Acer 510 An audible noise from the power adapter does not always indi cate a defect.

82 Troubleshooting
If you suspect a power problem, see the appropriate power supply check in
the following list:
“Check the Power Adapter.”
“Check the Battery Pack.”
Check the Power Adapter
Unplug the power adapter cable from the computer and measure the output
voltage at the plug of the power adapter cable. See the following figure
1. If the voltage is not correct, replace the power adapter.
2. If the voltage is within the range, do the following:
Replace the System board.
If the problem is not corrected, see “Undetermined Problems”.
If the voltage is not correct, go to the next step.
Note:
An audible noise from the power adapter does not always indi cate
a defect.
3. If the power problem occurs only when the port replicator is used, replace
the port replicator.
4. If the power-on indicator does not light up, check the power cord of the
power adapter for correct continuity and installation.
5. If the operational charge does not work, see “Check the Battery Pack”.
Check the Battery Pack
To check the battery pack, do the following:
1. Power off the computer.
2. Remove the battery pack and measure the voltage between battery
terminals 2(+) and 7(ground). See the following figure
Pin 1: +19 to +20.5V
Pin 2: 0V, Ground