![background image](http://html1.mh-extra.com/html/ibm/thinkpad-a21m/thinkpad-a21m_hardware-maintenance-manual_4074778044.webp)
3. Remove the battery pack (see “1010 Battery pack” on
page 60 ).
4. Remove the backup battery (see “Checking the battery
5. Measure the voltage of the backup battery. See the
following figure.
Red (+)
Black (-)
Wire
Voltage (V dc)
Red
+2.5 to +3.2
Black
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.
Checkout guide
38
ThinkPad A20m/p, A21m/p, A22m/p
Summary of Contents for ThinkPad A21m
Page 4: ...iv ThinkPad A20m p A21m p A22m p...
Page 28: ...Laser compliance statement 22 ThinkPad A20m p A21m p A22m p...
Page 76: ...Removing and replacing a FRU 70 ThinkPad A20m p A21m p A22m p...
Page 78: ...continued Removing and replacing a FRU 72 ThinkPad A20m p A21m p A22m p...
Page 108: ...continued Removing and replacing a FRU 102 ThinkPad A20m p A21m p A22m p...
Page 157: ...Notices ThinkPad A20m p A21m p and A22m p 151...
Page 158: ...Part Number 23P0896 1P P N 23P0896...