User Guide

Nokia Customer Care 6(a) - Baseband Troubleshooting

Company Confidential RH-51/52, RH-67/68

VCHAR over limits

Inspect components that are connected to VCHAR line: filtering capacitors C134, C135,

TVS V130, L130 and fuse F130. If those are OK, change UEM.

ICHAR over limits

Inspect components that are connected to VCHAR line: filtering capacitors C134, C135,

TVS V130, L130 and fuse F130. If those are OK, first change the current sense resistor

R259, if calibration is still not successful, change UEME.

Calibration can be checked using the ADC reading. Known voltages, currents and resis-

tances are fed and read by the ADC reading, read values and known values can be com-

pared.

ADC reading

Divided and scaled battery voltage, battery current, charger voltage, charger current and

BSI values can be read by this tool. Read values a few times before you can be sure that

results are accurate.

Figure 12: ADC reading view

Maximum tolerances:

Reading Check point Tolerance

Vbatt SCAL 4.2V ±25mV

Vchar 8.4V ±40mV

Ichar 500mA ±20mV

BSI 75k (BL-5C) ±1.3kohm

Btemp 273K (47k) ±5K