Earphone Trouble - LG MG210 Service Manual

4.15 Earphone Trouble

Block Diagram
EAR-MIC
HSMICBIAS
HOOK_DETECT
Close to ABB
C244
10p
C243 0.1u
HSMICP
C245 4.7u
HSO
R225 120 C247
(1608)
10p
C246
NA
Earphone Detecting Operation
• The ABB operates A/D conversion continuously and if the voltage of "JACK_DETECT" node
goes to 0V and the voltage at "HOOK_DETECT" 0.02V to 0.25V, it detects ear-jack inserted.
• The ABB operates A/D conversion continuously and if the voltage of "HOOK_DETECT" node
goes to 0V, it detects hook switch is pushed.
Earphone Sending Path
• HSMICP is the audio signal from the microphone of the earphone.
• C243, L200 and L201 make the path of the audio signal from the microphone of the
earphone.
• This audio signal is delivered to ABB(IOTA Shrink).
Earphone Receiving Path
• HSO is the audio signal from ABB(IOTA Shrink)).
• C245, R225, L202, and L203 make the path of the audio signal from ABB to earphone.
Close to Ear-jack
R218 0
C231
4.7u
(1608)
1K R222
C235
47p
C240
C241
39p
47p
L200 100nH L201 100nH
L203 100nH
R226
L202 C248 C249
100nH
1K
27p 47p
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4. TROUBLE SHOOTING
EAR_JACK SPEC
MIC
V_IO
C232
10p
R219
10K
C233
10u
R220 R221
(1608)
5.6K 47K
C242
CN200
10p 2
4
3
1
5
C250
10p
R227
JACK_DETECT
33K
C251
27p
GND
Receiver