 80 and the number of sectors is 15.

Adjusting the Speed

Each time the index hole of a soft sectored diskette passes the index detector circuitry, this circuitry automatically generates a signal pulse.

As the diskette rotates, the diskette drive speed stabilizes (usually within 5 to

6 seconds), and the speed test program can calculate the time span between these index pulses.

1.

If you followed the preliminary steps to the point of selecting the diskette speed test from the diskette diagnostic menu, you see a message showing the current rotation speed of the diskette drive being tested.

A display similar to the following appears:

THE DISKETTE DRIVE SPEED IS 1667

THE SPEED SHOULD BE IN THE RANGE 1640 TO 1690

PRESS ANY KEY TO EXIT THE TEST

NOTE: The rotational speed value is sometimes displayed in two formats.

Both formats express the same value, but in different terms.

The speed adjustment procedure usually refers to the value in parentheses (that is, the value expressed in ms).

2.

Wait approximately 5 to 6 seconds, or until you see the displayed value stabilize.

Remember that this is a continuously cycling test on a COMPAQ

Portable or COMPAQ PLUS.

The values will continue to scroll up the display.

If you are testing a COMPAQ PORTABLE 286, the speed will not scroll after it has stabilized.

3.

Check the value for diskette rotational speed.

The optimum speed range for the COMPAQ Portable or COMPAQ PLUS Personal Computers 360 Kbyte

Diskette Drive is from 196.0 to 204.0 ms.

The optimum speed range for a

COMPAQ PORTABLE 286 Personal Computer 1.2 Megabyte Diskette Drive is from

164 ms to 170 ms.

4.

If the displayed value is out of the specified parameters, locate the speed adjustment potentiometer on the printed circuit board attached to the diskette drive.

See Chapter 7, "Removal and Replacement

Procedures," for the location of the 360 Kbyte diskette drive and the

1.2 megabyte diskette drive.

5.

Use a small, flat bladed screwdriver and turn the adjustment screw slightly.

If the displayed value is greater than the specified parameters, turn the adjustment screw clockwise; if the displayed value is less than the specified parameters, turn the adjustment screw counterclockwise.

Keep turning the speed adjustment screw in small increments until the speed of the diskette drive is within plus or minus 1 percent of the specified value.

NOTE: The diskette drive(s) in the COMPAQ Portable, COMPAQ PLUS, and the

COMPAQ PORTABLE 286 Personal Computers will operate properly at a speed within plus or minus 2 percent of the specified value.

However, it is good practice to adjust the speed to within plus or minus 1 percent of the specified value.

6.

After you adjust the diskette drive speed, press any key to exit from the test program.

7.

Turn off the system power, remove the diskette drive power and signal extension cables, and reinstall the diskette drive.

Chapter 8.11 Video Display Unit Adjustment Procedure

The video display unit adjustment (also referred to as CRT adjustment) provides the method for performing any required video display adjustment.

To complete the adjustment procedure, the following equipment is required.

o All tools required to service a COMPAQ Portable, COMPAQ PLUS, or COMPAQ

PORTABLE 286 Personal Computer.

For a listing of these tools, see the

"Foreword" of this guide.

o COMPAQ DIAGNOSTICS Diskette latest version.

o Set of standard television adjustment tools.

o Personal Computer Display Template (PN 100686-001 (No longer available)).

Read the entire procedure carefully and completely before starting any work.

Be sure to complete each step before continuing to the next step.

1.

Remove the outer access cover.

See Chapter 7, "Removal and Replacement

Procedures."

2.

Place your computer in a standard working position with the outer access cover removed.

3.

Insert the DIAGNOSTICS diskette in the computer and load the DIAGNOSTICS program.

(See Chapter 4, "DIAGNOSTIC Procedures," for more information on the Advanced Diagnostics program.)

4.

Select the video display alignment procedure from the video display unit test menu and press ENTER.

After you select the video display adjustment procedure, the screen will appear completely blank.

This is normal program operation.

5.

Turn the external BRIGHTNESS knob (located on the front bezel) fully clockwise.

6.

Before making any adjustments, become familiar with Figure 8.11-1, which shows the locations of controls on the high voltage access plate.

7.

Using the label on the high voltage access plate as a guide, locate and adjust the BRITE control until the screen raster appears on the display.

Check this display to make sure it is not tilted in any way.

NOTE: Do not use excessive force when making adjustments on the video display unit.

8.

Turn the BRIGHTNESS control knob until the raster disappears.

9.

Using the VDU alignment procedure contained in the DIAGNOSTICS program, fill the display screen with a character (see Chapter 4, "DIAGNOSTIC

Procedures," for more information on the VDU alignment test screen).

10.

Using a plastic adjustment tool, turn the WIDTH adjustment potentiometer

(pot) until the left and right edges of the display screen fall within the range specified on the adjustment template.

Width may change between high and low resolution mode and should be adjusted for a good compromise.

NOTE: When making adjustments on the video display unit do not use excessive force.

11.

If the characters on your display appear blurry or fuzzy, a focus adjustment is necessary.

Using a plastic adjustment tool, adjust the pot labeled FOCUS until all characters are clear and sharp.

12.

If the characters on your display appear too short or too tall, a character height adjustment is necessary.

Using the VDU adjustment diagnostic program, fill the screen with capital Es.

13.

Two adjustments control the character height.

The first is the MASTER HT control pot, which controls the height of characters in both the high and low resolution text mode.

NOTE: Do not use excessive force when making adjustments on the video

display unit.

14.

Use the CTRL + ALT + < command to place the display in the low resolution graphics mode.

Press and hold down the CTRL and the ALT key and press the less than (<)key.

Then release all three keys.

Using the adjustment tool, adjust the MASTER HT control pot so that all characters appear at the desired height.


15.

Use the CTRL + ALT + > command to place the display in the high resolution mode.

Press and hold down the CTRL key and the ALT key.

Press the greater than (>) key.

Then release all three keys.

Using the adjustment tool, adjust the HI SCAN HT control pot so that all characters appear at the desired height.

16.

If characters on your display appear taller or shorter near the top of the display than those near the bottom, a vertical linearity adjustment is necessary.

Using the VDU adjustment diagnostic, see Chapter 4,

"DIAGNOSTIC Procedures," for more information on the VDU adjustment program.

17.

Using a plastic adjustment tool, turn the VERTICAL LIN control pot until all characters appear equal in height.

NOTE: 1.

This adjustment may affect the character height enough to warrant a readjustment for character height.

2.

If the vertical linearity control does not exist on your video display unit, it is preset and controlled by the video display unit.

3.

Steps 13 and 14 should be repeated after each adjustment until the display is equal.

18.

If your display is shifted to the right or left, a horizontal display centering adjustment is necessary.

Two pots control the centering of the display.

One is the MASTER VID CTR pot, which shifts the display in both a high and low resolution mode.

The other one is the HI SCAN CTR pot, which affects the display in high resolution mode.


19.

Use the CTRL + ALT + < command to place the display in the low resolution graphics mode.

Using the adjustment tool, adjust the MASTER VID CTR pot so that the display is in the center of the screen.

20.

Use the CTRL + ALT + > command to place the display in the high resolution mode.

Using the adjustment tool, adjust the HI SCAN CTR pot so that the display is in the center of the screen.

If your display experiences a problem other than those covered in the previous

20 steps, replace the video display unit.

For video display unit removal and replacement procedures, see Chapter 7,

"Removal and Replacement Procedures."

Compaq COMPAQ PLUS Maintenance And Service Manual

Foreword

Chapter 1. Operating and Performance Specifications

Chapter 1.1 Introduction

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

Chapter 2.1 Introduction

Chapter 2.2 Power On Self Test (POST)

Chapter 2.3 Preliminary Steps to Problem Isolation

Chapter 2.4 Problem Isolation Flowchart

Chapter 3. Setup

Chapter 4. Diagnostic Procedures

Chapter 5. Error Messages and Codes

Chapter 5.1 Introduction

Chapter 5.2 Power On Self Test Error Messages

Chapter 5.3 Diagnostic Error Codes

Chapter 5.4 Memory Error Codes

Chapter 6. Illustrated Parts Catalog

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

Chapter 6.2 Illustrated Parts List for Compaq Portable 286 Personal Computer

Chapter 7. Removal and Replacement Procedures

Chapter 7.1 Introduction

Chapter 7.2 Preparation Procedure

Chapter 7.3 Access Cover Removal and Replacement

Chapter 7.4 Board Slots Access Plate Removal and Replacement

Chapter 7.5 High Voltage Access Plate Removal and Replacement

Chapter 7.6 Mass Storage Device Access Plate Removal and Replacement

Chapter 7.7 System Board Connector Access Plate Removal and Replacement

Chapter 7.8 Power Supply Subsystem Removal and Replacement

Chapter 7.9 Controller and Expansion Board Removal and Replacement

Chapter 7.10 System Board and Memory Option Removal and Replacement

Chapter 7.11 Mass Storage Device Removal and Replacement

Chapter 7.12 Monitor Enclosure Removal and Replacement

Chapter 7.13 Keyboard Assembly Removal and Replacement

Chapter 7.14 Security Lock Switch Assembly Removal and Replacement

Chapter 7.15 Battery Removal and Replacement

Chapter 8. Jumper Settings, Switch Settings, and Adjustments

Chapter 8.1 Introduction

Chapter 8.2 Compaq Portable and Compaq Plus Video Display Controller Board Jumper Settings

Chapter 8.3 Compaq Portable 286 Fixed Disk Drive Controller Board Jumper Settings

Chapter 8.4 Compaq Portable 286 System Board Jumper Settings

Chapter 8.5 Compaq Portable 286 Diskette/Tape Controller Board Switch and Jumper Settings

Chapter 8.6 Compaq Portable 286 512/2048 KByte Memory Expansion Board Jumper Settings

Chapter 8.7 Compaq Portable and Compaq Plus System Jumper Settings

Chapter 8.8 Compaq Portable and Compaq Plus Asynchronous Communications/Clock Board

Jumper Settings

Chapter 8.9 Output Connector Pin

Chapter 8.10 Diskette Drive Speed Adjustment Procedure

Chapter 8.11 Video Display Unit Adjustment Procedure

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