Complete Fix Solution

Heres the solution that may possibly help fix and repair a microphone failure on Nokia N78 cell phone handset. In Nokia N78 the microphone line track is connected over the keypad flex cable wire connection. If something went wrong and the microphone failed to have an audio signal output during transmission, The problem may possibly lies on a faulty mouthpiece microphone, a damaged flex cable and a faulty microphone signal line paths. This solution below shows the microphones line tracks that needs to be trace after ensuring that the microphone is okay and the flex cable is also okay.


The microphones positive terminal line tracks is connected on pin 22 of the keypad pin connector, while the negative terminal is on the PCB grounds. There is also a bypass capacitor connected to it, if the capacitor is oxidated or shorted due to a wet damaged this also result to microphone failure problem.