Haier L42C300c Service Manual page 44

4) No sound
Check if the power supply
system is damaged, short
circuit or mis-connected
Check the mute control
Q701,Q704
circuit from
Check the audio input
circuit from U706 to
U705
Check the
input
N
source
Reset
Y
volume
Check the
Y
speakers
N
Y
N
- 43 -
No sound
N
Check if there is sound input
signal
Y
Check if the volume control is
at 0 level or muted
N
Check if there is output at
CN701
N
Check if there is +12V input at
PIN28 OF U705
Y
Check if MUTE PIN of
voltage
N
Check if there is signal input at PIN3
& PIN12 of U705
Y
Replace U705
Service Manual
Model No.:
U705 is low