Cause for CRT Monitor Jittering?

[sideburn]

I happen to have an STR30130 here from another repair. Would that work as a replacement to the STR30135? I assume not since the output is 5v less.

[m k]

It's 4% down, manual has bigger differences, your call.

I dont have anything that can do PAL.

Both Atari schematics have internal PAL something.
No idea what it really is or what kind of sync differences it can give.

Monitor has NTSC colors so possible PAL picture is most likely without colors.
PAL H-sync is close enough but V-sync is a bit low, -8Hz is accepted, if I understood the manual.

Monitor manual has also that its resolution is 250 TV lines.
Educated guess is that one TV line here is two scanlines high.
My guess is that your demo pictures are non-interlaced first field stuff only.
Seems also that I'm actually unaware how CGA picture is actually generated, from manual I got an impression that it's 200 lines interlaced.
Do you have any true NTSC video sources of 525 interlaced scanlines?

Can you lend an alternative power source, like inverter or so?
Monitor manual states that 50Hz is accepted.

[floobydust]

OP look at that video isolator (jack) board, maybe post pics of it.
I would not change from a 135VDC to 130VDC regulator, it will scuttle the set's calibration and lead to a goose chase.

[sideburn]

It's 4% down, manual has bigger differences, your call.

I dont have anything that can do PAL.

Both Atari schematics have internal PAL something.
No idea what it really is or what kind of sync differences it can give.

Monitor has NTSC colors so possible PAL picture is most likely without colors.
PAL H-sync is close enough but V-sync is a bit low, -8Hz is accepted, if I understood the manual.

Monitor manual has also that its resolution is 250 TV lines.
Educated guess is that one TV line here is two scanlines high.
My guess is that your demo pictures are non-interlaced first field stuff only.
Seems also that I'm actually unaware how CGA picture is actually generated, from manual I got an impression that it's 200 lines interlaced.
Do you have any true NTSC video sources of 525 interlaced scanlines?

Can you lend an alternative power source, like inverter or so?
Monitor manual states that 50Hz is accepted.

I can’t think of any other power supply options off hand or an easy way to get a PAL signal.

One thing to note is this monitor has been fine as my go to composite video monitor for all of these vintage computers for years and then started the jittering and now the horizontal rippling later on.

[sideburn]

OP look at that video isolator (jack) board, maybe post pics of it.
I would not change from a 135VDC to 130VDC regulator, it will scuttle the set's calibration and lead to a goose chase.

I’ll take some pics of the video board today and post.
Any other caps you suggest I replace?

Lots of them are those ELNA brand that have a bad rep.

[sideburn]

OP look at that video isolator (jack) board, maybe post pics of it.
I would not change from a 135VDC to 130VDC regulator, it will scuttle the set's calibration and lead to a goose chase.

Cracked her back open today and replaced the STR30135 with a new one I received in the mail. waving is still there. Also just an FYI the a/v input board has two composite a/v inputs A and B and both are behaving the same way. So far I’ve replaced several caps, the bridge rectifier and the str30135. 🤷‍♂️

The problem does seem to be subtler now or better after it warms up. At least it seems that way right now. Maybe a fluke though… this ones a tough one.