SyncMaster 570B TFT / 580B TFT 4-54 Troubleshooting4-7 Microphones Don’t WorkNoDoes the PC’s soundprogram operate well?Check the PC’s sound programand compatibility.YesOKNoDoes the External Microphonework? Check the CN803 jack.YesNoIs the connection between the PCand monitor secure?Connect the cable between the PCand monitor.YesOKNoCan you hear any sound fromthe Headphones?Check CN802 on the Audio PCBand related circuit D805, D806,R811,R812.YesNoIs the Internal Microphoneconnector attached?Check the connection betweenCN808 on the Audio PCB and theInternal Microphone.YesNoDoes the Internal Microphonework? Check Q801 and related circuits.Yes4-8 Headphones Don’t Work