IBM 2621421 Hardware Maintenance Manual - Page 34

If the measured voltage is correct, replace the system board. If the problems still persist, go to "Undetermined Problems" on page 45. If the voltage is not correct, go to the next step. 2. Unplug the AC Adapter cable from the AC power outlet and wait for five minutes or longer to allow the over-voltage protection circuit of the AC Adapter 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 the Operational Charging: To check operational charging, use a discharged battery pack or a battery pack that has less than 50% of the total power remaining when installed in the computer. Perform operational charging: 1. If the battery indicator does not turn on, remove the battery pack and leave it to return to room temperature. 2. Reinstall the battery pack. If the charge indicator still does not turn on, replace the battery pack. Checking 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(-). See the following figure: Terminal 1 2 Signal / Voltage (V dc) Sense Power ( > 8 V dc) 26 ThinkPad i Series 1400 HMM