Lenovo ThinkPad 760CD ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 229

a. DC/DC card b. System board If the problem is not resolved when the system board is replaced, go to "Undetermined Problems" on page 235. If the voltage is outside the normal voltage range, do one of the following: - Try these test procedures in a different car, if one is available. - Replace the Car-Battery Adapter if the computer works correctly with the AC Adapter. Note: If the output voltage from the cigarette lighter socket of the car is less than 10.5 V dc, a continuous noise may be heard. The condition of the car battery should be checked by appropriate service personal. Checking the Backup Battery 1. Power-off the computer and unplug the AC Adapter from the computer. 2. Open the keyboard, and remove the diskette drive/CD-ROM drive, the battery pack, and the hard disk drive. 3. Remove the top cover and keyboard unit. 4. Open the keyboard unit; then remove the keyboard card. 5. Remove the backup battery from the keyboard card. (Refer to "1200 Backup Battery, Speaker, Standby Battery" on page 288 to remove the battery.) 6. Measure the voltage of the backup battery. See the following figure: ThinkPad 760 (9546, 9547) 217