Another jittery Sanyo EZV

MaximRecoil

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I just finished a cap kit (using Bob Roberts' "Plus Kit with 9 more chassis caps"), and there was no change. The jitteriness is slight, but constant and at a fairly fast frequency. It does not go away as the monitor warms up. The monitor's picture looks perfect in terms of color, brightness, etc., aside from the jitters.

I asked Bob Roberts about it and he said:

Bob Roberts said:
No magic answer for jitters... there are many things that could be
responsible from the input to the output to the CRT.

There has to be some causes of jitters that are more common than others, and I'm guessing that there are some areas that can be eliminated because they couldn't possibly cause jitters.

Any idea where I should start?
 
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I forgot to look at the stickied Sanyo EZV flowchart. For the jitters it says:

1. Test and/or replace VR1 & VR2 on the game boardset
2. Test and/or replace VR352, VR353, VR354 on the monitor control PWB

I'm using this monitor with a Super Punch-Out boardset. It doesn't have VR1 & VR2 does it?

So are those pots on the monitor control board a common cause of jitters? If replacing those doesn't work, what then?
 
I didn't change the filter cap. B+ is 109.6 VDC. I'm not sure how to adjust it to 108 VDC.

Edit: I adjusted it to 107.9 VDC. That is as close as I can get it. No change with the jitters.
 
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Similar issue....THREADJACK! :)

I just got a DK boardset and it is doing the same thing on my 20EZ. Just slightly moving left and right every now and then. It's not terrible but I notice it and it bothers me. When I had this monitor running a 60-1 and a Mario Bros it was fine.

I adjusted VR1 and the image moves up and down as it should. When I adjust VR2 the screen loses sync, no mater how much I turn VR2 sync will not restore until I power down then back on. Any ideas for this? Replace VR2 pot?
 
So I finally got around to working on this monitor again. I replaced the filter capacitor (C606) and I replaced all 5 pots on the monitor control board with new ones (VR351 through VR355), and there was no change.

Remember, this is a Super Punch-Out boardset and it has no VR1 & VR2, plus the jitters are definitely a monitor issue, because the machine's original monitors don't jitter when hooked to the same boardset.

So the two original Sanyos in the machine don't jitter, but both of the Sanyos that I want to replace the originals with (because they have perfect tubes, i.e. no screen burn and they have bright, accurate colors), jitter. It is weird that they both have the same jitter issue, because they have completely different histories; i.e., they didn't come from the same machine, nor even the same part of the country. I've only tested them with them sitting on the floor next to the SPO machine ... would it make any difference if they were actually installed in the machine (maybe something to do with ground)? I'm thinking: probably not.

I took a video of it but unfortunately, the jitteriness doesn't show up on it. The video is either not high enough quality to capture it or doesn't have a fast enough frame rate (there isn't a lot of movement in the jitter motion, but it is quite rapid).

Does anyone have any other ideas? Could the flyback transformer be causing this?
 
i have noticed that on my dk after deluxe capping monitor and replacing B+pot, it has a very slight shake, but it is very slight and not consistent. it would be nice to know if this is a problem that may get worst and nip it in the ass now.
 
Have you tried adjusting the horizontal hold knob a bit?
Yes. I've adjusted both the horizontal hold and the vertical hold in both directions until the picture rolled, and it had no effect on it whatsoever; i.e., as you turned those pots it didn't affect the frequency of the jittering at all.

By the way, the jittering is on the vertical axis; i.e., up and down jitter motion. It is also fairly slight; like if this were being used as a TV viewed from across the room you wouldn't really notice it. I've read in a forum post that some jitter is normal in Sanyo monitors, but my original Sanyo monitors in the SPO are rock steady, but they have other problems; i.e., weak tubes, dull colors, and screen burn; and the original upper monitor has especially weak/dark reds.

I might try swapping the perfect tubes from these jittery monitors onto the chassis/frames of the original monitors. I'll bet the original lower monitor would be perfect then, but I don't know about the original upper monitor, because I don't know if those weak/dark reds are caused by its chassis or its tube.
 
I have the jitters too in my DKjr - didn't go away after a cap kit, etc. Drives me nuts because the monitor is (otherwise) perfect picture.
 
I've only tested them with them sitting on the floor next to the SPO machine ... would it make any difference if they were actually installed in the machine (maybe something to do with ground)? I'm thinking: probably not.

As it turns out, it does make a difference if they are actually installed in the machine, but not because of anything to do with ground. When viewed through the cabinet's tinted plexi bezel, the jitters become imperceptible. Remove the plexi and look directly at the monitors, and you can see the jitters again. It is weird. I'm sure there is a scientific explanation for it, but I don't know what it would be.

So before made that little discovery, I had already swapped the perfect tubes over to the original chassis and frames. When I finished doing that and tested them on the floor beside the machine, they still jittered. I was thinking, "How can this be? Are the tubes themselves causing the jitters?" But at least the weak/dark reds problem with the upper monitor was solved, and the raster looked great on both of them due to the perfect tubes, so I said, "Screw it", and installed them in the machine anyway. And as I said, once the tinted plexi was in place, the jitters were no longer noticeable. As a bonus, I still have the matching 20-Z2AW monitors that originally came with the machine installed in there (albeit with replacement tubes), instead of a random pair of 20-EZVs, so it was worth it.
 
Bumping this old thread to just say THANK YOU. I'm restoring a Punch-Out/Super Punch-Out right now and just recapped both Sanyos. I was dialing them in (outside of the cabinet) and noticed some slight "jitter", mostly the ropes in the ring and a few other fine detailed areas. It's been driving me nuts because everything else looks great. I would never have guessed that the tinted plexi would help eliminate that, but after reading this thread, I grabbed the plexi & placed it over the tube. Low and behold, the jitter was pretty much gone. Amazing and like you said, very weird.
 
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