5.4.1 Description of procedure:
22.214.171.124 Repair by component change
126.96.36.199 Repair by SW-Booting
The 18µH coil is used in the step up converter which is generating a
5.4 V supply voltage for the power amplifier out of the 2.8V battery
If the coil is mechanically damaged (broken) it produces heavy
interference with the acoustical elements of the C25 resulting in a loud
humming noise in the earpiece.
A broken coil can easily be diagnosed by trying to move it with two
fingers. If it moves, the core is broken and the coil has to be
Use hot air to remove defective coil.
Avoid excessive heat!
Watch surrounding components!!
Resolder new coil afterwards
Retest handset after repair by checking the audio quality with the echo
loop of the testprogram.
Page 15 of 34
Information and Communication Products
ICP CD ST