IBM Thinkpad A20mp A21mp A22mp Manual

Intermittent problems
Intermittent system hang problems can be due to a variety
of causes that have nothing to do with a hardware defect,
such as cosmic radiation, electrostatic discharge, or
software errors. FRU replacement should be considered
only when a problem recurs.
When analyzing an intermittent problem, do the following:
1. Run the diagnostic test for the system board in loop
modeat least 10 times.
2. If no error is detected, donotreplace any FRUs.
3. If any error is detected, replace the FRU...

FRU replacement notices
This section contains notices related to removing and
replacing parts. Read this section carefully before replacing
any FRU.
Screw notices
Loose screws can cause a reliability problem. In IBM
ThinkPad computer, this problem is addressed with special
nylon-coated screws that have the following characteristics:
vThey maintain tight connections.
vThey do not easily come loose, even with shock or
vibration.
vThey are harder to tighten.
vThey should be used only once.
Do the following...

vMake sure you use the correct screw. If you have a
torque screwdriver, tighten all screws firmly to the torque
shown in the table.Never use a screw that you
removed. Use a new one. Make sure the screws are
tightened firmly.
Retaining serial numbers
This section includes the following descriptions:
v“Restoring the serial number of the system unit”
v“Retaining the UUID”
Restoring the serial number of the system
unit
When the computer was manufactured, the EEPROM on
the system board was loaded with the...

unique IDs until the year A.D. 3400. No two computers in
the world have the same number.
When you replace the system board, you must set the
UUID on the new system board as follows:
1. Install the ThinkPad hardware maintenance diskette
version 1.62, and restart the computer.
2. From the main menu, select4. Assign UUID.
A new UUID is created and written. If a valid UUID
already exists, it is not overwritten.
FRU replacement notices
58ThinkPad A20m/p, A21m/p, A22m/p 

Removing and replacing a FRU
This section presents directions and drawings for use in
removing and replacing a FRU. Be sure to observe the
following general rules:
1. Do not try to service any computer unless you have
been trained and certified. An untrained person runs
the risk of damaging parts.
2. Before replacing any FRU, review“FRU replacement
notices”on page 56.
3. Begin by removing any FRUs that have to be removed
before the failing FRU. Any such FRUs are listed at the
top of the page. Remove them...

1010 Battery pack
DANGER
Use only the battery in the parts listing for your
computer. Use of an incorrect battery can result in
ignition or explosion of the battery.
Removing and replacing a FRU
60ThinkPad A20m/p, A21m/p, A22m/p 

1020 DIMM
For access, remove this FRU:
v“1010 Battery pack”on page 60
Note:Loosen the screw
1, but do not remove it.
(continued)
Removing and replacing a FRU
ThinkPad A20m/p, A21m/p and A22m/p61 

When installing:With the notched end of the DIMM
toward the socket, insert the DIMM into
the socket, then press it firmly. Pivot the
DIMM until it snaps into place. Make
sure that the card is firmly fixed in the
slot and does not move easily.
Removing and replacing a FRU
62ThinkPad A20m/p, A21m/p, A22m/p 

1030 Mini PCI adapter
For access, remove this FRU:
v“1010 Battery pack”on page 60
Note:Loosen the screw
1, but do not remove it.
21
(continued)
Removing and replacing a FRU
ThinkPad A20m/p, A21m/p and A22m/p63 

For A20m/p, A21m/p series
Note:The illustration shows the combo card. Connector
(A)is for the LAN feature and(B)is for the modem
feature. This slot also supports a Mini PCI modem
card or Mini PCI network card. Step
5depends
on the card type. Disconnect either(A),(B)or both.
When installing the card, do the following:
vWith the notched end of the card toward the socket,
insert the card into the socket, then press it firmly. Pivot
the card until it snaps into place. Make sure that the
card is firmly fixed...