Lenovo Thinkpad L570, Руководство по техническому обслуживанию аппаратной части

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4. Check that power is supplied when you turn on the computer.
5. Turn off the computer.
6. Disconnect the ac power 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:
•
“Checking the ac power adapter” on page 33
• “Checking operational charging” on page 33
• “Checking the battery pack” on page 34
• “Checking the coin-cell battery” on page 34
Checking the ac power adapter
You are here because the computer fails only when the ac power 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 power 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 power adapter, do the following:
1. Unplug the ac power adapter cable from the computer.
2. Measure the output voltage at the plug of the ac power adapter cable. See the following figure:
Pin
Voltage (V dc)
1 +20
2 0
3 Ground
(20V)
1
3
2
Note: Output voltage across pin 2 of the ac power adapter might differ from the one you are servicing.
3. If the voltage is not correct, replace the ac power adapter.
4. If the voltage is acceptable, replace the system board.
Note: Noise from the ac power adapter does not always indicate a defect.
Checking operational charging
To check whether the battery pack charges properly during operation, do the following:
Note: Before you begin, install a discharged battery pack or a battery pack that has less than 50% of the
total power remaining in the computer.
1. Discharge the battery pack until the remained battery power is less than 50%.
2. Connect the computer to ac power to charge the battery pack. If the battery status icon in the
Windows
®
notification area indicates that the battery pack is not charging, remove the battery pack
and let it return to room temperature.
3. Reinstall the battery pack. If the battery pack is still not charging, replace the battery pack and refer to
“Checking the battery pack” on page 34 to check the original battery pack.
4. Check the battery status icon again. If the same error still exists, replace the system board.
Chapter 3
.
General checkout
33