Siemens SL10 Repair Documentation page 28

Information and Communication Products
7.2.2 Fault Symptom on GSM-Tester:
7.3 Priority:

........ Mandatory

........ Repair

........ Optional

........ Not Yet Defined
7.4 Repair Documentation
7.4.1 Description of procedure:
7.4.1.1 Diagnosis
7.4.1.2 Repair by component change
V1.3
Communication Devices
Handset fails with loud humming noise in echo loop.
The 31µH coil is used in the step up converter which is generating a
6.0 V supply voltage for the power amplifier out of the 2.8V battery
voltage.
If the coil is mechanically damaged (broken) it produces heavy
interference with the acoustical elements of the SL10 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
replaced.
Use hot air to remove defective coil.
Avoid excessive heat!
Page 28 of 31 ICP CD ST
D. Schnoor
08/98