Sanyo image shaking vertically

Volbard

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So I finished capping my 14" Sanyo that's kind of like an EZ over in this thread:
http://forums.arcade-museum.com/showthread.php?t=242346

It seems to be the original monitor for my Warlords cocktail, and it worked fine until a couple weeks ago.

The cap replacement fixed the screen being scrambled, but now it has a new problem. When it is first turned on the image is perfect and stable, but after a few minutes of being on it starts to shake vertically. At first it's just a little vibration, but soon it's bouncing violently up and down like an earthquake.

I can adjust the v-hold and temporarily stop the shaking, but it comes back in a minute or so. Once it's on for a long time I can no longer adjust it away.

Searching this and other forums, I've seen people mention these possibilities for similar problems:

- A cold solder somewhere
- Bad sync signal from the game PCB
- Incorrect voltage at B+
- Bad V-Hold Pot
- Bad Flyback

Any other options or advice for narrowing it down? I may need to reflow everything, but the heat doesn't seem to be great for the board and I'm worried about damaging it with repeated soldering.
 
replace the two with no polarity, and the filter cap.

your snap cap will probably work you may need to unsolder other holes in the pads to make it fit.

i have to do this when replacing the filter caps on K7000, G07 and sanyo's. they are snap caps and have a smaller foot print than the originals.

it's the same with a 4900 and the 4600 as well but with them you have to run a jumper to the snap lead does not reach the old pad.


Peace
Buffett
 
Thanks buffett!

I've ordered those caps, and some pots while I'm at it. I'll see if I can get that filter cap in while I'm waiting for them to get here. I actually had it in once, but the screen was wavy and it wasn't seated well so I went back to the old one. I can probably find a way to get it seated better.
 
Update! Fixed? Probably!?

While waiting for parts I touched up all the solders that looked a little suspect, and put warlords back together. It shook a lot while warming up for the first ten seconds, but otherwise worked great. As the week went on, it worked even better, and stopped even shaking when it powered on.

That's great, but I was suspicious since the room temperature had also been getting lower. I don't want to fix it again later, so I pulled it today and replaced the final caps and the v-hold pot. Put it all back together, and it still works perfectly. So... Probably all fixed!

Thanks again for the help buffett, I appreciate the advice.
 
Not fixed!

As I feared, the shaking came back once the game heated up a bit. I'm not sure where to go from here, has anyone seen this sort of thing before? It's completely vertical, and bounces rapidly up and down but does not roll.

Maybe I should just install some fans?
 
Man, I hate to tell you, but I've got one that's been doing this for about a year and I can't figure it out either. It's just enough on mine to be annoying as hell. 14" sanyo, just like yours... recapped everything, reflowed everything, tried a different gameboard, B+ is dead on, put new pots in, etc. and can't figure out why it's doing it. Sucks.
 
Man, that fan idea is sounding better.

Good luck with yours LyonsArcade, let me know if you figure anything out!
 
This is the fix

O.k. I had this same problem. Replace all the non polarized 22uf caps on the chassis. They
all go bad on this chassis causing this freaking shaking! Once you replace them, your monitor will be fixed. You'll get a small shake here and there once in a while but it's normal. It's very faint after the caps are installed.
 
Interesting, thanks for sharing that barakawins!

I've already replaced all my electrolytic caps, but I only noticed the 4.7uf caps being non polarized. I'm sure our chassises are different, but now I want to double check my 22uf and make sure I didn't put a regular cap in an NP spot.

Someone posted on a youtube video about similar shaking that replacing the diodes near the filter, 601 - 604, fixed the problem for them, so I'm thinking about trying that too.
 
Interesting, thanks for sharing that barakawins!

I've already replaced all my electrolytic caps, but I only noticed the 4.7uf caps being non polarized. I'm sure our chassises are different, but now I want to double check my 22uf and make sure I didn't put a regular cap in an NP spot.

Someone posted on a youtube video about similar shaking that replacing the diodes near the filter, 601 - 604, fixed the problem for them, so I'm thinking about trying that too.
Any update here?
 
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