Lenovo ThinkPad T420si Hardware Maintenance Manual - Page 51
Measure the voltage of the backup battery. See the following figure., If the voltage is not correct
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5. Measure the voltage of the backup battery. See the following figure. Wire Red Black Voltage (V dc) +2.5 to +3.2 Ground • If the voltage is correct, replace the system board. • If the voltage is not correct, replace the backup battery. • If the backup battery discharges quickly after replacement, replace the system board. Chapter 3. General checkout 45
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5. Measure the voltage of the backup battery. See the following figure.
Wire
Voltage (V dc)
Red
+2.5 to +3.2
Black
Ground
•
If the voltage is correct, replace the system board.
•
If the voltage is not correct, replace the backup battery.
•
If the backup battery discharges quickly after replacement, replace the system board.
Chapter 3
.
General checkout
45