Power system checkoutTo verify a symptom, do the following:1. Turn off the computer.2. Remove the battery pack.3. Connect the ac adapter.4. Check 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. 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 powersupply checkouts:v “Checking the ac adapter”v “Checking operational charging”v “Checking the battery pack” on page 54v “Checking the backup battery” on page 54Checking the ac adapterYou are here because the computer fails only when the ac adapter is used.v If the power-on indicator does not turn on, check the power cord of the acadapter for correct continuity and installation.v If the computer does not charge during operation, go to “Checking operationalcharging”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 thefollowing figure:123(20V)Pin Voltage (V dc)1 +202 03 GroundNote: Output voltage of pin no.2 of the ac adapter may different from the oneyou are servicing.3. If the voltage is not correct, replace the ac adapter.4. If the voltage is acceptable, do the following:v Replace the system board.v If the problem persists, go to “FRU tests” on page 51.Note: Noise from the ac adapter does not always indicate a defect.Checking operational chargingTo check whether the battery charges properly during operation, use a dischargedbattery pack or a battery pack that has less than 50% of the total power remainingwhen installed in the computer.General checkout 53
