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If the operational charge does not work, go to
“Checking Operational Charging” on page 323.
Note: There are several types of adapters. The
procedure for checking both types is the same.
1. Unplug the AC Adapter cable from the computer and
measure the output voltage at the plug of the AC
Adapter cable. See the following figure.
1
2
AC Adapter (40W)
AC Adapter (35W)
If the voltage is correct, replace the system
board. If the problem is not corrected, go to
“Undetermined Problems” on page 343.
If the voltage is not correct, go to the next step.
2. Unplug the AC Adapter cable from the ac power
outlet and wait five minutes or longer to allow the
over voltage protection circuit to be fully discharged
and initialized.
3. Plug the AC Adapter cable into the ac power outlet.
4. Measure the output voltage of the AC Adapter.
5. If the voltage is still not correct, replace the AC
Adapter.
Note: An audible noise from the AC Adapter does not
always indicate a defective adapter.
Checking Operational Charging: To check
operational charging, use a discharged battery pack or a
battery pack that shows a yellow or orange battery status
indicator when it installed in the computer.
Perform operational charging. If the battery status
indicator turns orange and the battery charging indicator
turns green within two minutes, replace the AC Adapter.
Pin Voltage (V dc)
1 +18.0 to +21.0
2 Ground
Pin Voltage (V dc)
1 +16.0 +1.0/−0.5
2 Ground
ThinkPad 755CD, 755CDV (9545) 323