Sanyo PDP-42XR7K Service Manual page 19

2.3. No sound (TV channel)
Check if the voltage
of N203 pin1, 3, 10,
12, 19, 20 are normal
no
Check power board
yes
Check the wave of
pin 5, 6 of N203
no
Check the wave of
N602 pin 24
no
Check the wave of
TUNER601 pin 11
no
Check TUNER601
and its periphery
17
yes
Check N203 and
its periphery
yes Check N304 and
its periphery
yes
Check N602 and
its periphery