Uber sentitive Sanyo EZ-20 ...tap the cabinet, and the picture rolls!

[RareHero]

Uber sentitive Sanyo EZ-20 ...tap the cabinet, and the picture rolls!

This is my neverending Popeye saga. I haven't touched this monitor in about 2 years until today.

Previously, I had done a cap kit, but some of the solder pads were loose. The monitor looked great - but the picture was unstable. If you smacked the side of the cabinet enough, you could get the picture to stick...although with each smack you'd get an electronic "BZZRRT!" sound.

So I figure the problem is probably those loose solder pads. I take the monitor out, find all the loose pads (5 of them!), and fix it up using some jumper wire. Put the game back together - it's definitely better now, no more "BZZRRT!" when smacking the cabinet - however, there's still some vertical hold issue....the picture's a little jumpy, it calms down after warming up a bit...but, so much as flick the cabinet, and it jumps again. Adjusting the V. Hold pot doesn't seem to have much cause/effect...if you're in the extremes, it will roll...but in the middle, it's relatively stable but still at the whim of a cabinet flick.

So- what could be the problem now, causing my vertical hold to be super uber sensitive? Now that I've got the bug to work on this thing again, I wanna solve the problem!!!

Thanks!

 

[gregatron]

Did you check to see if the pots were good? Sounds like a flakey pot to me.
But it could be your Sync connection also.

 

[cdjump]

bad pots, low B+, or a cold solder joint at the connector, or bad connector, or all of the above.

 

[Deadly]

Disconnect the video cable and see if it still twitches to ensure the problem is indeed with the monitor. Without the cable you'll get a greyish/white display.

As previously mentoined you really should check the b+ voltage as well.

 

[p1899m]

and don't forget the pots on the pcb if it has them like other nintendo boards do. They often fail too.

 

[RareHero]

Thanks guys - I'll try reflowing the solder on all the connectors next time I take it out ....

Excuse my ignorance - but what's/where's the B+ voltage? *ducks* ..I've been doing this long enough, I should know!

 

[gregatron]

B+ should be 108 VDC and (if your looking down at the chassis) the adjust pot is below and just to the left of the CRT neck on the chassis (does that make sense?) it's labeled B+ adjust. Your meter should connect to chassis and test point BJ.... At least If I remember correctly it's BJ. Someone will correct me if it's not.

 

[mhanlen1]

Taa-Daa! Here's the diagram. Here is a thread about adjusting the B+. I ripped this image from that thread, by the way.

I found that I had a sensitive video cable, and if you would bump the end where it attached to my Donkey Kong board, the V-Hold would jump. Although it's probably not your case.

 

[RareHero]

Thanks for the link to the B+ tutorial. Pretty easy....so, I did the test. I'm getting 109VDC. Is that good enough to leave it well enough alone, or should I adjust it down?

In any case - I also jiggled the various connectors, and they weren't giving me the picture jump that a cabinet smack did. So, I tried to isolate the most sensitive area by lightly flicking about...and it seemed to be the flyback...when I started jiggling that, I was getting way more picture jumps. I put some pressure on the metal part where the bottlecap looking thing is...the HOT? I forget ...and all of the sudden - fixed! No picture roll when smacking it around! Obvoiusly this is just a "quick fix", but perhaps it isolates where the issue is. Maybe some cold joints? Anything in the flyback area seem like something that would cause vertical picture glitching/jumping?

 

[cadillacman]

Thanks for the link to the B+ tutorial. Pretty easy....so, I did the test. I'm getting 109VDC. Is that good enough to leave it well enough alone, or should I adjust it down?

In any case - I also jiggled the various connectors, and they weren't giving me the picture jump that a cabinet smack did. So, I tried to isolate the most sensitive area by lightly flicking about...and it seemed to be the flyback...when I started jiggling that, I was getting way more picture jumps. I put some pressure on the metal part where the bottlecap looking thing is...the HOT? I forget ...and all of the sudden - fixed! No picture roll when smacking it around! Obvoiusly this is just a "quick fix", but perhaps it isolates where the issue is. Maybe some cold joints? Anything in the flyback area seem like something that would cause vertical picture glitching/jumping?

might also have a cracked boarsd in that area with a trace thats cracked and bately touching. Id repull it and look that area over pretty well...