Checking the Operational Charging: To
check operational charging, use a discharged battery pack
or a Battery that has less than 50% of the total power
remaining when installed in the computer.
Perform operational charging. If the battery status indicator
does not turn on, remove the Battery and let it return to
room temperature. Reinstall the Battery.
If the charge indicator still does not turn on, replace the
Battery. If the charge indicator still does not turn on,
replace the DC-DC & BATT board, then the system board.
Then reinstall the Battery. If the reinstalled Battery is not
charged, go to the next section.
Checking the Battery: Battery charging will not
start until the Fuel-Gauge shows that less than 95% of the
total power remains; with this condition, the Battery can
charge to 100% of its capacity. This protects the Battery
from being overcharged or having a shortened life.
Do the following:
1. Power off the computer.
2. Remove the Battery and measure the voltage
between battery terminals 1(+) and 7(-). See the fol-
lowing figure:
1234567
Note: Signal lines, not used in these steps, are used
for communications between the system and
the battery.
3. If the voltage is less than 10.8V (Li-Ion) or 9.6V
(NiMH), the Battery has been discharged, recharge
the Battery. If the voltage is still less than 10.8V
(Li-Ion) or 9.6V (NiMH), replace the battery.
4. If the voltage is more than 10.8V (Li-Ion) or 9.6V
(NiMH), measure the resistance between battery ter-
minals 1 and 3. The resistance must be 390 ohm
(Li-Ion) or 4 to 30K ohm. If the resistance is not
correct, replace the Battery. If the resistance is
correct, replace the DC-DC & BATT board then the
system board.
ThinkPad 390X / i 1700 HMM 33