• Make sure that you have completed Display and keypad backlight troubleshooting first before 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 LED driver troubleshooting 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.
Figure 44
Ambient Light Sensor Calibration
window
RM-132; RM-133
BB Troubleshooting and Manual Tuning Guide
Nokia Customer Care
Issue 1
COMPANY CONFIDENTIAL
Page 6 –45
Copyright © 2006 Nokia. All rights reserved.
