Fea 209 544/11.C - Ericsson PF 768 Troubleshooting Instructions

PF768, Standard Electrical Repairs
4.3 Microphone out of order.
Open the phone and check for liquid damages.
Wash the system and microphone connector pads if needed.
Make sure the sound channel gasket is properly mounted and free from dust.
Replace the system connector and microphone with a pair you know work. Test the
phone again.
• If the fault remains, measure the resistance of C850 and C851 (both >100
kohms, class A, fig. 4.3). Measure the resistance of R816 (~470 ohms, fig. 4.4,
class A), R817 and R819 (~1 kohms, class A, fig. 4.3). Check the solderings of
N800 (fig. 4.3).
Fig. 4.4
If the fault remains, send the phone to the next level.
4.4 Both the earphone and the microphone of
the phone out of order.
Open the phone and check for liquid damages.
Make especially sure there's no dirt or oxide between the components below the
dome switches (fig. 4.5) and at the system connector pads.
Fig. 4.5

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