LG LM-U1050A - Page 9

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Muting circuit Troublrshooting (MUTE condition)
Q752(A102) Base “HIGH”
Q604, Q605(D1302) BASE “HIGH” check
c-COM operation status check
Replace each related TR
Q603(A102) operation status check
Replace when Q603(A102) is defective
c-COM 2PIN(A-MUTE) LINE check
CN942/CN701 connection status
check
MUTE
YES
YES
YES
YES
NO
NO
NO
Unfelt voice
Input check (AUX ➝ 9.36 TUNER ➝ 6/39 TAPE ➝ 7/38CD ➝ 8/37PIN)
Check input and operation status for each function
YES
NO
IC601 20/25PIN output check
Refer to IC401(NJW1190) IC specification
YES
NO
IC601 input check (22/23PIN)
c-COM check and (CLK/DATA check)
YES
NO
IC601 output check (24PIN)
NORMAL
Check IC401 24PIN cover 8V and power circuit
YES
NO
Power operation staus check
R634 180(9.1)V check
YES
YES
NO