'08 Sansui (Orion) DTV2798 CRT SDTV problem
 

I think this is one of the last 27" CRT TV's that could be bought and, since it's from 2008, it has a built-in DTV tuner.

This one has a strange problem in that in works fine for 1:21 and then it shuts off. I don't have access to a service manual (if there ever was one); so, I'm in the dark as far as checking voltages.

I replaced a few marginal electrolytic caps in the power supply and the cap that always fails in the vertical circuit, just for good measure. I also resoldered some marginal solder connections; but, it's still doing the same thing.

Anyone have any ideas before I use this for target practice?

Are you sure there's no sleep timer that needs disabling? Is that 1:21 minutes or 1 hour 21 minutes? Is it that precise?
Rather interesting, at best.:scratch2:

It's 1m21s; which, I should have been clearer about. I tried the sleep timer and it's turned off. I also tried a button sequence that's supposed to reset the microprocessor; which, didn't help. I'm about ready to neck the CRT, pull the chassis for parts, and concentrate on more worthwhile projects.

The next thing I would try is plugging it into a variac. Reduce the line voltage to a lower level. Try 115, 110, 105 etc. Maybe there is a shutdown circuit, that takes samples of the power supply voltage over that time frame. Those software engineers are really programming all kinds of parameters into the main processor.
Look at cars for example.:yes:

change c403 22uf at 50 volt. located by horiz. drive transformer.....

Thanks! I may have already changed that cap; but, I"ll double check to make sure.