Nokia NEM-4 Series Troubleshooting Instructions page 28

NEM-4
BB Troubleshooting
Maximum tolerances are:
Reading
Reading
Vbatt SCAL
Vchar
Ichar
BSI
Btemp
Backup battery
Symptom of backup battery fault is
Real Time Clock loses the correct time during short main battery removal.
The same symptom can also be seen when the backup battery is empty. About 30 min-
utes is needed to fully charge the backup battery in the device. NOTE: Backup battery is
charged when the phone is powered or when the device is LOCAL or TEST mode.
Always check the backup battery visually for any leakage or any other visual defect.
Check that the backup battery is correctly mounted in the device before closing the
cover.
Check with Phoenix that backup battery is OK
Measure the voltage of backup battery
• Normal operation when the voltage is > 2.0V
• Fully charged when the voltage is about 3.2V (because of large internal imped-
ance voltage won't stay above 3.0V a long time after charging is disabled)
Enable backup battery charging (start to charge main battery or boot device to LOCAL or
TEST mode)
Measure voltage of backup battery during charging, It should arise if it is not 3.2V, yet.
When the voltage is over 2.0V for sure, check backup battery with Phoenix.
-> In not OK then D190 is faulty.
Ensure that the RTC is running.
Page 6(a)-26
Company Confidential
Check point
Check point
4.2V
8.4V
500mA
75k
273K(47k)
Copyright  2003 Nokia Corporation
Company Confidential
CCS Technical Documentation
Tolerance
Tolerance
± 25mV
± 40mV
± 20mA
± 1.3kohm
± 5K
Issue 1 09/2003