IBM R50 Series Hardware Maintenance Manual page 120

Removing and replacing a FRU
Important
When handling the system board, bear the following
in mind.
v The system board of the ThinkPad R50/R50p,
and R51 series has an accelerometer, which can
be broken by applying several thousands of
G-forces.
Note: Dropping a system board from a height of
v Be careful not to drop the system board on a
bench top that has a hard surface, such as metal,
wood, or composite.
v If a system board is dropped, you must test it,
using PC-Doctor DOS, to make sure that the IBM
HDD Active Protection still functions (see below).
Note: If the test shows that IBM HDD Active
v Avoid rough handling of any kind.
v At every point in the process, be sure not to drop
or stack the system board.
v If you put a system board down, be sure to put it
only on a padded surface such as an ESD mat or
conductive corrugated material.
After replacing the system board, run PC-Doctor
DOS to make sure that IBM HDD Active Protection
still functions. The procedure is as follows:
1. Place the computer on a horizontal surface.
2. Run Diagnostics --> Other Devices --> IBM
HDD Active Protection Test.
Attention:
computer while the test is running.
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R50/R50p, R51 Series
as little as 6 inches so that it falls flat on a
hard bench can subject the accelerometer
to as much as 6,000 G's of shock.
Protection is not functioning, be sure to
document the drop in any reject report,
and replace the system board.
Do not apply physical shock to the