Weird problem with a 25K7501 chassis..

Pengo13

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I'm guessing that it's the chassis causing the issue...... The monitor has an awesome picture, but if my kids slam on the control panel, the brightness is affected. It goes from normal brightness to high brightness. Doesn't happen all the time, but it happens.

I removed the chassis and resoldered the flyback thinking that may be the issue, but it has not helped. I also checked the chassis for any loose connections, broken traces, etc. Nothing obvious....

Again, the picture looks great, but the annoying brightness issue is getting to me already. Is it a bad flyback? Is it a ground issue?

Any help is appreciated......
 
It could be internal to the flyback but it could also be anywhere in the brightness circuit or black circuit or even a color circuit. I'd start by checking all of the solder points on both the chassis and neck board.
 
I might be stating the obvious here but if you could ask your kids not to slam the control panel the problem should clear up.

Sorry for that but I couldn't help it. You might also want to check the monitor control board.
 
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They've stopped....but I haven't!! The game is just too much fun.

Anymore ideas?
 
some cabs mount the remote board underneath the control panel, like just below the bottom of the monitor glass bracket... is this the case with yours?

there's a possibility that if the kids (or you :)) were hitting the sweet spot it might make the brightness pot tweak out if it's got cold solder or one of the pot legs is barely attached.

I sound like a broken record talking about these, but the 2 Blitz cabs I got at auction had a K7500 and a U5000 and they were a friggin mess with the cold solder or fried solder pads. the K7500, instead of re-capping the monitor and reflowing the solder joints on the remote board to fix the brightness/contrast pots they had the flyback jacked way up.

WG seemed to produce some real winners during this span of time, so I'd just check that everything's tight and the solder's fresh before going too deep into it.
 
The remote card is to the side of the cabinet, but I will check tonight to make sure that everything is good with it.....Thanks
 
Yeap.....it was the remote board.....quick fix....Thanks all for the help.
 
Very common to have the remote adjust board develop cold solder joints on the connector header and the pots themselves. Sometimes a trimpot will actually get broken.

Glad yours was just a simple resolder.
 
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