Communications
Confidential 20 COM MD CC GRM T
J. Junggebauer
Version 1.0 July 2005
6.7 Earphone capsule/ receiver faulty
Affected unit: Handset
Diagnosis code IRIS: 72100 (ACOUSTICS / RECEIVING / EARCAP)
Repair level: Level 1
Components: Earphone capsule/ receiver
Needed equipment: Multimeter
Working material: None
Diagnosis:
The diaphragm of the earphone could be affected by deposits with increasing age.
There will be a higher attenuation when measuring RLR (receiving loudness rating).
In most cases the earphone capsule is defective.
If there is no noise audible on the earphone when making a sidetone check it’s also
possible that the wire of the coil is broken.
Check the resistance of the coil with a multimeter.
The typical resistance is appr. 120 ohms. In other cases replace it.
Repair:
Replace earphone capsule.
Test:
Put the repaired board in a testhousing.
Make a sidetone check by blowing into the microphone and checking the volume
of the noise on the earphone.
If there is a telephone tester with acoustic testhead make a RLR-test and check
whether the attenuation is o.k..
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