K7000 - No Brightness After Cap Kit/No H.Size Adjustment

zenomorp

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K7000 - No Brightness After Cap Kit/No H.Size Adjustment

Hey guys. I have a K7000 that was working fine and after cap kit/new flyback, I have no brightness adjustment or horizontal size adjustment. I have verified the coil is good and the brightness pot/wiring is good, so I'm left with whatever component(s) that's causing the issues.

I have gone through and re-flowed everything I disturbed and double checked all the positions of the replaced caps. All are good. It was suggested to me that C12 would cause no brightness adjustment if installed backwards, but it's not. If I turn the brightness pot all the way down, the image gets VERY SLIGHTLY brighter. If I turn it all the way up, that little bit goes away. The pot has full range readings and is the correct pot for the K7000 as it worked before the cap kit/new fly.

With the H.Coil in the circuit, I have ran it through it's full range and I get no movement. Out of the circuit, it reads fine. No clue on that.


Any ideas????
 
Is it one of the ones with the remote board, that you can install backwards? If you do it reverses the 'black control' and some of the horizontal and vertical pots.
 
No. All the other pots work correctly as advertised. The Brightness pot is the only one not working.
 
just for giggles post some high res pics of the underside of the chassis so we can see your solder work around the brightness pot.

also i would test C13 and Q8 out of circuit. then if that did not fix it i would sub out IC 1.

i just fixed another chassis with a similar issue with the V-POS Q9 was open.
replaced it and had my adjustment back.

Peace
Buffett
 
Are you sure the flyback isn't faulty? I had gotten a brand new flyback that was faulty from the factory. It's very much possible.
 
Ok, re-flowed everything. Nothing. Replaced C12, C13, and Q8. Nothing. Removed brightness pot, verified it has full operational range and installed directly onto the chassis. Nothing. Check all traces. All traces good. Still no ability to H. Width either. Looks like I'll be sending another chassis to the infamous Arcade Buffett!
 
sweet i will get to unravel this mystery.

Ok, re-flowed everything. Nothing. Replaced C12, C13, and Q8. Nothing. Removed brightness pot, verified it has full operational range and installed directly onto the chassis. Nothing. Check all traces. All traces good. Still no ability to H. Width either. Looks like I'll be sending another chassis to the infamous Arcade Buffett!


sweet i will get to unravel this mystery.


Peace
Buffett
 
wow i think you have become the go to k7000 repair dude. Good for you man, once you get it figured out its easy most of the time.
 
wow i think you have become the go to k7000 repair dude. Good for you man, once you get it figured out its easy most of the time.

yup i think that has happened:)

i get the stumpers and help everybody else get theirs going.

i will update this thread when i get it fixed after MAGfest.

Peace
Buffett
 
I'm starting to think that it MIGHT be a flyback issue because when I turn it up until I get the raster lines, they aren't normal looking lines. Instead of slightly angled, thin raster lines, they are precisely horizontal, thicker, and closer together than normal raster lines.
 
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