Nokia RM-42 Service Manual page 186

Nokia Customer Care
Here are some hints for ALS troubleshooting; the following troubleshooting diagram refers to these:
• Phoenix LED control tool also shows you luminance. The correct luminance in darkness is <20lx, and in office
environment 100-2000lx. The luminance value depends strongly on the light source and the angle of the
phone, so these values are only a rough guideline.
• LED driver control voltage measurement points can be found from
6–30) section. When backlight brightness is set to 100%, both GENOUT-signals are low, and enable PWM is
100%.
• Phoenix has an ambient light sensor calibration tool for changing calibration values. The pull-up resistor
calibration is done first:
a Cover the light guide (upper part of the A Cover).
b Click 'Start' and 'Write'.
c Manually change the ambient light sensor value to the default value. There is no special tool for this, but
you have to perform calibration normally and then set the "Co-efficient" result to '1' before writing it to
the phone memory.
Page 6–28
Figure 50 Ambient Light Sensor Calibration window
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BB Troubleshooting and Manual Tuning Guide
LED driver troubleshooting (Page
RM-42
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