Specifications

ManualsBrandsCompaq ManualsComputer equipmentCompaq Portable II

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.

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.

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.

Summary of content (129 pages)

PAGE 1
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.
PAGE 2
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.
PAGE 3
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 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.
PAGE 4
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.
PAGE 5
o o o Diskette drive signal extension cable (PN 100546-001) Diskette drive power extension cable (PN 100545-001) 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.
PAGE 6
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.
PAGE 7
Power Cable: Length Gauge Environmental Requirements: Temperature: Operating Nonoperating Humidity: Operating Nonoperating 79 in. (2006.6 mm) 18 AWG 50oF to 104oF (10oC to 40oC) 32oF to 140oF (0oC to 60oC) 20% to 80% (noncondensing) 5% to 90% (noncondensing) -----------------------------------------------------------------------------Keyboard Specifications -----------------------------------------------------------------------------Dimensions: Height 1.5 in. (38.1 mm) Depth 7.06 in. (179.3 mm) Width 18.
PAGE 8
-----------------------------------------------------------------------------Dimensions: Height 1.69 in. (4.33 cm) Width 5.875 in. (14.6875 cm) Depth 8.25 in. (20.625 cm) Weight 3.5 lb (1.
PAGE 9
Power Current 4 amps Power Cable: Length 72 in. (1828.
PAGE 10
Average Access Time 105 ms (maximum) Data Transfer Rate 5 Mb/s -----------------------------------------------------------------------------10 Megabyte Tape Drive Specifications -----------------------------------------------------------------------------Dimensions: Height 1.65 in. (4.29 cm) Depth 8 in. (20 cm) Width 5.65 in. (14.76 cm) Weight 1.7 lb (0.765 kg) Media DC 1000 Manufactured by 3M Corporation or equivalent -----------------------------------------------------------------------------1.
PAGE 11
Cooling Current Forced air provided by 16 VDC fan 2 amps, maximum at input voltage of 120 VAC, 60 Hz -----------------------------------------------------------------------------VDC Output: Nominal Current Current Regulation Voltage Amps Amps Tolerance VDC Minimum Maximum * Percent -----------------------------------------------------------------------------+ 5.0 1.5 15.0 2 - 5.0 0.0 0.5 5 + 12.25 1.0 5.0 2 + 12.25 0.0 1.5 3 (internal monitor) - 12.0 0.0 1.
PAGE 12
Chapter 2. Power On Self Tests (POST)/Problem Isolation Chapter 2.1 Introduction This section provides a list of assemblies checked by the Power On Self Test (POST) and a brief description of the types of error codes. The section also contains preliminary steps to problem isolation of an error condition and a problem isolation flowchart for quick reference. Chapter 2.
PAGE 13
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.
PAGE 14
PAGE 15
PAGE 16
PAGE 17
Chapter 3. Setup Please consult the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for current information on SETUP.
PAGE 18
Chapter 4. Diagnostic Procedures Please consult the SUPPORT SOFTWARE MAINTENANCE AND SERVICE GUIDE for current information on DIAGNOSTICS.
PAGE 19
Chapter 5. Error Messages and Codes Chapter 5.1 Introduction This section provides Power On Self Test error messages, DIAGNOSTIC error codes, and memory error codes. The messages and codes are given in tables that list the message or error code, a description of the error, and the probable failure or required action to resolve the error condition. Chapter 5.2 Power On Self Test Error Messages This section is divided into two tables.
PAGE 20
-----------------------------------------------------------------------------304 - Keyboard or System None Keyboard Unit Error -----------------------------------------------------------------------------* See Section 5.4, "Memory Error Codes," for the location of the defective memory chip.
PAGE 21
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.
PAGE 22
102 - 08 287 Coprocessor wrong mask bit set in status register 102 - 15 287 socket is unoccupied, or 287 is inoperative -----------------------------------------------------------------------------Error Error Required Code Description Action -----------------------------------------------------------------------------103 - 01 8237 DMA page registers Replace the system board for error test codes 103 - 01 through 113 - 01.
PAGE 23
109 - 01 CMOS clock load data test failed 109 - 02 CMOS clock rollover test failed 110 - 01 8254 load data test failed 110 - 02 8254 dynamic test failed 111 - 01 Refresh detect test failed 112 - 01 Speed test slow mode out of range 112 - 02 Speed test mixed mode out of range 112 - 03 Speed test fast mode out of range 112 - 04 Speed test unable to enter slow mode 112 - 05 Speed test unable to enter mixed mode 112 - 06 Speed test unable to enter fast mode 112 - 07 Speed test system erro
PAGE 24
203 - 03 Error during restore of program in write/read test 204 - 01 Memory address test failed 204 - 02 Error during saving program memory in address test 204 - 03 Error during restore of program memory address test 205 - 01 Walking I/O test failed 205 - 02 Error during saving program memory in walking I/O test 2. code. Replace the system board.
PAGE 25
303 - 07 Keyboard LED test, LED command test failed 303 - 08 Keyboard LED test, command byte restore test failed 303 - 09 Keyboard LED test, LEDs failed to light 304 - 01 Keyboard typomatic test failed -----------------------------------------------------------------------------315 - 01 Security lock is 1. Replace the security lock.
PAGE 26
402 - 11 Printer interrupt data, and controller register failed 1. 402 - 12 Printer interrupt and loopback failed 2. 402 - 13 Printer interrupt, loopback, and data register failed 3. 402 - 14 Printer interrupt, loopback, and controller register failed 4. 402 - 15 Printer interrupt, loopback, data, and controller register failed 402 - 16 Printer unexpected interrupt received 5. If a printer is connected, be sure it is turned ON and in the online mode.
PAGE 27
-----------------------------------------------------------------------------Error Error Required Code Description Action -----------------------------------------------------------------------------516 - 01 Lightpen text mode test The following steps apply to error failed - no response codes 516 - 01 through 516 - 04: 516 - 0 Lightpen text mode test failed - invalid response 516 - 03 Lightpen medium resolution mode test failed - no response 1. 2. Replace the lightpen. Replace the VDU controller board.
PAGE 28
610 - 03 Previously exceeded max soft error limit 610 - 04 Previously exceeded max hard error limit 3. 4. 610 - 05 Failed to reset controller 610 - 06 Fatal error while reading 610 - 07 Fatal error while writing 5. Replace the diskette drive power and signal cables. Replace the diskette drive assembly. Replace the system board.
PAGE 29
1101 - 02 Serial Port Test, Line input or UART fault 1. 1101 - 03 Serial Port Test, Address line fault 2. 1101 - 04 Serial Port Test, Data line fault 3.
PAGE 30
line failure 1109 - 06 Serial Clock Test, data line failure -----------------------------------------------------------------------------Error Error Required Code Description Action -----------------------------------------------------------------------------Fixed Disk Drive 17yy - xx -----------------------------------------------------------------------------1700 - xx Fixed disk drive ID drive The following steps apply to error test type codes 1700 - xx through 1716 - 59: 1701 - xx Fixed disk drive form
PAGE 31
1716 - 02 Exceeded maximum hard error limit 3. 1716 - 03 Previously exceeded maximum soft error limit 5. 1716 - 04 Previously exceeded maximum hard error limit * 286 based COMPAQ Personal Computers only 1716 - 05 Failed to reset controller 1716 - 06 Fatal error while reading 1716 - 07 Fatal error while writing 4. Replace the fixed disk drive controller board. * Replace the fixed disk drive assembly. Replace the system board.
PAGE 32
1716 - 51 Failed file I/O test in read test The following steps apply to error codes 1700 - xx through 1716 - 59: 1716 - 52 Failed file I/O test in compare test 1. 1716 - 53 Failed drive/head register test 1716 - 54 Failed digital input register test 1716 - 55 Cylinder 1 failed 1716 - 56 Controller RAM failed 1716 - 57 Controller to drive test failed 1716 - 58 Failed to write sector buffer 1716 - 59 Failed to read sector buffer 2. 3. 4. 5.
PAGE 33
1906 - 07 Tape already servo written -----------------------------------------------------------------------------Error Error Required Code Description Action -----------------------------------------------------------------------------Tape Drive 19yy - xx -----------------------------------------------------------------------------1906 - 08 Unable to servo write The following steps apply to all 19yy - xx error codes: 1906 - 09 Unable to format 1. Replace the tape cartridge. 1906 - 10 Format mode error 2.
PAGE 34
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.
PAGE 35
01 U5 U6 U7 U8 02 U20 U21 U22 U23 04 U25 U26 U27 U28 08 U41 U42 U43 U44 10 U47 U48 U49 U50 20 U63 U64 U65 U66 40 U70 U71 U72 U73 80 U81 U82 U83 U84 00 U88 U89 U90 U91 ============================================================================== Table 5.4-2.
PAGE 36
40 U4 U13 U22 U31 U40 U49 U58 U67 20 U5 U14 U23 U32 U41 U50 U59 U68 10 U6 U15 U24 U33 U42 U51 U60 U69 08 U7 U16 U25 U34 U43 U52 U61 U70 04 U8 U17 U26 U35 U44 U53 U62 U71 02 U9 U18 U27 U36 U45 U54 U63 U72 01 U10 U19 U28 U37 U46 U55 U64 U73 00 U11 U20 U29 U38 U47 U56 U65 U74 ============================================================================== COMPAQ Portable and COMPAQ PLUS Memory Error Codes Memory error codes for the COMPAQ Portable a
PAGE 37
1000 201 Bank 1, Parity Bit U38 Replace System Board 1001 201 Bank 1, Data Bit 0 U96 or U69 * Replace System Board 1002 201 Bank 1, Data Bit 1 U86 or U69 * Replace System Board 1004 201 Bank 1, Data Bit 2 U79 or U69 * Replace System Board 1008 201 Bank 1, Data Bit 3 U73 or U69 * Replace System Board -----------------------------------------------------------------------------* Location of Failed Chip if using Alternate Bank 2 and 3.
PAGE 38
-----------------------------------------------------------------------------* Location of Failed Chip if using Alternate Bank 2 and 3. ============================================================================== Table 5.4-5.
PAGE 39
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.
PAGE 40
2 100374-001 ** AC Power Cord 3 100487-001 ** Keyboard Assembly --------------------------------------------------------------------------** Part number no longer available. ============================================================================== Table 6.1-2.
PAGE 41
12 100031-001 ** Sliding Door Panel -----------------------------------------------------------------------------* This part is included in the Miscellaneous Hardware Kit (PN 102709-001). ** Part number no longer available. ============================================================================== Table 6.1-3.
PAGE 42
10 100512-001 *** ** Diskette Drive Controller Cable 11 101341-001 ** Diskette/Printer Controller Board 12 101750-001 ** Chassis Assembly 13 100643-001 ** 10 Megabyte Fixed Disk Drive 14 100437-001 ** Blank Drive Plate 15 101421-001 ** 360 Kbyte Diskette Drive 16 101031-001 ** Diskette Drive Shield (Half Height) -----------------------------------------------------------------------------* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001).
PAGE 43
3b 100482-001 ** Fan/Bracket Assembly 4 102709-001 * Drive Ground Strap 5 102709-001 * Drive Shock Mount 6 100478-001 ** System Board Assembly 7 100478-001 ** System Board Support Bracket 8 102709-001 * Screw, 8-32 x 3/8 T-15 Torx 9 101798-001 ** Power Switch Filter Assembly 10 102930-001 AC Line Fuse 11 102709-001 * Screw, 4-40 x 1/4 T-10 Torx 12 100439-001 ** System Board Connector Access Plate -----------------------------------------------------------------------------* Thes
PAGE 44
2 100512-001 * ** VDU Signal Cable 3 100493-001 ** Speaker Assembly 4 100442-002 ** Monitor Floor -----------------------------------------------------------------------------* This part is contained in the Cable Kit (PN 100512-001 **). ** Part number no longer available. ============================================================================== Table 6.
PAGE 45
10 102709-001 * Ty-Wrap 11 102709-001 * Push Mount -----------------------------------------------------------------------------* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001). ** Part number no longer available. ============================================================================== Chapter 6.2 Illustrated Parts List for Compaq Portable 286 Personal Computer Section 6.
PAGE 46
Item Number Part Number Description -----------------------------------------------------------------------------1 101710-001 Assembly, Enclosed Chassis 2 100374-001 ** AC Line Power Cord 3 101790-001 ** Keyboard Assembly --------------------------------------------------------------------------** Part number no longer available. ============================================================================== Table 6.2-2.
PAGE 47
10 101097-001 ** Lower Case 11 102709-001 * VDU Foot/Detent 12 100031-001 ** Sliding Door Panel -----------------------------------------------------------------------------* These parts are included in the Miscellaneous Hardware Kit (PN 102709-001). ** Part number no longer available. ============================================================================== Table 6.2-3.
PAGE 48
Board 10 102933-001 *** ** Fixed Disk Drive Controller Cables 11 105033-001 ** Memory Expansion Board 12 102933-001 *** ** Mass Storage Power Cable 13 101750-001 ** Chassis Assembly 14 102778-001 Fixed Disk Drive Controller Board -----------------------------------------------------------------------------* These parts are all included in the Miscellaneous Hardware Kit (PN 102709-001). *** These parts are all included in the Cable Kit (PN 102933-001 **). ** Part number no longer available.
PAGE 49
6 101732-001 ** Blank Drive Plate 7 102706-001 ** 20 Megabyte Fixed Disk Drive 8 102709-001 * Dual Drive Insulator 9 102775-001 1.
PAGE 50
3 101796-001 ** Fan/Bracket Assembly 4 102709-001 * Drive Ground Strap 5 102709-001 * Drive Shock Mount 6 101795-001 ** System Board Assembly 7 101795-001 ** System Board Support Bracket 8 102709-001 * Screw, 4-40 1/4 T-10 Torx 9 102709-001 * Screw, 8-32 x 3/8 T-15 Torx 10 101798-001 ** Power Switch Filter Assembly 11 102930-001 AC Line Fuse 12 100439-001 ** System Board Connector Access Plate 13 102929-001 (replaced by 160272-001) Lithium Battery -----------------------------
PAGE 51
-----------------------------------------------------------------------------1 105034-001 ** Monitor Assembly 2 102933-001 * ** VDU Signal Cable 3 100493-001 ** Speaker Assembly 4 100442-002 ** Monitor Floor 5 102933-001 * ** Monitor Power Cable -----------------------------------------------------------------------------* These parts are all included in the Cable Kit (PN 102933-001 **). ** Part number no longer available.
PAGE 52
8 102709-001 * Drive Shock Mount 9 101750-001 ** System Chassis Assembly 10 102709-001 * Tie Wrap 11 102709-001 * Push Mount -----------------------------------------------------------------------------* These parts are all included in the Miscellaneous Hardware Kit (PN 102709-001). *** This part is included in the Cable Kit (PN 102933-001 **). ** Part number no longer available.
PAGE 53
Chapter 7. Removal and Replacement Procedures Chapter 7.1 Introduction Before starting removal procedures, review Chapter 6, "Illustrated Parts Catalog," to become familiar with the various part names and locations. Removal and replacement procedures in this section are written generically for all COMPAQ Portable Computers, except in cases where procedures differ because of design differences.
PAGE 54
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.
PAGE 55
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 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.
PAGE 56
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.
PAGE 57
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 fit securely onto each board board of a different height, board. If the retainers are the bottom side of the board slots access plate installed in your computer.
PAGE 58
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.
PAGE 59
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.
PAGE 60
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.
PAGE 61
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. in until you feel it snap into place. 5. Reconnect all cables removed earlier.
PAGE 62
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.
PAGE 63
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 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).
PAGE 64
To replace the power switch filter assembly, reverse Steps 1 through 5. COMPAQ Portable Power Supply Assembly Removal and Replacement To remove the COMPAQ Portable power supply assembly: 1. Complete the High Voltage Access Plate Removal procedure (see Section 7.5). 2. Remove the power switch filter assembly. 3. Disconnect the remaining fan connector from the power supply assembly (Figure 7.8-7).
PAGE 65
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.
PAGE 66
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).
PAGE 67
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 3. Open the access door panel. 4. Remove the four screws that hold the fan/bracket assembly in place (Figure 7.8-11).
PAGE 68
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.
PAGE 69
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).
PAGE 70
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.
PAGE 71
5. Slide the fuse box back into place. snap into place. Press the cover until you feel it COMPAQ PORTABLE 286 Fan/Bracket Assembly Removal and Replacement To remove the fan/bracket assembly: 1. Complete the High Voltage Access Plate Removal procedure (see Section 7.5). 2. Open the access door panel. 3. Loosen (DO NOT REMOVE) the screw that secures the fan/bracket assembly to the chassis (at the rear of the monitor). 4.
PAGE 72
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 6. Lift the fan/bracket assembly up and out of the computer (Figure 7.8-18).
PAGE 73
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).
PAGE 74
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 3. Using the special two piece socket tool or 5/16 inch box end wrench, loosen the power supply mounting screw from the upper (or lower) right corner of the power supply assembly (Figure 7.8-20). 4.
PAGE 75
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires will make the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< To replace the power supply assembly, reverse Steps 1 through 6.
PAGE 76
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).
PAGE 77
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).
PAGE 78
To remove the fixed disk drive controller board: 1. Complete the Board Slots Access Plate Removal procedure (see Section 7.4). 2. Disconnect the two fixed disk drive controller board signal cables by pulling the connectors away from the board (Figure 7.9-2). >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wire makes the connector grip the pins tighter, which will damage the connector.
PAGE 79
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 fit securely onto each board board of a different height, board. If the retainers are the bottom side of the board slots access plate installed in your computer.
PAGE 80
3. Remove the retaining screw that secures the video display controller board and disconnects the video display signal cable (Figure 7.9-4). NOTE: Controller and expansion board retaining screws may be located either inside or outside the chassis. A tie wrap secures the video display signal cable. Remove this tie wrap before disconnecting the signal cable from the video display controller board.
PAGE 81
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. cable. Pulling on the wires damages the >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 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).
PAGE 82
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.
PAGE 83
Computers) on the system board. (Figure 7.9-7). NOTE: Controller and expansion board retaining screws may be located either inside or outside the chassis. To replace the diskette/tape controller board, reverse Steps 1 through 5. NOTE: Ensure that the retainers on the bottom side of the board slots access plate fit securely onto each board installed in the computer. Also be sure that the board is in the board guide on the left.
PAGE 84
To replace the expansion board, reverse Steps 1 through 4. NOTE: Ensure that the retainers on the bottom side of the board slots access plate fit securely onto each board installed in the computer. If you changed to a board of a different height, rotate the retainers to match the height of the board. Chapter 7.
PAGE 85
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.
PAGE 86
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.
PAGE 87
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.
PAGE 88
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).
PAGE 89
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).
PAGE 90
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: o Enclosure B contains: diskette drive ONLY. 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.
PAGE 91
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 5. Raise the computer as shown in Figure 7.11-3.
PAGE 92
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.
PAGE 93
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.
PAGE 94
4. Disconnect any power cables that may be connected to sockets J114 or J115 on the system board (Figure 7.11-6) of a COMPAQ PORTABLE 286 Personal Computer. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 5. Raise the computer as shown in Figure 7.
PAGE 95
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 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.
PAGE 96
8. Slide Enclosure A to the rear of the computer and lift it up and out of the computer (Figure 7.11-9).
PAGE 97
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. Device 1A.
PAGE 98
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).
PAGE 99
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.
PAGE 100
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.
PAGE 101
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.
PAGE 102
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.
PAGE 103
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< CAUTION Pull only on the connector, do not pry. Pulling on the wires makes the connector grip the pins tighter, which will damage the connector. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 3. 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).
PAGE 104
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.
PAGE 105
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).
PAGE 106
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.
PAGE 107
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.
PAGE 108
Chapter 8. Jumper Settings, Switch Settings, and Adjustments Chapter 8.1 Introduction 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.
PAGE 109
PAGE 110
Table 8-2.
PAGE 111
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.
PAGE 112
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.
PAGE 113
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.
PAGE 114
-----------------------------------------------------------------------------J1 Diskette/tape Secondary address Primary address controller board (370h) (3F0h) base address select (default setting) J2 COM1/COM2 select Serial port set to COM1 (default setting) Serial port set to COM2 J3 Printer enabled Parallel printer port disabled Parallel printer port enabled (default setting) J4 Communications Interrupt select Serial Port IRQ4 Serial port IRQ3 selected selected (default setting) ----------------
PAGE 115
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.
PAGE 116
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.
PAGE 117
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.
PAGE 118
-----------------------------------------------------------------------------NOTE: Do not use a graphite pencil to change the switch setting. ============================================================================== Table 8.7-2.
PAGE 119
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 Alternate Bank 3. Sockets populated with two 64K x 4 common chip for the parity common chip for the parity 3, Version 2 also contains Alternate Bank 2 and in both Alternate Bank 2 and 3 can each be RAM chips. Bank 2 and Alternate Bank 2 use a bit (U37). Bank 3 and Alternate Bank 3 also use a bit (U36). If Banks 2 and 3 are used, Alternate Banks 2 and 3 are not used.
PAGE 120
Chapter 8.8 Compaq Portable and Compaq Plus Asynchronous Communications/Clock Board Jumper Settings Jumpers on the COMPAQ clock board determine on the board. Device operation rather than Portable and COMPAQ PLUS asynchronous communications/ the communications address and the interrupt selection U13 allows the selection of a 20 mA current loop the standard RS-232-C voltage operation. DO NOT attempt to install two asynchronous communications/clock boards in one system.
PAGE 121
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 o o Table 8.9-1: Table 8.9 2: Table 8.
PAGE 122
Table 8.9-1.
PAGE 123
+ Receive current loop data (20 mA) 17 No Connection 18 Data Terminal Ready (DTR) 19 No Connection 20 Ring Indicator (RI) 21 * EIA ON + 12V Option 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.
PAGE 124
Table 8.9-3.
PAGE 125
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.
PAGE 126
IS THIS THE CORRECT FORMAT The number is 8. For sectors is the number (Y/N) of tracks for a 320 Kbyte diskette is 40 and the number of sectors a 360 Kbyte diskette, the number of tracks is 40 and the number of 9. For a 1.2 megabyte diskette, the number of tracks is 80 and 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.
PAGE 127
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.
PAGE 128
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.
PAGE 129
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. NOTE: Do not use excessive force when making adjustments on the video display unit. 15. Use the CTRL + ALT + > command to place the display in the high resolution mode.