Display And Keyboard Backlight Troubleshooting; Als Troubleshooting - Nokia RM-132 Service Manual & Parts Manual

RM-132; RM-133
Nokia Customer Care BB Troubleshooting and Manual Tuning Guide

Display and keyboard backlight troubleshooting

Context
The device has one LED driver that provides current for both display and keyboard backlights.
Keyboard backlights are turned ON only in dark conditions. This is controlled by the Ambient Light Sensor
(ALS). Also the brightness of the display is adjusted by the ambient light sensor.
You can enable/disable ALS with the help of Phoenix service software.
Display brightness can be adjusted manually, if ALS is disabled. If the ambient light sensor is enabled, it
adjusts the display brightness automatically.
Troubleshooting flow

ALS troubleshooting

Context
• If a phototransistor is broken, replace it with a typical phototransistor.
• If the phototransistor is changed, the calibration value in the phone memory has to be changed to the
default value '1'.
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