IBM PS/2 N51 SX Hardware Maintenance Service page 22

5.4 Checking the Backup Battery
1. Invert the system unit and place it on its top.
2. Remove the bottom cover.
3. Disconnect the battery connector from the voltage converter.
4. Measure the voltage of the backup battery.
PICTURE 6
+------------------------------------------------------------------------+
¦ Wire
+------------------------------------+-----------------------------------¦
¦ Red
+------------------------------------+-----------------------------------¦
¦ Black
+------------------------------------------------------------------------+
If the voltage is correct, replace the system board.
backup battery is discharged by a short circuit or is defective.
IBM PS/2 Model N51 SX HMS
Checking the Backup Battery
¦ Voltage (V dc)
¦ +2.5 to +3.7
¦ Ground
If it is not, the
¦ Copyright IBM Corp. 1991
5.4 - 1
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