Electrohome G07 wavy picture

[jonner]

I recently came into possession of two arcade machines, both of which have Electrohome G07 boards. I've recapped both of them and while the first one looks way better, the other now has a severe waviness to the top half of the screen. I'll attach a picture so you'll see what I mean. I've been scouring the internet for days for a possible fix and I've tried tweaking everything I know how, although I'm admittedly not that great with electronics. I've checked the B+ and messed with the V-hold and all the other adjustors on the board but nothing seems to work. I'm hoping that someone who sees the picture might know what's up. Before I recapped it, the picture wasn't wavy. It was just washed out and not that colorful. Now the colors are back but the waviness makes the game unplayable. Please help if you can.

[mgb]

Check your B+ at the large white resistor. check the terminal closest to the picture tube and it should be +120.  check at the other end of the resistor and it should be around +145.
if this low, your filter cap may be bad.
also cap c511 is a comon failure...............

hold on I just re read your post, this wavyness started after you capped it.
more than likely you either installed a wrong value or put one in backwards or something.
g07s do have one cap that is silkscreened backwards but I can't remember which one now.

Did you do anything with the main filter cap?

[jonner]

Well I didn't cap it myself. A friend did it for me, so it's hard for me to check his work and he's busy for quite a while so he can't come look at it either. Hmmm... There's no way this could have been caused by me somehow hooking the board up wrong, is there? The only thing I can think of that I might have screwed up are the two wires on the left side of the board that needed to be plugged in. Would reversing them cause the problem? Can I unplug and replug them without discharging the monitor? Thanks for the reply!

[mgb]

the 2 wire plug you're talking about is possibly the degaussing coil. That's ac power so it can go either way and won't give this problem.
The other problems that can be caused by plugging things in wrong are typically sync. From your picture this doesn't look like sync. It looks like the image is doing the hoola and that's typically the filter cap or possibly another cap

[jonner]

I guess it's looking like I better check out the main filter cap. There was no replacement for that in the cap kit I got so maybe that's the problem. Once my friend can come back over, I'll check for wrong value caps as well. Like the song says, the waiting is the hardest part. I want to play Golden Axe now!

[mgb]

Also just from my experience, I find most times I work on a g07, the Flyback should be changed otherwise there are good chances if it blowing soon

[mgb]

Yeah main filter caps don't come with cap kits.
  The picture on your monitor is pretty shot and based on the fact that it was just worked on, I'm betting the problem was caused while being worked on.

[Rickn]

Few things and I have may have missed things already in the threads, but hear goes:
- First off your picture shows a fairly high brightness... flyback is fine, concerned about the green picture perhaps it is the game/
- I assume you have the monitor connected to an Isolation transfomer?? Normaly, if not it will blow the fuse as well as the regualtor and others.

Always happy to help or at least try to.

Rick

[jonner]

I appreciate the reply, Rickn! I think the greenish hue was just that particular screen when I snapped the photo, plus the iPhone isn't the greatest camera out there. I believe I do have it hooked to an isolation transformer. I know the voltage is correct because I measured and adjusted it to 120. I think my buddy and I will go over the cap just some time next week. Like I said before, I hate waiting on it, but I'm kind of at his mercy since he knows way more about this stuff than I do.

[mgb]

I thought if you hooked a g07 up without an iso, it would blow up and have no picture. But I've never done it and may be wrong

[ed12]

it is just a plain bad move to hook up a g07/08 without an iso

from the pic i see the tear look's like video/sync overdrive

yes double chk the cap kit
there is a silk screened 1 from the top thats is wrong
it has to be reversed
u can tell by looking at the bottom

in the sync circuit is a tandaluim 1mf or 4.7mf that will go south and cause that very problem
it must be replaced witha tand,u cannot use a normal electroliytic there
as it is sync control

the main input filter just has to be matched by voltage and mf's
u can go higher just do not go lower

ed