Lenovo ThinkPad 365E-ED ThinkPad 365, SelectaDock I - Hardware Maintenance Man - Page 208

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 already connected to the computer, remove it first.) 6. Go to "How to Run the Diagnostics" on page 212 and follow that procedure. 7. If the advanced diagnostic device test does not find an error, suspect a problem with the port replicator of the system expansion bus. 8. Power off the computer and reconnect the port replicator. 9. Power on the computer and run the following advanced diagnostic tests: Serial port test with the wrap plug installed on the replicator 196 IBM Mobile Systems - ThinkPad HMM Volume 3