Lenovo ThinkPad 380ED ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 146

If the resistance is not correct, replace the battery pack. If the resistance is correct, replace the DC/DC card. If the problem persists, replace the system board. 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 Backup Battery" on page 157). 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. Port Replicator Checkout Use the following procedure to isolate a port replicator problem. A port replicator attaches to the system expansion connector at the bottom 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. 5. Reconnect the failing device directly to the computer. (If another device is already connected to the computer, remove it first.) 134 IBM Mobile Systems HMM