Lenovo ThinkPad 380ED ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 48

Checking the Backup Battery 1. Power off the computer and unplug the AC Adapter from the computer. 2. Turn the computer upside down. 3. Remove the DIMM cover and backup battery (see "1010 Battery Pack" on page 59). 4. Measure the voltage of the backup battery. See the following figure. Note: Be careful not to measure the wrong side of the backup battery. Wire Red Black Voltage (V dc) +2.5 to +3.7 Ground If the voltage is correct, replace the system board. If the voltage is not correct, the backup battery has been discharged. Replace the backup battery. If the backup battery discharges quickly after replacement, replace the system board. Common Device Checkout If you suspect a common device problem, see the appropriate power supply check in the following list: "Port Replicator Checkout" "External Display Self-Test" Port Replicator Checkout: Use the following procedure to isolate a port replicator problem. A port replicator attaches to the system expansion connector at the rear of the computer. 1. Power off the computer. 2. Remove the failing devices from the replicator. 3. Unplug the AC adapter from the replicator, if attached. 4. Remove the port replicator from the computer. 36 IBM Mobile Systems HMM