IBM ThinkPad 600, Hardware Maintenance Manual, Page: 44 / 124

Checkout Guide
4. If the voltage is still less than
+
11.0 V dc after
recharging, replace the battery.
5. If the voltage is more than
+
11.0 V dc, measure the
resistance between battery terminals 3 and 4. The
resistance must be 4 to 30 K ohm.
6. If the resistance is not correct, replace the battery
pack. If the resistance is correct, replace the system
board.
Checking the Backup Battery:
Do the following:
1. Power off the computer and unplug the AC Adapter
from the computer.
2. Turn the computer upside down.
3. Remove the backup battery (see “Removal and
Replacement” section of each model).
4. Measure the voltage of the backup battery. See the
following figure.
Note
Be careful not to measure the wrong side of the
backup battery.
Ÿ
If the voltage is correct, replace the system board.
Ÿ
If the voltage is not correct, replace the backup
battery.
Ÿ
If the backup battery discharges quickly after
replacement, replace the system board.
Wire Voltage (V dc)
Red
+
2.5 to
+
3.2
Black Ground
System Board and CPU Card Checkout
The processing functions are performed by both the
system board and the CPU card. Processor problems can
be caused by either FRU. However, the CPU card
generally has a lower probability of failure. If a numeric
code indicates the system board or the CPU card as a
failing FRU, or the CPU card is indicated by a diagnostic
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