Power System Checkout; Checking The Ac Adapter - Lenovo ThinkPad T61 Hardware Maintenance Manual

Power system checkout

To verify a symptom, do the following:
1. Turn off the computer.
2. Remove the battery pack.
3. Connect the ac adapter.
4. Check that power is supplied when you turn on the computer.
5. Turn off the computer.
6. Disconnect the ac adapter and install the charged battery pack.
7. Check that the battery pack supplies power when you turn on the computer.
If you suspect a power problem, see the appropriate one of the following power
supply checkouts:
v "Checking the ac adapter"
v "Checking operational charging" on page 29
v "Checking the battery pack" on page 29
v "Checking the backup battery" on page 30

Checking the ac adapter

You are here because the computer fails only when the ac adapter is used.
v If the power problem occurs only when the ThinkPad Essential Port Replicator
v If the power-on indicator does not turn on, check the power cord of the ac
v If the computer does not charge during operation, go to "Checking operational
To check the ac adapter, do the following:
1. Unplug the ac adapter cable from the computer.
2. Measure the output voltage at the plug of the ac adapter cable. See the
3. If the voltage is not correct, replace the ac adapter.
4. If the voltage is acceptable, do the following:
Note: Noise from the ac adapter does not always indicate a defect.
28
ThinkPad T61, R61, and R61i (14.1-inch widescreen) Hardware Maintenance Manual
is used, replace the port replicator.
adapter for correct continuity and installation.
charging" on page 29
following figure:
3
2
1
(20V)
Note: Output voltage of pin no.2 of the ac adapter may different from the one
you are servicing.
v Replace the system board.
v If the problem persists, go to "ThinkPad T61, R61, and R61i (14.1-inch
widescreen)" on page 45.
Pin Voltage (V dc)
1 +20
2 0
3 Ground