Handsfree Shuts Down Automaticallly In Sunshine; Pd Calibration - Nokia NHL-2NA Series Troubleshooting Instructions

CCS Technical Documentation
Figure 5: Most important receiver and transmitter components
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Handsfree shuts down automaticallly in sunshine

It is normal, if this behaviour occurs only in high ambient light conditions, e.g. direct
sunlight, and no repair actions are needed. If this problem occurs also in low ambient
light conditions (outdoors when the phone is not facing the sun), check that capacitors
C273, C274 and C275 are placed correctly.

PD calibration

Proximity Sensor Calibration tool is shown in the Figure 4 Proximity Sensor Calibration
tool. Parameters that are calibrated and saved to PMM are gain, detection threshold and
fault detection threshold. When you start the calibration tool, the values in the PMM are
shown in the left column. Second column shows start values used in calibration, they
are defined by R&D. Calibration consists of two phases. First gain and detection thresh-
old are calibrated. If this calibration is finished successfully, software starts fault thresh-
old calibration; fault threshold cannot be calibrated alone. Offset value(s) are used to
adjust the thresholds to compensate possible wearing of the PD. To help troubleshooting
phone SW response is one of the 13 messages that are explained in the next chapter.
Successful gain and detect threshold calibration tells that optoelectrical components are
OK. Note! Values in this picture might change.
Issue 1 07/02
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Figure 6: Proximity Sensor Calibration tool
¤Nokia Corporation
NHL-2NA
R347
C275
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