General checkout
21
To verify a symptom, follow the steps below:
1.
Turn off the computer.
2.
Remove the battery pack.
3.
Connect the AC adapter.
4.
Make sure 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.
Make sure 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 adapter” on page 21
•
“Checking operational charging” on page 22
•
“Checking the battery pack” on page 22
Checking the AC adapter
You are here because the computer fails only when the AC adapter is used.
•
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 22.
To check the AC adapter, follow the steps below:
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:
Note:
The illustration of the AC adapter may differ from the actual product.
Please refer to the actual product.
Note:
Output voltage for the AC adapter pin No. 2 may differ 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 “Lenovo B50-50” on page 27.
Note:
Noise from the AC adapter does not always indicate a defect.
Power system checkout
Voltage (V DC)
+20
0
Pin
1
2
2
1
