LG KE990 Service Manual - Page 115

4. TROUBLE SHOOTING 4.11.4 Microphone for headset MIC for Head_Set path as below: Insert Headset → EAR_SENSE_N(pin8) go 0V → ESM6270 sense Head_Set insertion → MIC signal → U502(audio codec) → ESM6270. R528 100K CN500 21 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 FB504 FM_ANT EAR_MIC_P TV_OUT MIDI_EAR_L MIDI_EAR_R RMT_INT-USB_D+ RMT_ADC-USB_DEAR_SENSE_N VBATT RMT_PWR_ON_N C539 MMP_A_LRCLK MMP_A_BCLK MMP_ADI_ADCDAT MMP_ADO_DACDAT MMP_A_MCLK MID_MICP C539 1u C534 1u AVDD1 7 8 LRC 9 BCLK ADCDAT 10 DACDAT 11 MCLK 4 5 RIP RIN 6 R2_GPIO3 3 L2_GPIO2 1 2 LIP LIN 19 AUXL 20 AUXR 15 16 CSB_GPIO1 24 AGND2 VMID 27 32 MICBIAS ROUT1 29 LOUT1 30 ROUT2 23 LOUT2 25 22 OUT3 21 OUT4 MODE 18 C524 C525 0.1u 10u FB500 HP_EAR_R HP_EAR_L FB501 MIC2P C543 C544 NA NA C531 NA MIC_PWR SPK_OUT+ SPK_OUT- [CN500(headset connector)] [audio codec] MIC2P Start Make a call Try change the h ead set NO EAR_SENSE_N is 0V? YES MIC_BIAS i s 2.7V ? YES make some sound or voice to MIC YES NO NO END Chang e th e Main b'd Chang e th e Main b'd Can you s coping some sound signal at C539? YES Can you s coping some sound signal at C235,L200? YES Work w ell? NO Chang e th e MIC NO Check t he U502 or Change the Main B'd YES END AC21 AC19 AC20 AF19 AE19 AF21 AF22 AF20 AE20 AA20 C200 10p L200 100nH C235 0.1u MIC1N MIC1P C236 0.1u C203 NA C204 NA C238 LINE_L_IN LINE_R_IP LINE_R_IN AUXIN AUXIP MIC2N MIC2P MIC1N MIC1P CCOMP [ESM6270] LGE Internal Use Only - 116 - Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes