quick question about recapping a k7500 and if I have to change the flyback

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quick question about recapping a k7500 and if I have to change the flyback

Is it an automatic change like when you recap a g07? Or does it come down to the color knobs on the fly that makes the decision for you?

I don't ahve this monitor in front of me yet, but I looked at it today, and the chassis looks brand new.

I may not even recap it until I get it home and see how it acts. The guy says it gets "foggy" looking after being on for a half hour or so. I'm gonna get the tube on the rejuvenater before I do anything else, but I want to be prepared to do anything I may need to.
 
They usually need changed. They have focus drift problems and usually have cracks around the pots. I sell flybacks on ebay and the K7500 is my biggest seller.
 
Yeah, foggy (out of focus drift) is what I've seen with most k7500s. I've also seen a few people deal with it and adjust them constantly cause they don't feel like changing out the fly.. 2 of these guys (one and op) had the flyback detonate and covered the chassis in goo.. I've got pics.. Then a simple job became a multi component change..

So yeah, replace every k7500 flyback you run into. Make sure to mark or photograph the back wire that wraps around the core of fly.. If you put it back on wrong, you'll get a black bar down the right or left side of your monitor.. I even put one back exactly back where it was and had this issue. So leave one end unsoldered, use an alligator clip to figure the best placement.. If I'd know this it would have saved me hours of pulling my hair out :(
 
I'll be the dissenter. I only change the flyback if it has cracks around the knobs or has already blown up - or has some other symptom of a flyback issue and I've already recapped it and fixed and bad solder or broken traces ...
 
so I ordered a flyback for this, it's from a golden tee and I measured it at 29" (I think , it was a quick measurement) there is a sticker on it that states it was made in teh year 2000.

Another sticker says only replace with k7500 chassis.


shouldn't be any issue with a standard k7500 flyback huh?
 
it's definitely 29" and here are a couple of pics of the chassis


took them in the dark garage in 'night' mode, so if they aren't very clear, sorry.



looks kind of like a u2000 huh? I can't find a picture of a k7500 to match it to. I guess there are some differences between this chassis and the u2000 pic on bob's site.
 

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Yes, they're very similar. The u2000 (standard res) and u5000 (med res) were the successor to the K7000. Only problem was, they suuuuucked. Horrible design, there were 3 different factory upgrade kits for them released by Wells within like the first year. So Wells knew that they were in deep shit, and redesigned some of the board, and re-released them as the K7400 and K7500. They're a much better design, but still have some quirks.

I never used to replace the flys on these, but unfortunately over the past year it's pretty much gotten to the point that you have to replace all of them. In general they don't go bad per se, they just drift. Some of them do both, the brightness, AND the focus will drift, and not just a litte bit, I mean bad. You can't glue the pot in place either, because it drifts internally no matter where the knob is set. Better to just replace it and get it over with.
 
Oh, and there were also 29" ones believe it or not. Crisis Zone for instance has 29" K7400's... I just replaced the fly in one two days ago, the part number is slightly different but it worked. The last number is a 2 instead of a 1 like usual. 053x-570002 or something like that.
 
Usually k7500 have a red and white wire that connects to a frame mounted tranny.. That's an easy way to figure out what you've got.. Looks like a k7500 to me :)
 
Usually k7500 have a red and white wire that connects to a frame mounted tranny.. That's an easy way to figure out what you've got.. Looks like a k7500 to me :)

thanks guy

yeah I think it's a k7500 as well at this point. I suppose once I start capping it this afternoon I will notice some bad/weird cap locations if it's not.
 
The four different versions - K7400, K7500, U2000, & U5000 - can be identified by where the width coil is located, as well as the P??? number on the chassis and remote (P804 on the remote is a 7500).

That's assuming the sticker is missing on the back left corner that would normally say WGM2775 - for 27" K7500...
 
The four different versions - K7400, K7500, U2000, & U5000 - can be identified by where the width coil is located, as well as the P??? number on the chassis and remote (P804 on the remote is a 7500).

That's assuming the sticker is missing on the back left corner that would normally say WGM2775 - for 27" K7500...

yeah I was basing my observation off of the width coil as well (when I spoke to Bob) about it. The sticker may still be there, lol, I haven't really messed with it yet aside from pulling the chassis. I'm gonna start on it in an hour or so when I get home.
 
ok I am on the neckboard changing caps 2 questions:

C519 there was no cap present but it calls for a 4.7uf 50v There appears to be traces of a cap formerly being there, I see legs still soldered in teh holes. So it either blew or it was removed. I put the proper cap in, is there any reason why I shouldn't?

2. C512 is a microscopic little blue mylar cap with no indication of + or -, it calls to be replaced with a 1uf 50 v. Should I change it or leave it, if I change it which way do I put it in?
 
I'd leave both out, personally. YOu're up and running, so I'd just leave it the way it was. There's so many variations of these things (and yours is a 29", kind of weird) that they likely cut that cap loose on purpose, I've seen some like that too (don't remember if it was the same location, though). The mylar one I'd leave alone too since you can't see which way to put it. If you put it backwards it might fry something, fuck it just leave that thing alone.
 
I'd leave both out, personally. YOu're up and running, so I'd just leave it the way it was. There's so many variations of these things (and yours is a 29", kind of weird) that they likely cut that cap loose on purpose, I've seen some like that too (don't remember if it was the same location, though). The mylar one I'd leave alone too since you can't see which way to put it. If you put it backwards it might fry something, fuck it just leave that thing alone.

good enough answer. The monitor was running with the 'fog' after being on awhile he said, so I will go ahead and yank that cap and leave the one with the small blue mylar alone.
 
anyone have a cap map for a 7500?


There are a couple of locations that are covered in "white cement" of some type that won't scrape off,it was there to help hold some caps in place.

The one in particular I am looking at is C616 (IIRC). It has a 1500uf xxV. It looks like I'm supposed to drop a 2200uf cap in there. With R616 and C615 right near this position, I am deducing that it is in fact Postioin C616, but I'd like to be certain.


OK check that, no cap map needed. I looked at the cap map for the k7400 and got my questions answered about the 2 positions I was curious about.
 
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ok, got her capped, changed the flyback.


plugged it in my superman to test it, got an all black screen. turned up the brightness on the flyback, just had a fuzzy white screen with a big black bar on the left hand side of the screen.



should I test this in another game? does this sound like some problem that one of you have experienced before?
 
By fuzzy, was it just out of focus? You have to readjust the focus of course when you do a new flyback. The black bar could possibly just be the horizontal position is shifted over.

When you did the wire that wraps around the ferrite on the flyback, if you wrap it the wrong way (backwards) it'll make the left side of the screen darker than the right side.
 
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