Monitor dims/brightens when I nudge flyback

KidVidiot

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I have a 25" monitor that was really dim when I got it...I apply pressure to the flyback and the picture becomes normal, but it will go back to being dim after awhile. Is this cold solder on the flyback connection? Or is the flyback just on its last leg?
 
Maybe both. Could also be a crack in the PCB around the flyback, or a cold solder joint on a nearby part that is semi-fixed when pushing on the flyback flexes the board slightly.

Pull the chassis and reflow anything that looks iffy, and every pin of the flyback, then check again.

And if it's a K7000, check around the flyback knobs for tiny cracks. If you have some, you probably need to replace it...
 
Mine was flyback

Check and see where you are nudging if it is one of the nobs it is a bad flyback otherwise crack/bad solder. I'm in the process of changing out a flyback that the focus nob is broken inside and the pic gets real dark unless you push or turn that nob then it is normal until it decides to move again.
 
To date, I have repaired HUNDREDS of monitors and found maybe two with cold solder joints on the flyback. To be fair, about 1 in 4 appear that someone had re-flowed the pins in the past as part of troubleshooting a previous repair or a previous cap kit so I would think this would actually more common in games that didn't see much use as they would have original solder due to never having been on a bench before.

What I have found most often (especially on the 25 inch WG K7XXX monitors) is that the focus assembly goes bad. A temporary fix is to put a zip tie around the flyback pressing in on the focus and screen knobs. This will get you by until your new flyback arrives.

I have seen cracks the the PCB around the flyback most often on Sanyo 20 EZV (nintendo) monitors as they have a thin PCB with some easily missed/re-locking nylon pins that can spell disaster when removing the board.
 
yeah just to update this, turns out the nudge only worked on the brightness knob, and after nudging it a few more times, the whole thing crapped out, so definitely a bad flyback I guess.

I then took out the monitor and put in a different working monitor with a sharp image chassis I had sitting on my shelf. I get it all in there and the image is upside down for some reason, even though I know it's not installed upside down. I see that the connectors housing the four colored wires going from the yoke to the chassis have been cut, so I try to rearrange them thinking I put them back in wrong, but at some point while doing this in a cramped space I think I may have pulled or bent one of the plugs out of the chassis, because the next time I turned it on to test I got vertical collapse!

So basically I bought a jamma cabinet with a "working" monitor that didn't really work and then definitely didn't work, and then I killed my replacement monitor too.
 
I see that the connectors housing the four colored wires going from the yoke to the chassis have been cut, so I try to rearrange them thinking I put them back in wrong, but at some point while doing this in a cramped space I think I may have pulled or bent one of the plugs out of the chassis, because the next time I turned it on to test I got vertical collapse!

That is the deflection yoke connector. There are four wires - two for the horizontal winding, two for the vertical winding. Reverse the polarity of one pair, and you flip the image along that axis. Whatever you do, don't mix the horizontal and vertical pairs!

Hopefully all you did is crack the solder joint at the bottom of the pin, or not get one of the wires attached correctly. If you somehow connected horizontal wires to the vertical or vice versa, you may have blown the vertical output transistors or burned up the yoke. Use your meter to check the yoke, and verify that the wires are connected securely to their proper pins. Also, check for a cracked solder joint on the yoke connector - it's a very common problem, especially if you were just pushing on it.

-Ian
 
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