Zenith SG5745H9 Again ... Horizontal question

[rwagoner]

Hello ... me again, still with the Zenith Advanced System 3 27" solid state console, model SG5745H9. It uses a 9-959 main board, and a 9-754 Sweep board.

I never got around to fixing the "jumpy" picture because it wasn't a priority, and it seemed to go away either if left on long enough OR if unplugged long enough.

Recently it had been left unplugged for a long time; my son then used it and it worked fine for some video gaming. But he left it plugged in. Today when I turned it on, the picture seems to be showing a horizontal hold problem, but interestingly enough, the on screen menus show fine. Is this a case of "change all the capacitors in one area on one board," or is there something specific I should be looking at? Hopefully it's related to the previous problem and I can finally get it working fine again.

THANK YOU as always. Retirement soon ... will have more time for my old stuff ...

[old_tv_nut]

The on screen menu timing is generated from the sweep pulses, so it will display properly even if the sync isn't working. So, the onscreen menu section is OK, but the sync is not.

[rwagoner]

Originally Posted by old_tv_nut

The on screen menu timing is generated from the sweep pulses, so it will display properly even if the sync isn't working. So, the onscreen menu section is OK, but the sync is not.

Is there any part of the board I should be looking at, or should I plan to replace all the capacitors on the (I assume) board that has the inputs?

I may be assuming incorrectly, but am thinking that it is a capacitor because of the way it changes if left unplugged vs. being plugged in (I unplugged it today for a few hours and it worked better, though not perfect).

[old_tv_nut]

Sorry, I'm not familiar with the details of that set, so I hope someone else can make suggestions.

[Zenith26kc20]

Is this a picture in picture set? If so, the picture in picture modules had a lot of capacitor problems.

[zeno]

Originally Posted by Zenith26kc20

Is this a picture in picture set? If so, the picture in picture modules had a lot of capacitor problems.

Model ## says its a high end set so would have PIP. A short video of the
problem would help a lot. Caps are the best suspects but its best
to narrow the prob down to a stage & just change a few. Shot gunning
the caps OFTEN leads to bigger problems & wasted $$$
BTW does this chassis have 2 large modules ? A HV / power supply
& a signals board with slots for sub-boards ??
Good luck
Zeno
LFOD !

[rwagoner]

Originally Posted by Zenith26kc20

Is this a picture in picture set? If so, the picture in picture modules had a lot of capacitor problems.

No picture in picture. I think that was the next model.

[rwagoner]

Originally Posted by zeno

Model ## says its a high end set so would have PIP. A short video of the
problem would help a lot. Caps are the best suspects but its best
to narrow the prob down to a stage & just change a few. Shot gunning
the caps OFTEN leads to bigger problems & wasted $$$
BTW does this chassis have 2 large modules ? A HV / power supply
& a signals board with slots for sub-boards ??
Good luck
Zeno
LFOD !

No sub boards/slots. Two decent-size boards - "sweep" and "main," both of which were used in quite a few models of the era, I believe. We bought this about 1990 I think.

I'll get a video asap ... maybe by tomorrow?

One quick question - if leaving it plugged in, but turned off, makes a difference, is it possible I should be looking at power supply voltage issues? Seems like the video circuits should be "cold."

Would it also help to have photos of the boards themselves?