Changhong Electric PT4216, Service Manual, Page: 37 / 62

37
if there is one
state to display
when switch the
source
TV, AV, S-VIDEO,
all no picture
only AV no
picture
no picture only S-
video
only TV no picture
check U400
TDA8759 horizon
and vertical sync.
And clock ok or
not
check TDA8759 horizon
and vertical sync. And
clock output is normal
or not
check TDA8759 power
and peripheral circuit;
change TDA8759
No
check AV board
connector
check UOC3 AV
I/O is ok or not?
joint well
check UOC3 and
TDA9178 power,
bus;
input ok, but output
abnormal
check S-video
connector
check UOC3 and
TDA9178 power,
bus;
check UOC3 S-
video I/O is ok or
not
Yes
check UOC3 31th,41th pin
voltage and peripheral
component is ok or not
check TAD5-
C2F21RW power,
bus and SAW filter
circuit
check and change
TAD5-C2F21RW
Input ok,but output
abnormal