25" 25K7191 Wells Gardner k7000 board problem....

[arcadepcnut]

I have a question that I need some help diagnosing. I have another 25" wells garner 25K7191.
http://nnmodels.com/breaktime/25k7191.jpg (picture of back of board and tube)
This was a friends machine I was supposed to convert to a mame cab for him but for some reason no arcade monitor likes me at all!Seems I have a problem of some sorts with EVERY one I ever see.
It was a marvel vs capcom cabinet and I removed the motherboard and game. This machine was about 30 feet in the garage and workedfine  before I removed the boards and moved it. I assume the moving it is what killed it. We were gentle and"scooted" the cabinet into my basement for me to work on it. When ready to test the monitor I plugged in the cord and switched it on and I hear pretty loud "zap zap zap zap" etc and look behind and see blue sparks going down the plastic leg on the left side on the back of the board and those blue sparks are going to ground (in the picture this area is circled and is the lower left [note: the green ground wire is not there because I removed it to take the monitor out of the cabinet to better work on it.]) I unplug it and start looking for problems. All I see is this extra piece of ceramic housed equipment that I have never seen before on any other monitor. It is hooked inline to the flyback and tube connector (I have it circled in the picture). It was mounted and the mount broke other than that it looks intact and no damage. I have no idea if this broke during shipping or was already broken when the cabinet was purchased.

I see no shorts on the board (but that doesn

[arcadepcnut]

Sorry the picture is at http://www.nnmodels.com/breaktime/25k7191.jpg

[arcadepcnut]

Just for anyone wondering its the flyback transformer. Its cracked. Found its way to ground.

I need a K7000 chassis that works if you know of anyone that has one.

[Ken Layton]

Zanen Electronics (phone 806-793-6337) has the flyback for $26.95

Flybacks are a high failure item on many monitors. It's a good idea to clean the dust off and examine them for hairline cracks which is a dead giveaway that it's seen better days.

[arcadepcnut]

Hey thanks! I heard this one was not replaceable. I've been told Its a zenith problematic one and that I'd have to buy a whole new board per bob roberts.
http://www.nnmodels.com/breaktime/flyback25k7191.jpg if you want to take a look at the damage.

what do you think? i sure hope its replaceable with the one you mentioned but I dont want to get any hopes up.

BTW I see you post alot on startechjournal as well <wink wink>. I've been hanging out there a little reading.

[Ken Layton]

Look on Star Tech Journals videogame forum for the recent posting of "Flyback Transformers". There was a new company discussed there that has these flybacks. I think it was 'Marta' that gave out a link of www.hrdiemen.es/indexeng.shtml

Zanen Electronics claims to have all the k7000 series flybacks.

[Dak-ak]

I'm not sure how much help this will be for you, but here I go:

First of all, as far as I know, that ceramic thingy is perfectly normal, my monitor has one, and so does "jerryjanis"s (remember seeing one on his website wondering what it is).

Secondly, your monitor is very similiar to mine... I got my cab for cheap because the cab wasn't working anymore... i popped the back, and found a 4-inch jump.  Looked dangerous... the fix was to put a plastic top from a small coffee can between the short and the metal it was sparking to.  It looked like there was a small nick on a piece of black plastic (its up front in your picture.. I hope I remember the right part).  Heres your picture with the locations indicated as close as I can remember..

Hope this helps..

[Ken Layton]

Sometimes arcing from cracks in the flyback can be fixed with silicone glue. You have to clean the case of it real good then go over it with some 99% rubbing alcohol. That will leave it clean and ready for the silicone glue. I have been able to repair a couple of Wells-Gardner flybacks with this method.

[Dak-ak]

Yeah, I'm not worried about fixing it... My dad was talking about some liquid glue stuff he had that should patch it up nicely... but for now a simple isolater will funciton fine...

[arcadepcnut]

Im beginning to wonder if it is the flyback. I'll remove the monitor tomorrow and take some better pictures. I repaired the cracked part of the flyback but as you will note it was only where a screw goes into it and should not have any voltage up there. The monitor is still doing the same thing. The tube powers up and the board goes live but the sparks are still happening at that same location as before. Also I have tried the coffee can lid in different spots and still no change. I hope I am not damaging anything testing. I just touch the plug from the wall into the power supply for less than a second and I can hear and see it zap zap zap....the zaps get progressivly weaker. However if you touch the metal housing you will get a little buzz. It kinda like the week buzz from a 120 so Im thinking it is the incoming power somewhere shorting out and possibly not the flyback since that would make an arc that you could see. I turned off the lights and could see no arcs besides the blue glow from that mounting screw. Maybe its something on the bottom of the board touching the metal chassis frame?! Its weird. All we did was move the unit less than 30 feet and it went from working flawless to this problem. This is my luck. Now Im at the point where Im not so sure it is the flyback but dont know how to proceed troubleshooting. Monitors intimidate me.
Wish I knew more than I do..but hey.. this is the best way to learn..right?!

[Ken Layton]

Are you operating the monitor from the isolation transformer in the game?

If this monitor was in a garage maybe it picked up some moisture in the circuit board. Is it possible that maybe a screw or some small conductive piece of metal or foil rolled under the monitor board when you moved the machine?

[arcadepcnut]

Are you operating the monitor from the isolation transformer in the game?

Yes and the isolation transformer tests fine.

If this monitor was in a garage maybe it picked up some moisture in the circuit board.

Thats what alot of people have been telling me. It has been in my basement for at least 2 weeks now. I dried the monitor out with a blowdryer,

Is it possible that maybe a screw or some small conductive piece of metal or foil rolled under the monitor board when you moved the machine?

This is very possible. Let me check and report back!

Eric

[arcadepcnut]

Update:
Changed the post subject to better reflect whats going on here.

Took the monitor out of the cab. Went to discharge the tube. No charge to tub whatsoever. This is even after powering the monitor up to show someone else the sparks to help me troubleshoot.

Laid the tube on its face and removed board. Examined board and then built a power cord to go from cabinet to monitor. Powered the board up and still sparks going to ground. Can not see anywhere on the board that is sparking other than the ground screw mentioned above.

The fact that the monitor tube had no charge disturbs me.

Here are pictures of the board close up. Can you please look to see if you see any problems that I overlooked? If anyone has any suggestions on where to start testing I will. I still think it might be this flyback.

Top of board:
http://www.nnmodels.com/breaktime/k7000top.jpg
http://www.nnmodels.com/breaktime/k7000top2.jpg
Bottom of board:
http://www.nnmodels.com/breaktime/k7000bottom.jpg

If someone here is 80% sure that the flyback is the problem I'll get one and try it. Assuming I can get one since as I mentioned above there is no replacement. The site mentioned above thinks their flyback will replace the one I have but is not sure.

Also if someone here needs to see pictures from a different angle or better pictures please let me know. I'd like to see this monitor work again

Thanks Ken! (Im saying this because you will probably be one to respond....at least I hope!)
I saw your other post about K7000 and the help you provided there so I'm taking a look at it now!

[Ken Layton]

Yup, looks like a small pinhole with red ooze near the screw in the flyback. So your flyback is shot.

Most W-G k7000 series chassis use # 53X0528-001 flyback (stocked by Zanen Electronics), but since you've got the Zenith built version you may have to do some searching for a compatible replacement flyback.

[arcadepcnut]

Yup, looks like a small pinhole with red ooze near the screw in the flyback. So your flyback is shot.

Most W-G k7000 series chassis use # 53X0528-001 flyback (stocked by Zanen Electronics), but since you've got the Zenith built version you may have to do some searching for a compatible replacement flyback.

your probably right. I just cant see it on the flyback. I have removed the flyback from the board to better examine tomorrow. Im thinking of just replacing the chassis from the guys at 8liners and see what happens. No matter what I do it will be the wrong thing. Thats just my luck. Thanks for looking.