GB310 Service Manual
1
PANTECH
6.2.3 Side Tone Not transmitted ( Ear-piece )
Repeat 6-2-1 No receiving tone heard.( Ear-piece )
1. Check to see if Mic + pin is around 1.84V : CP117
NO Check that R142, C202, C135 and R145 is cold solder, broken, short to the other
PCB pattern or not
If you find out any defective part, you replace it.
Set to HP8922M to connect a call and then set to 1kHz with Echo audio mode.
2. Check C140.C141 pins for wave form : CP118
NO Replace MIC
CP117
CP118