common k7000 issues - common repairs

Are your G2 and focus wires connected backwards?
They were 100% not backwards on the old flyback, I checked previous pics that I have.

On the new flyback I hooked the thicker one up to G2 and the thinner one up to focus, so I believe it's correct as well.

Thanks for the idea!
 
Also check continuity from the RGB/s output wires from the jamma edge though the input header on the chassis. I once had a chassis where the input header was so tarnished it was actually creating a ton of resistance which made the image VERY ghostlike. I had to sand the pins down!
 
  • Like
Reactions: KNG
They were 100% not backwards on the old flyback, I checked previous pics that I have.

On the new flyback I hooked the thicker one up to G2 and the thinner one up to focus, so I believe it's correct as well.

Thanks for the idea!
That is backwards. Thin wire is always G2. Thick wire is always focus. There's your issue.
 
"The new flyback has two red wires and the smaller diameter red wire goes to the single pin post on the neck board and the larger diameter red wire goes to the white neck board socket."

https://www.arcadepartsandrepair.co...x0528-001-wells-gardner-k7000-series-flyback/

No?

Thanks!
-Kyle
Yes. Correct. However, you said....

"On the new flyback I hooked the thicker one up to G2 and the thinner one up to focus, so I believe it's correct as well."

That is backwards. Thin goes to G2 and thick goes to neck socket. Just post a picture and we can tell you if it's backwards or not. What you are describing is a classic symptom of having them backwards.
 
Those wires appear to be the same diameter. Never seen that before. What's with the hot glue on the wires and all the splices? You can try swapping the wires. I'm betting that will fix your issue. You won't damage anything by trying. You can just swap them back.
 
The hot glue is just for strain relief. The splices are because I've swapped the old and new flyback so many times.

The red wire is slightly thicker than the gray.

I really don't think this is the issue, however. I had good image, and then I didn't. I think it's some other chassis issue.
 
I just picked up a cab with a k7000 (25") I didn't bothe r plugging it in, I was told the game didnt' work.

So I decide to pull the chassis to recap it and give it a once over. I notice the fuse is blown. It calls for a 2amp sloblo, there is a 1.5amp slo blo in there.

Anyway, I start thinking ok, the HOT or Vr is blown. FLyback looks good. I pull the hot and it tests fine. I tested the legs of the VR in circuit and nothing was shorted, and I don't happen to have that stinking part on hand, so I left it. (STR30130) I think (5 leg, narrow version, I have some STR 30130 that are 4 legs and twice as wide. Anyway, it's been years since I've worked on a k7000.

I did test the safety cap and it was shorted, as well as the cap above it. (I think they are C36, C39). Anyway, after pulling them for testing the top cap was not shorted, but the safety cap was. So I replaced it, reinstalled 2 working caps, now no more short.

My question is not, should I just plug her in? I have hundred and hundreds of fuses. This is my last 2amp SB that I have on hand, lol. the previous owner did cap it, and ........it looks like they changed both the HOT and VR, so maybe I'm good, it was just the safety cap blowing the fuse?
 
Quick story: spent like 6 hours troubleshooting a new to me 25" k7000 that I just rebuilt. The issue was the picture size was about 40% too small. I ran through hours of @zenomorp university, and combed through all my notes and tons of threads here to no avail. Unlike other partial collapse issues I've had, the picture was perfect, all adjustments worked - it was just too small even with the size pot maxed out.

I use a 25" TV as a test tube and I remembered that the vertical winding on the tv yoke is a bit low at 7ohms. It's never been an issue, but for some reason this particular k7000 doesn't like it. I popped it onto a legit k7000 tube (10 ohms vertical) and it's perfect 🤪

Good lesson to remember the simple stuff.
 
Last edited:

Putting this here for information that I had to figure out. I have 2 25" K7000s (1986 revision) that have the 4 legged cap present at c36. One was complete, one was missing c36 & c38.

The board that was complete has C37. C38 was mounted near the yoke header instead of D18, which was mounted on the underside of the board.

The board with the missing c36 did not have a c37, but had a jumper instead. I spent a lot of time wondering how to go about replacing these caps with the 2 leg mod as I wasn't sure that the 2 legs closest to the heat sync needed to be joined. The chassis did not power up without it at all, totally dead. Watching @zenomorp 's video above I can see the chassis here is the same layout with the 4 legged c69 and a c36 in parallel on the bottom. I placed a C36 & C69 in place and joined the legs on both sides with a jumper. Fired right up, no problems except that the screen had a slight 'flicker' where it would dim intermittently. It really felt like a bad brightness or contrast pot, but neither helped. I tried the normal stuff, checking and reflowing, even replacing IC4 as the B+ was slightly low at 129, but that also didn't help. It really felt like an "analog" issue, the only control left was on the screen pot on the flyback. Given this one was toward the end of the focus adjustment range, I swapped it out and bingo! Perfect image.

Thanks again Mike, your stuff is invaluable to this community! I hope this post helps someone.

1731022892393.png
 
Need some help with some diagonal bars scrolling through the picture. The bars are faint. Also the top edge (horizontal) is quivering slightly. The chassis was capped plus a filter cap installed. B+ reads about 122.
 
Need some help with some diagonal bars scrolling through the picture. The bars are faint. Also the top edge (horizontal) is quivering slightly. The chassis was capped plus a filter cap installed. B+ reads about 122.
19" or 25"?
 
Start a thread in the monitor forum with pictures of the issue and chassis, this thread is more of a "this is how i fixed this issue" thing.
 
Back
Top Bottom