Nokia NHL-2NA Series Troubleshooting Instructions page 43

CCS Technical Documentation
1 Set light sensor sensitivity to "minimum". Cover ALD window for example with a
hand.
2 Sensor ADC-reading should be <500 in bright light and in total darkness >900.
3 Vflash1, measured at pull-up resistor pin, should be 2.78V. Check that resistor
R131 is placed, and it's resistance is 22kΩ. Check that resistance between col-
lector and emitter of the ambient light sensor changes, when illumination on the
sensor (from ~5kΩ in high illuminance to ~500kΩ in total darkness). If pho-
totransistor has to be replaced, the detector has to be calibrated. Calibration can
be done only with TDS-11 light source.
4 NTC ( R132) resistance at room temperature is ~47kΩ.
Issue 1 07/02 ¤Nokia Corporation
NHL-2NA
Page 37