"I have a 35" Proscan 35123 direct view TV with a CTC169EJ5 board.
Manufactured in March of 96. I have replaced all the recommended parts
in the power supply and all voltages during idle and run are right on.
The original problem was a shorted HOT which was replaced along with
Q4302, Q2906, C4401, C4402 and C4403. I have had the flyback out and
it's resistances seem OK. A couple of times during the power supply
rebuild I put the board in the TV to put it in run and check some
voltages. When I turned it on it only had a bright narrow band across
the screen. Sound has always been fine. I tapped the flyback and it
came back to full screen. I have replaced Q4201 and Q4202 seems OK.

When the power supply rebuild was finished and I thought all was well
and we sat down to watch it, the thing suddenly popped through the
speakers and shut down. It does not try to restart but can be turned
back on by remote or power button on front panel only to pop and shut
down again. There is no certain time for shut down. It may be a
minute or two or just seconds. I see no burned, bulged or obviously
bad parts. The voltages don't appear to jump before shut down so I
don't think it is over voltage. The 143 volts at CR4116 drops then
comes back up in standby.

Now the picture has gone to a bright narrow band all the time with the
antenna hooked up and a dim thin rainbow colored football shape without
antenna. I have replaced U4501, CR4504, SCR501, Q4507, and Q4505. I
have checked the voltages in this area. All are good except pin 6 and 1
on U4501 are dead. All voltage around Q4801 are dead and there is no
voltage at the B and E on Q4803. The only thing I could find was a
cold solder joint where the yoke wire was hooked to the board causing a
resistance between the yoke connector and connection on the board. The
yoke resistance checks good.

The funny thing is it will stay on indefinitely while no antenna is
hooked to it but put the antenna on so it would have sound and picture
it pops and shuts down.

I plan on doing what I can but I have no scope. I have experience
building tube audio amps and understand tubes well but don't know much
about sand(transistors).
Any advice anyone can give will very much appreciated.