Checking The Ac Adapter; Checking Operational Charging; Checking The Battery Pack - Lenovo ThinkPad T520 Hardware Maintenance Manual

Checking the ac adapter

You are here because the computer fails only when the ac adapter is used.
• If the power problem occurs only when the docking station or the port replicator is used, replace the
docking station or the port replicator.
• If the power-on indicator does not turn on, check the power cord of the ac adapter for correct continuity
and installation.
• If the computer does not charge during operation, go to "Checking operational charging" on page 33.
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 following figure:
3
2
1
Note: Output voltage of pin no.2 of the ac adapter may different from the one you are servicing.
3. If the voltage is not correct, replace the ac adapter.
4. If the voltage is acceptable, do the following:
• Replace the system board.
• If the problem persists, go to "FRU tests" on page 31.
Note: Noise from the ac adapter does not always indicate a defect.

Checking operational charging

To check whether the battery charges properly during operation, use a discharged battery pack or a battery
pack that has less than 50% of the total power remaining when installed in the computer.
Perform operational charging. If the battery status indicator or icon does not turn on, remove the battery
pack and let it return to room temperature. Reinstall the battery pack. If the charge indicator or icon still does
not turn on, replace the battery pack.
If the charge indicator still does not turn on, replace the system board. Then reinstall the battery pack. If it is
still not charged, go to the next section.

Checking the battery pack

Battery charging does not start until the Power Manager Battery Gauge shows that less than 96% of the
total power remains; under this condition the battery pack can charge to 100% of its capacity. This protects
the battery pack from being overcharged or from having a shortened life.
To check your battery, move your cursor to the Power Manager Battery Gauge icon in the icon tray of the
Windows taskbar and wait for a moment (but do not click), and the percentage of battery power remaining
is displayed. To get detailed information about the battery, double-click the Power Manager Battery
Gauge icon.
(20V)
Pin Voltage (V dc)
1 +20
2 0
3
Ground
.
Chapter 3 General checkout
33