WTF?!? Did I just F up the shadow mask?

modessitt

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Got a game done. Picture looked great. Had it on while stapling in the new cardboard bezel. On the last staple, the stapler knocked against the front of the tube on the rebound - albeit not excessively hard in my opinion. At that same moment, the picture went super bright and blurry. I can turn the brightness down on the flyback for the most part, but the focus will NOT dial in.

I thought to throw my rejuvenator on it to see if it showed anything, but I left the proper adapter at work and can't check that until tomorrow.

So - did I fuck up and knock the shadow mask around? Never had that happen before, but I'm at a loss as to what happened.

I guess I'm glad I have a couple TV's lying around I can swap tubes from, but I'd rather not...
 
That would be a first. Id more suspect you knocked some krap back into the guns or theres some other chassis issue etc.


I have seen a bent shadow mask before, but it was on a makvision monitor that had to have been dropped 6 feet by fedex
 
a bad shadow mask will look like really bad convergence since the guns cant hit the hole in the screen....kinda like a rainbow coloring around the face of the tube....is that what you have?
 
a bad shadow mask will look like really bad convergence since the guns cant hit the hole in the screen....kinda like a rainbow coloring around the face of the tube....is that what you have?

I'd have to snap a pic. It got really bright with retrace, and had a little warp on one side. Once I turned the brightness down, everything was fuzzy, like the focus and contrast were up too high. Focus could get better or worse, but the best was still really blurry.

I'm going to try the rejuv tomorrow and we'll see. I tried banging the tube with my fist, and shaking the game to see if it changed anything, and it didn't.

I'm taking a tube for swapping just in case....
 
I would put it on the rejuvenator. I think you probably just knocked some loose crap down into the guns. Could be maybe you jarred a cold solder joint on the neckboard or main board too.

Shadow mask problems look like bad convergence, not brightness/contrast problems.
 
Well, it's not the shadow mask, but it's definitely the tube. I turned it on and it was still bad, so i turned it off and rejuved it. No real issues. Focus test said good. Turned it back on and it was still bad - maybe worse. Left it on for a bit while I went to find something, and when I came back the picture was nice and crisp. Started playing a game and halfway through it went bad again.

So - I decided to try a few other things before swapping the entire tube. Swapped the neckboard just in case it was a socket issue - no change. Swapped the flyback (again) since adjusting the focus in one direction made the screen brighter and in the other direction made it darker - no change. It would sometimes look okay and sometimes not.

So, I pulled the tube out of the Symphonic TV I'd brought along, changed the yoke and degauss connectors to match the K7000 chassis (yoke was compatible), and now I have a perfect burn-free pic that is holding up just fine...
 
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