Lenovo ThinkPad 380ED ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 546

If the power-on indicator does not turn on, check the power cord of the AC Adapter for correct continuity and installation. 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: Pin Voltage (V dc) 1 +15.5 to +17.0 2 Ground If the voltage is correct, make sure the connection between DC/DC card and system board is not loose. Replace the DC/DC card. If the problem is not corrected, replace the system board. If the problem persists, go to "Undetermined Problems" on page 561. If the voltage persists, go to the next step. 2. Unplug the AC Adapter cable from the ac power outlet and wait 5 minutes or longer to allow the overvoltage 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 defect. Checking the Battery Pack: If the battery pack has a problem, do the following: 1. Power off the computer. 2. Remove the battery pack and measure the voltage between battery terminals 1 (+) and 4 (−). See the following figure: 534 IBM Mobile Systems HMM