PG-1810 Service ManualPANTECH R&D CONFIDENTIAL316.2 Audio Part ( Earpiece, Speaker, Hands-free Earphone, Microphone, Hands-free Mic )6.2.1 No receiving tone heard ( Ear-piece )1. Check C243, U202.J15(R219) and K15(R220) pins, C237 (Ear Signal) for waveform : CP110NO Æ Replace U202, and C243, C237.2. Check to see Earpice and Mani FPCBIf you find out any defect, you replace themCP110