Als Troubleshooting; Figure 16 Ambient Light Sensor Calibration Window - Nokia N70 Manual

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BB Troubleshooting and Manual Tuning Guide

ALS troubleshooting

Context
• If a phototransistor is broken, replace it with a typical phototransistor.
• The phototransistor has to be also replaced, if calibration values are lost by some other reason (e.g. after
replacing the NOR memory chip D3000).
• If the phototransistor is changed, the calibration value in the phone memory has to be changed to the default
value '1'.
• Make sure that you have completed
starting ALS troubleshooting.
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
1–41) 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 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.
Issue 1
Display and keypad backlight troubleshooting (Page 1–38)

Figure 16 Ambient Light Sensor Calibration window

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