4.12 Microphone Trouble. LG KG370

4. TROUBLE SHOOTING

MIC_P

MIC_N

4.12 Microphone Trouble

CIRCUIT

VMIC

R217

1K

C230

18p

L205

1K

L206

1K

C227

39p

C228

10u

R219

2.2K

39p

C226

C229 0.1u

C232 0.1u

C231

39p

R221

2.2K

C235

39p

1

2

MIC200

OB4-15L42-C33L

CHECKING FLOW

START

Voltage VMIC of U103

= 2.0V?

Yes

Check the Solder condition

No

No

Replace U103 or Change the board

Re-solder or replace the Component

Yes

Check the signal Level at MIC_P(Key).

Is it about 1.2~1.5V DC with a few tens mV

AC?

Yes

Microphone will work properly.

No

Re-solder or replace the microphone

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