25K7000 with multiple issues

Peale

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I have a batch of 25K7000 from a client that require repair. Almost all of them have been BADLY hacked.

This one, in particular, has me scratching my head.

1) fired it up, before doing work. Noted presence of black "blob" on side of screen. I can get it to nearly disappear by adjusting vsync, but not entirely.

2) cap it. Lots of solder rework. Colours are better, but the black blob remains.

3) for giggles, replace the flyback. Blob issue remains, but appears to be not as severe.

4) while going over the chassis for abnormalities, I note that the 4th wire on P202 has been cut out. I can't seem to find any technical docs on why removing that might be a good idea, so I'm just about to replace the assembly with one from a donor chassis. If I've traced the neckboard correctly, this may help with the blue that appears to be nearly completely on, all the time.

5) shrinking the picture makes the blob get much bigger.

I suppose one of my next moves is to replace the vertical IC.
 
man thats weired. If you get time post some pics. I honestly dont have a clue, id be trying ics too.. you sure the tube youre using for testing is good?

best of luck. It amazes me how many different failures these damn k7000s get.
 
man thats weired. If you get time post some pics. I honestly dont have a clue, id be trying ics too.. you sure the tube youre using for testing is good?

best of luck. It amazes me how many different failures these damn k7000s get.

Tube better be fine, it's my test tube. :) I use it on all my 25k7000s. Hasn't let me down yet.
 
Ha!

Your working on the same clients hacked chassis as I am.. I've got 2-3 k7000 25" chassis here that have good o'l P&L's tag on them.. Looks like they replaced half the caps and installed faulty flybacks as they all have big holes in them..

I've had some luck fixing his stuff.. Lots of cold solder joints, wrong trannies on neck, and just bad work..

Good luck man.. If you do need another 25" tube, I have a few donor tv tubes that are drop in matches for k7000. Just installed one in nerdygirls monitor.. Looks brand new!!
 
Your working on the same clients hacked chassis as I am.. I've got 2-3 k7000 25" chassis here that have good o'l P&L's tag on them.. Looks like they replaced half the caps and installed faulty flybacks as they all have big holes in them..

I've had some luck fixing his stuff.. Lots of cold solder joints, wrong trannies on neck, and just bad work..

Good luck man.. If you do need another 25" tube, I have a few donor tv tubes that are drop in matches for k7000. Just installed one in nerdygirls monitor.. Looks brand new!!

PNL is garbage. they're probably the reason one of my Polos isn't right. and a D9200 I had done by them. sent it to them saying the flyback arced, they never changed it. they did a couple color transistors and skipped the 3rd one. low and behold when the warranty ran out, the 3rd one took a shit. that's when I learned how to do it all myself. this was long before I knew about arcadecup or how to fix shit on my own. lol

I seem to recall someone else posting a monitor on here with a strange black blob in the lower left corner.. I think someone said maybe the mask was bad on the tube?
 
I seem to recall someone else posting a monitor on here with a strange black blob in the lower left corner.. I think someone said maybe the mask was bad on the tube?

The tube is fine! :) Really. It's my test tube. If it were bad, then it would be bad on ALL of them.
 
As for flybacks, I've replaced three out of five of these so far. One of the "repairs" was a little bit of silicone to reseal it. Two were cracked, one was seriously arcing.

And the guy asked me to not replace as many as I could, so he could "milk" them along. Dude...penny wise, pound foolish.
 
I know you did a cap kit and whatnot, but did you replace the main filter cap? (C55 IIRC)
Also double check C57 and that general voltage regulation area. (test the new cap, traces, etc)
 
I know you did a cap kit and whatnot, but did you replace the main filter cap? (C55 IIRC)
Also double check C57 and that general voltage regulation area. (test the new cap, traces, etc)

As stated before - I replaced ALL caps. :D All cap jobs I do, on a monitor of this vintage, I replace them all.

I've been going over this with a fine toothed comb. So far, I haven't found anything unusual. Still haven't replaced the vertical IC because I have to remove it from a parts chassis. I moved on to another chassis in the interim.
 
Swap the neckboard with another to see if it changes. That way I can concentrate my comments where they belong...
 
Anytime

You got it man.. NerdyGirl came by to pick up her (2) 25" k7000s I rebuilt for her today.. Tossed in a donor 25" burn free newer monitor.. Man, it's like new! She was super excited to install it in her neo geo..

I really need to take pics of an original tube hooked up, and a donor tube.. The picture is sooooooo much better.
 
My test bench 25K7000 tube is a donor. I wasn't sure if the original was working (and it had a lot of burn) so I swapped it.
 
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