AOC 55C2U-DVB, Service Manual

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7. Poor sound
8. No VGA input signal
Switch to other audio input, check whether DVD
input and PC main board input has sound
Poor sound refers to without sound or with noise; check
whether the selection of sound system is proper
No sound; check whether remote control mute is
selected and switch sound system
No sound for other inputs; check the sound
amplifier and the shared control circuit
There is sound for other inputs,
replace TV tuner or control chip
YES
YES
NO
NO
VGA signal input does not respond, the screen
prompts “Please input signal”, check whether PC
signal source and signal line is normal.
Check VGA signal input board and see whether the row
and field sync signal protection diode is broke down Replace PC or signal line, check
display VGA plug for looseness
Replace the motherboard or
factory reset is normal
Replace the 5.6V Zener diode
on the motherboard
NO YES
YES
NO
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