Lenovo ThinkPad T21 T20, T21, T22, T23 - Hardware Maintenance Manual (April 20 - Page 43
Checking the backup battery, Black
View all Lenovo ThinkPad T21 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 43 highlights
Checkout guide Note: Recharging will take at least 3 hours, even if the indicator does not turn on. If the voltage is still less than +11.0 V dc after recharging, replace the battery. 4. If the voltage is more than +11.0 V dc, measure the resistance between battery terminals 4 and 5. The resistance must be 4 to 30 K . If the resistance is not correct, replace the battery pack. If the resistance is correct, replace the system board. Checking the backup battery Do the following: 1. Power off the computer, and unplug the ac adapter from it. 2. Turn the computer upside down. 3. Remove the battery pack (see "1010 Battery pack" on page 60.) 4. Remove the backup battery (see "Checking the battery pack" on page 36.) 5. Measure the voltage of the backup battery. See the following figure. Red (+) Black (-) Wire Red Black Voltage (V dc) +2.5 to +3.2 Ground v If the voltage is correct, replace the system board. v If the voltage is not correct, replace the backup battery. v If the backup battery discharges quickly after replacement, replace the system board. General descriptions 37