IBM PS/2 N51 SX HMR Owner's manual

FRONT
PICTURE 1
October 22, 1991
This pamphlet contains procedures for isolating problems to a FRU, a
Symptom-to-FRU Index, and a parts listing for the IBM Personal System/2
Model N51 SX.
This pamphlet is intended to be used with the IBM Personal System/2
Hardware Maintenance Reference manual (part number 15F2190, form number
S15F-2190-00) and the IBM Personal System/2 Hardware Maintenance Service
manual (part number 15F2200, form number S15F-2200-00).
Part Number 04G5112
Form Number S04G-5112-00
IBM PS/2 Model N51 SX HMS
¦ Copyright IBM Corp. 1991
FRONT - 1

FRONT_1 Safety Information
Refer to the Hardware Maintenance Service General Information pamphlet for
the following information:
General Safety
Electrical Safety
Safety Inspection Guide.
First Edition (October 1991)
The following paragraph does not apply to the United Kingdom or any
country where such provisions are inconsistent with local law:
INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION "AS
IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. Some states do not allow disclaimer or express
or implied warranties in certain transactions, therefore, this statement
may not apply to you.
This publication could include technical inaccuracies or typographical
errors. Changes are periodically made to the information herein; these
changes will be incorporated in new editions of the publication. IBM may
make improvements and/or changes in the product(s) and/or the program(s)
described in this publication at any time.
It is possible that this publication may contain reference to, or
information about, IBM products (machines and programs), programming, or
services that are not announced in your country. Such references or
information must not be construed to mean that IBM intends to announce
such IBM products, programming, or services in your country.
Requests for technical information about IBM products should be made to
your IBM Authorized Dealer or your IBM Marketing Representative.
IBM may have patents or pending patent applications covering subject
matter in this document. The furnishing of this document does not give
you any license to these patents. You can send license inquiries, in
writing, to the IBM Director of Commercial Relations, IBM Corporation,
Armonk, NY 10577.
¦ Copyright International Business Machines Corporation 1991. All rights
reserved.
Note to U.S. Government Users -- Documentation related to restricted
rights -- Use, duplication or disclosure is subject to restrictions set
forth in GSA ADP Schedule Contract with IBM Corp.
IBM PS/2 Model N51 SX HMS
Safety Information
¦ Copyright IBM Corp. 1991
FRONT_1 - 1

FRONT_2 Notices
References in this publication to IBM products, programs, or services do
not imply that IBM intends to make these available in all countries in
which IBM operates. Any reference to an IBM product, program or service
is not intended to state or imply that only IBM's product, program, or
service may be used. Any functionally equivalent product, program, or
service that does not infringe any of IBM's intellectual property rights
or other legally protectible rights may be used instead of the IBM
product, program, or service. Evaluation and verification of operation in
conjunction with other products, programs, or services, except those
expressly designated by IBM, are the user's responsibility.
IBM may have patents or pending patent applications covering subject
matter in this document. The furnishing of this document does not give
you any license to these patents. You can send license inquiries, in
writing, to the IBM Director of Commercial Relations, IBM Corporation,
Purchase, NY 10577.
Subtopics
FRONT_2.1 Trademarks and Service Marks
IBM PS/2 Model N51 SX HMS
Notices
¦ Copyright IBM Corp. 1991
FRONT_2 - 1

FRONT_2.1 Trademarks and Service Marks
The following terms, denoted by an asterisk (*) in this publication, are
trademarks of the IBM Corporation in the United States and/or other
countries:
IBM
Personal System/2.
IBM PS/2 Model N51 SX HMS
Trademarks and Service Marks
¦ Copyright IBM Corp. 1991
FRONT_2.1 - 1

CONTENTS Table of Contents
FRONT_1 Safety Information
FRONT_2 Notices
FRONT_2.1 Trademarks and Service Marks
CONTENTS Table of Contents
1.0 General Checkout
1.1 How to Diagnose Combined FRUs
1.2 How to Use Error Messages
1.3 How to Disable the Power-On Password
2.0 Installed Devices List
3.0 Undetermined Problem
4.0 Hard Disk Partition
4.1 Restoring the Partition
4.2 Setting System Configuration
5.0 Power Supply
5.1 Checking the AC Adapter
5.2 Checking the Car Battery Adapter
5.3 Checking the Battery Pack
5.4 Checking the Backup Battery
5.5 Checking the Standby Battery
5.6 Checking the Quick Charger
5.7 Checking the Voltage Converter
6.0 Keyboard
7.0 Printer
8.0 External Display Self-Test
9.0 Memory
10.0 Symptom-to-FRU Index
10.1 No-Beep Symptoms
10.2 Beep Symptoms
10.3 Miscellaneous Symptoms
10.4 Numeric Error Codes
11.0 How To Use This Parts Catalog
12.0 System Overview
13.0 Parts
IBM PS/2 Model N51 SX HMS
Table of Contents
¦ Copyright IBM Corp. 1991
CONTENTS - 1

1.0 General Checkout
The diagnostic tests are intended to test only IBM (*) products. Non-IBM
products, prototype cards, or modified options can give false errors and
invalid system responses.
Warning: Drives in the system you are servicing might have been rearranged
or the drive startup sequence might have been altered. Be extremely
careful during write operations such as copying, saving, or formatting.
Data or programs can be overwritten if you select an incorrect drive.
(*) IBM is a trademark of the International Business Machines
Corporation.
Subtopics
1.1 How to Diagnose Combined FRUs
1.2 How to Use Error Messages
1.3 How to Disable the Power-On Password
IBM PS/2 Model N51 SX HMS
General Checkout
¦ Copyright IBM Corp. 1991
1.0 - 1

1.1 How to Diagnose Combined FRUs
If an adapter or device consists of more than one FRU, an error code can
be caused by any of the FRUs. Before replacing the adapter or device,
remove the FRUs, one by one, to see if the symptoms change.
IBM PS/2 Model N51 SX HMS
How to Diagnose Combined FRUs
¦ Copyright IBM Corp. 1991
1.1 - 1

1.2 How to Use Error Messages
Use the error codes displayed on the screen to diagnose failures. If more
than one error code is displayed, begin the diagnosis with the first error
code. The cause of the first error code can result in false error codes
being displayed. If no error code is displayed, see if the error symptom
is listed in the "Symptom-to-FRU Index" in topic 10.0.
IBM PS/2 Model N51 SX HMS
How to Use Error Messages
¦ Copyright IBM Corp. 1991
1.2 - 1

1.3 How to Disable the Power-On Password
To disable the power-on password, do the following:
1. Power-off the system.
2. Remove the battery pack and the bottom cover.
3. Identify the password-override connector on the system board.
4. Install a jumper over the pins at position 1.
5. Power-on the system and leave it until the POST ends.
Make sure that you remove the jumper from the password-override connector
when you are finished.
To reactivate the password, start the system programs, select Set features
from the Main Menu, then select Set password and unattended start mode,
and follow the instructions on the screen.
+---+
¦001¦
+---+
DOES THE PROBLEM APPEAR TO BE A POWER SUPPLY FAILURE?
Yes No
¦ ¦
¦ +---+
¦ ¦002¦
¦ +---+
¦ Go to Step 006.
¦
+---+
¦003¦
+---+
DO ALL SYSTEM-STATUS INDICATORS REMAIN OFF?
Yes No
¦ ¦
¦ +---+
¦ ¦004¦
¦ +---+
¦ Go to Step 006.
¦
+---+
¦005¦
+---+
Go to "Power Supply" in topic 5.0.
--------------------------------------------------------------------------
+---+
¦006¦
+---+
- Power-off the system and all external devices.
- Check all cables and power cords.
- Make sure no diskette is in the drive.
- Power-on all external devices.
- Power-on the system and check for the following responses:
1. All system-status indicators appear once for about 1 second.
Note: Some indicators remain on and others go off after 1 second.
2. Memory test (the number increases.)
3. One or two short beeps.
DID YOU RECEIVE THE RESPONSES LISTED ABOVE?
Yes No
¦ ¦
¦ +---+
¦ ¦007¦
¦ +---+
¦ 1. If the memory count is incorrect, go to "Memory" in topic 9.0.
¦ 2. Go to "Symptom-to-FRU Index" in topic 10.0.
¦ If that does not correct the problem, go to"Undetermined Problem"
¦ in topic 3.0 .
¦
¦
+---+
¦008¦
+---+
- Press Ctrl+Alt+Delete. When the cursor moves to the upper right, press
Ctrl+Alt+Insert to start the system program. If the IBM logo screen
does not appear, insert the backup Reference Diskette into the diskette
drive and repeat this step.
1. If you are not at the Main Menu, follow the instructions on the
screen to advance to the Main Menu.
If you cannot advance to the Main Menu, go to "Symptom-to-FRU Index"
in topic 10.0.
- or -
If that does not correct the problem, go to"Undetermined Problem" in
IBM PS/2 Model N51 SX HMS
How to Disable the Power-On Password
¦ Copyright IBM Corp. 1991
1.3 - 1

topic 3.0 .
Notes:
a. If the system has an incorrect keyboard or numeric keypad
response, go to "Keyboard" in topic 6.0.
b. If the printer has incorrect responses, go to "Printer" in
topic 7.0.
c. If the external CRT display has problems such as jittering,
rolling, shifting, or being out-of-focus, go to "External
Display Self-Test" in topic 8.0.
2. Press Ctrl+A and run the system checkout.
IS THE LIST OF INSTALLED DEVICES CORRECT?
Yes No
¦ ¦
¦ +---+
¦ ¦009¦
¦ +---+
¦ Go to "Installed Devices List" in topic 2.0.
¦
+---+
¦010¦
+---+
- Run the diagnostic tests.
DID THE TEST IDENTIFY A FAILURE?
Note: If the test stops and you cannot continue, replace the last device
tested.
- or -
If any POST error code appears, go to"Symptom-to-FRU Index" in
topic 10.0 .
Yes No
¦ ¦
¦ +---+
¦ ¦011¦
¦ +---+
¦ You may have an intermittent problem:
¦ Check for damaged cables and connectors.
¦ Reseat all adapters, drives, and modules.
¦ Start an error log and run the tests multiple times.
¦ Check the power supply in use when the error is reported (see
¦ "Power Supply" in topic 5.0).
¦ Check "Symptom-to-FRU Index" in topic 10.0. If this does not fix
¦ the problem, go to "Undetermined Problem" in topic 3.0.
¦
+---+
¦012¦
+---+
Go to "Symptom-to-FRU Index" in topic 10.0.
--------------------------------------------------------------------------
IBM PS/2 Model N51 SX HMS
How to Disable the Power-On Password
¦ Copyright IBM Corp. 1991
1.3 - 2

2.0 Installed Devices List
The Installed Devices List shows the presence of devices on the system.
If an adapter or device is missing from the list, you may have one of the
following conditions.
Warning: A customized setup configuration (other than default settings)
might exist on the system you are servicing. Running Automatic
Configuration can alter those settings. Note the current configuration
settings (using the 1. View configuration) and verify that the same
settings are in place when service is complete. (For more information
about configuration, refer to the Hardware Maintenance Reference manual.)
The protected partition on the hard disk or the Reference Diskette you
are using does not contain the code required to support that device.
An adapter or device is defective.
The device missing from the list is an unrecognizable drive or
adapter.
The device missing from the list requires an additional diskette.
(See the service manual.)
A power supply voltage is incorrect (see "Power Supply" in topic 5.0).
If the adapter is on the list, run the adapter diagnostics tests. If the
list contains an adapter or device that is not installed, go to
"Undetermined Problem" in topic 3.0.
IBM PS/2 Model N51 SX HMS
Installed Devices List
¦ Copyright IBM Corp. 1991
2.0 - 1

3.0 Undetermined Problem
You are here because the diagnostics tests did not identify the failing
FRU.
Check the power supply in use (see "Power Supply" in topic 5.0). If the
power supply is operating correctly, return here and continue with the
following procedure.
1. Power-off the system.
2. Remove or disconnect one of the following devices or adapter: ( Do not
isolate FRUs that are known to be good.)
a. Non-IBM devices
b. Modem, printer, mouse, or other external device
c. Memory module kit
d. Hard disk drive (fixed disk drive)
e. Communications cartridge
f. Any adapter and device.
3. Power-on the system and start the system program.
4. Press Ctrl+A to run the system checkout. Do not configure the system.
If diagnostics cannot be loaded from the hard disk, try and load them
from the Reference Diskette. Test only those adapters and devices
still attached to the system.
5. If the symptom remains, repeat steps 1 through 3 until you find the
failing FRU or until all FRUs have been removed.
6. If all of the FRUs listed have been removed and the problem remains,
replace the system board.
IBM PS/2 Model N51 SX HMS
Undetermined Problem
¦ Copyright IBM Corp. 1991
3.0 - 1

4.0 Hard Disk Partition
A protected partition on the hard disk contains the system configuration
data set, system setup programs, and customer and advanced diagnostics.
System setup and diagnostic programs can be loaded from this partition by
pressing and holding Ctrl+Alt+Delete and, as soon as the cursor moves to
the upper right corner of the display, pressing and holding
Ctrl+Alt+Insert.
Subtopics
4.1 Restoring the Partition
4.2 Setting System Configuration
IBM PS/2 Model N51 SX HMS
Hard Disk Partition
¦ Copyright IBM Corp. 1991
4.0 - 1

4.1 Restoring the Partition
If a system or hard disk problem prevents system setup or diagnostic
programs from being loaded from the protected partition, load and run the
programs from the Reference Diskette. If no errors are found, restore the
programs to the protected partition on the hard disk using the following
procedure.
1. Start the system with the customer's backup copy of the Reference
Diskette installed.
Note: The languages of the Reference Diskette and the system must
match.
2. Select the 2. Backup/Restore system programs from the Main Menu.
3. Select the 3. Restore the system partition option to load the system
setup and utility programs, and the customer and advanced diagnostic
programs onto the system partition of the hard disk.
If this does not correct the problem, use the backup copy of the Reference
Diskette to format the hard disk and then restore the programs to the
protected partition. If the problem remains, return to the I998XXXX,
I9990303 error code (on page 10.4 in the Symptom-to-FRU index).
Note: After the programs have been restored, the Insert-Diskette icon
appears, unless an operating system is present.
IBM PS/2 Model N51 SX HMS
Restoring the Partition
¦ Copyright IBM Corp. 1991
4.1 - 1

4.2 Setting System Configuration
If you configure the system using the 4. Set configuration from the
Reference Diskette, make sure the languages of the Reference Diskette and
the system must match.
IBM PS/2 Model N51 SX HMS
Setting System Configuration
¦ Copyright IBM Corp. 1991
4.2 - 1

5.0 Power Supply
As the battery pack, backup and standby batteries have a given lifespan,
having spares of these batteries on hand can eliminate problems. When one
of these batteries is suspected of failing, the spare can be used in its
place. One or all of these batteries can be discharged if a short circuit
is present in the system.
1. Replace the failing FRU if the power supply problem is caused by a
short circuit.
2. Determine if one (or all) of the batteries have become discharged.
Replace any discharged battery with its spare.
The test procedures for each power device are found on the following
pages.
"Checking the AC Adapter" in topic 5.1.
"Checking the Car Battery Adapter" in topic 5.2.
"Checking the Battery Pack" in topic 5.3.
"Checking the Backup Battery" in topic 5.4.
"Checking the Standby Battery" in topic 5.5.
"Checking the Quick Charger" in topic 5.6.
None of the above. Follow the steps below.
+---+
¦001¦
+---+
DID THE PROBLEM OCCUR ONLY WHEN USING THE AC ADAPTER?
Yes No
¦ ¦
¦ +---+
¦ ¦002¦
¦ +---+
¦ Go to Step 004.
¦
+---+
¦003¦
+---+
Go to "Checking the AC Adapter" in topic 5.1.
If"Checking the AC Adapter" does not correct the problem, replace the
voltage converter.
--------------------------------------------------------------------------
+---+
¦004¦
+---+
DID THE PROBLEM OCCUR ONLY WHEN USING THE CAR BATTERY ADAPTER?
Yes No
¦ ¦
¦ +---+
¦ ¦005¦
¦ +---+
¦ Go to Step 007.
¦
+---+
¦006¦
+---+
Go to "Checking the Car Battery Adapter" in topic 5.2.
--------------------------------------------------------------------------
+---+
¦007¦
+---+
DID THE PROBLEM OCCUR ONLY WHEN USING THE BATTERY?
Yes No
¦ ¦
¦ +---+
¦ ¦008¦
¦ +---+
¦ Go to Step 014.
¦
+---+
¦009¦
+---+
DOES A FULLY-CHARGED BATTERY DISCHARGE QUICKLY?
Yes No
¦ ¦
¦ +---+
¦ ¦010¦
¦ +---+
¦ Go to Step 013.
¦
IBM PS/2 Model N51 SX HMS
Power Supply
¦ Copyright IBM Corp. 1991
5.0 - 1

+---+
¦011¦
+---+
- Run advanced diagnostics for all devices using the AC adapter. Use the
'RUN TEST ONE TIME' option.
DID ALL THE TESTS END WITHOUT AN ERROR?
Yes No
¦ ¦
¦ +---+
¦ ¦012¦
¦ +---+
¦ Follow the instructions on the screen.
¦ If the instructions do not appear or do not correct the problem,
¦ replace the system board.
¦
¦
+---+
¦013¦
+---+
Go to "Checking the Battery Pack" in topic 5.3.
If "Checking the Battery Pack" does not correct the problem, go to
"Checking the Voltage Converter" in topic 5.7.
--------------------------------------------------------------------------
+---+
¦014¦
+---+
- Unplug the AC adapter if used.
- Remove the bottom cover and disconnect the flat cable from connector CN6
on the voltage converter. (See page 5.7 for the connector location.)
- Check that the resistance at connector CN5 is greater than 5 ohms
between pins 7 and 1, and also between 7 and 3.
IS THE RESISTANCE CORRECT?
Yes No
¦ ¦
¦ +---+
¦ ¦015¦
¦ +---+
¦ Go to Step 017.
¦
+---+
¦016¦
+---+
Go to "Checking the Voltage Converter" in topic 5.7.
If"Checking the Voltage Converter" does not correct the problem, go to
Step 017.
--------------------------------------------------------------------------
+---+
¦017¦
+---+
- Remove the following if installed:
Battery pack
Standby battery
Backup battery
Memory module kit
Internal Data/Fax modem
Serial adapter
Numeric keypad
Mouse
External display
Hard disk drive
Diskette drive
LCD inverter cable
LCD panel cable.
- Make sure the voltage converter is correctly installed.
- Plug in the AC adapter and power-on the system.
DID YOU HEAR ONE LONG OR TWO SHORT BEEPS?
Yes No
¦ ¦
¦ +---+
¦ ¦018¦
¦ +---+
¦
¦ Replace the following FRUs one at a time until the problem is
¦ corrected.
¦ Voltage converter
¦ I/O panel assembly
¦ System board.
¦
+---+
¦019¦
+---+
IBM PS/2 Model N51 SX HMS
Power Supply
¦ Copyright IBM Corp. 1991
5.0 - 2

Replace the voltage converter to verify the fix. If the problem still
remains, do the following.
- Suspect one of the options or devices. Reinstall each of the options or
devices to the system one at a time, and power-on the system to see if
the original problem occurs.
- Replace the last installed option or device when the problem occurs.
--------------------------------------------------------------------------
Subtopics
5.1 Checking the AC Adapter
5.2 Checking the Car Battery Adapter
5.3 Checking the Battery Pack
5.4 Checking the Backup Battery
5.5 Checking the Standby Battery
5.6 Checking the Quick Charger
5.7 Checking the Voltage Converter
IBM PS/2 Model N51 SX HMS
Power Supply
¦ Copyright IBM Corp. 1991
5.0 - 3

5.1 Checking the AC Adapter
If the Power-On indicator is not on, check the power cord of the AC
adapter for proper installation and continuity.
1. If any noise can be heard from the AC adapter when it is plugged into
line voltage, replace the AC adapter with a new one.
If no noise can be heard from the adapter, go to Step 3.
2. If the noise still comes from the new AC adapter, suspect the system
unit. Replace the AC adapter with the original one, then go to the
next step. If no noise comes from the new adapter, the original
adapter has the problem.
3. Unplug the AC adapter cable from the system and measure the output
voltage at the plug of the AC adapter cable.
PICTURE 2
+------------------------------------------------------------------------+
¦ Pin ¦ Voltage (V dc) ¦
+------------------------------------+-----------------------------------¦
¦ 1 ¦ +19.0 to +21.0 ¦
+------------------------------------+-----------------------------------¦
¦ 2 ¦ Ground ¦
+------------------------------------------------------------------------+
If the voltage is not correct:
1. Unplug the AC adapter from the ac power outlet and leave it for a
few minutes.
2. Plug the AC adapter into the ac outlet.
3. Measure the output voltage of the AC adapter.
4. If the voltage is still not correct, replace the AC adapter.
If the voltage is OK, plug the cable into the system and try the
failing operation again.
If the problem still remains, replace the voltage converter. If the
problem disappeared, suspect the installation and continuity of the AC
adapter cable.
IBM PS/2 Model N51 SX HMS
Checking the AC Adapter
¦ Copyright IBM Corp. 1991
5.1 - 1

5.2 Checking the Car Battery Adapter
If an output voltage from a cigarette lighter socket is less than 10.5 V
dc, the power-on indicator on the car battery adapter blinks and a noise
can be heard continuously. The battery of the car is defective.
1. Unplug the car battery adapter from the computer if connected.
2. Plug the car battery adapter into the cigarette lighter socket.
Note: If the adapter is already plugged in, be sure to unplug the
adapter from the cigarette lighter socket, then plug it into
the socket again.
3. Measure the output voltage of the car battery adapter.
PICTURE 3
+------------------------------------------------------------------------+
¦ Pin ¦ Voltage (V dc) ¦
+------------------------------------+-----------------------------------¦
¦ 1 ¦ +19.0 to +21.0 ¦
+------------------------------------+-----------------------------------¦
¦ 2 ¦ Ground ¦
+------------------------------------------------------------------------+
If the voltage is correct and the power-on indicator on the car
battery adapter is on steady, the car battery adapter is working
correctly.
If the voltage is out of range, do one of the following.
Try the above test procedures on another car if available.
Replace the car battery adapter if the system works with the AC
adapter and does not work with the car battery adapter.
IBM PS/2 Model N51 SX HMS
Checking the Car Battery Adapter
¦ Copyright IBM Corp. 1991
5.2 - 1