User Guide

Current pump LED driver troubleshooting

Troubleshooting flow

Ambient Light Sensor (ALS) troubleshooting

Context

• If ALS (Poliwag) is broken, replace it.

• After replacing the ALS, ALS re-tuning is required for example if calibration values of the new sensor are

lost (see instructions later in this document).

• When carrying out the ALS calibration procedure, it is required to have a reference phone, which includes

calibrated ALS. ALS re-tuning instructions below explain why the reference phone is needed.

• Make sure that you have completed Display and keypad backlight troubleshooting (page ) first before

starting ALS troubleshooting.

Here are some hints for ALS troubleshooting:

• In

Phoenix

Display Test tool, there is an

Ambient Light Sensor

window, which shows the luminance. The

correct luminance in darkness is <20 lx, and in office environment 100-2000 lx. The luminance value

depends strongly on the light source and the angle of the phone, so these values are only a rough guideline.

• LED drivers’ control voltage measurement points can be found in the SMPS LED drivers troubleshooting

(page 3–46) and Current pump LED driver troubleshooting (page 3–47) sections. When backlight brightness

is set to 100%, the PWM signal is continuously on high state.

RM-313

BB Troubleshooting and Tuning Guide

Issue 1 COMPANY CONFIDENTIAL Page 3 –47