User Guide

Backlights troubleshooting

The phone has two illumination drivers. One of them provides the LED current for both displays and the media

keys. Either main display or both cover UI display and media keys are illuminated. The other one provides a

constant pre voltage for the EL foil high voltage driver. Both EL foil and high voltage regulator can’t repair

separately because they are part of the UI PWB and glued on C-cover. So all repair activities only refer to the

engine PWB.

RM-135

Nokia Customer Care BB Troubleshooting and Manual Tuning Guide

Page 4 –28 COMPANY CONFIDENTIAL Issue 1