Lenovo ThinkPad 760CD ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 549

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. Checking the Standby Battery (Rechargeable) 1. Power off the computer and unplug the AC Adapter from the computer. 2. Remove the battery pack and keyboard. 3. Remove the standby battery. (Refer to "1100 Standby Battery" on page 586 to remove the battery.) Attention Be careful not to cause a short circuit when measuring the voltage. 4. Measure the voltage of the standby battery. If the voltage between red and black wire of the battery is 3.5 V dc or greater, the voltage is correct. Go to step 10 to verify standby battery operation. If the voltage is less than 3.5 V dc, go to the next step. 5. Plug the AC Adapter into the computer and power on the computer. Attention Be careful not to cause a short circuit when measuring the voltage. 6. With the battery unplugged, measure the output voltage at the connector. Pin Voltage (V dc) + +4.0 − Ground If the voltage is less than +4.0 V dc, replace the DC/DC card. If the voltage is still low, replace the system board. If the voltage is more than +4.0 V dc, power off the computer, replace the standby battery, and go to the next step. ThinkPad 770 (9548, 9549) 537