XOCECO LC20H3D, Service Manual

Page: 23 / 55

No sound
Check N8 pin 14, 15, 22, 23, 38,
39, 46,47 (these pins should
have 12V power supply)
Check whether N8 pin 4, 27, 28 are
normal. Pin 4 should be 2.43V,
pin 27 should be 1.46V and
pin 28 should be triangle wave.
Check L302, X604 pin 5 and pin 6.
Check N6 pin 5 and
pin 8 signal.
Check N8's welding
condition.
Check N5 pin 27
and pin 28 signal.
Check N5 pin 67 signal.
Check whether U1 pin 11
have output waveform.
Check N8 pin3, pin 5's input signal.
Replace N8.
Yes
No
Yes
No
No No
Yes
No
No
21
Troubleshooting guide
No raster
Does the logo appear on the screen
when turning on the set ?
Check whether the adapter
supply 12V power to Digital Board.
Check whether X101 is
properly inserted.
Check U125965V. Check whether FUSE is melted.
Replace adapter.
Check whether U18 pin 63
is high level.
Check whether there is R.G.B
output at X601 on TV board.
Replace TV board.
Replace Digital board.
Yes Yes Good
No
Good
No
No No
No