K7000 chassis worth repairing?

spacemonkey

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Hello, got a 25" tube with a K7000 chassis, the thing is filthy.

So far, fuse is open, HOT is shorted, and it has the flyback with the white knobs. (looks like it is cracked but can't really tell because it is so filthy)

The tube has no burn-in. I am thinking of ordering a cap kit, fuses, HOT, and flyback.

So my question is, should I bother spending time on it? Any suggestions on cleaning the PCB?
Are the replacement flybacks currently available reliable?
 
Definitely worth rebuilding. Good cleaning with either simple green or a dish detergent. Be sure to dry very well. I like to use compressed air. Gets the water out of all of the nooks and crannies.

Security0001 has all the parts you need. Very reliable parts, good prices and great service.

Ed
 
yes if you need parts i have the best quality and all in stock. BTW: you can wash the chassis in the sink or dishwasher like i do because i hate working on filthy parts (just make sure to let dry completely before power up).
 
Well, got my parts, put everything in, checked for bad solder joints, possible bridges, made sure all my caps were in the right way, etc.

Turned it on, high pitched whine, then nothing.

Pulled out the PCB and I see at least the HOT is shorted, fuse is blown.


I ran a search and found this thread;

https://forums.arcade-museum.com/showthread.php?t=397529

Looks like I have a similar problem.

What I replaced so far.

HOT
VR
Electrolytic Capacitors
Flyback

Gonna start testing more parts after I take a little break.
 
you still have a short in the horizontal section if your H.O.T. is blowing.

check all the parts listed in that other thread, that is where you need to start.

if you hit a brick wall, you're welcome to send it in.

let us know you're test results.

Peace
Buffett
 
Thanks for the help everyone, I found that C38 was shorted. I thought I had checked it before, may have missed it.

Got a replacement, got a new VR and HOT, replaced fuse.

I reflowed most of the chassis, got a picture now. It still needs some more work.
There is a curl on the top of the screen that happens with my Neo Geo PCB.
Looks like this is a common problem, doing some more research on that.

Also there is a bloom effect when bright objects show up on screen. The degaussing coil has come off the tube, the zip ties that held it together disintegrated. Need to take care of that.
 
K7000's do bloom on bright screens, watch a video by buffett on adjusting your monitor. They're on youtube just search up buffet monitor adjustment.
 
they will both blow the fuse if shorted.

both are in the Horizontal circuit.

one can be shorted and the other be fine.

Peace
Buffett

Sure. I'm just curious which EXACT one was replaced in this case. As I was assuming one is more to fail, more often, than the other ... :)
 
Sure. I'm just curious which EXACT one was replaced in this case. As I was assuming one is more to fail, more often, than the other ... :)

it would be nice to know.

i would say from what i see, C38 is the more common cap to blow.

it is really about even either way, i just seem to remember more of C38 going.

Peace
Buffett
 
Another update, new C51 and some adjusting got the distortion on the top of the image pretty much gone.
Colors look great, while adjusting drive and cutoff on the neckboard I noticed the pots were really lose specially every cutoff, will get some replacements. re-attached the degauss coil.

The only thing I can't get right is the picture is about 1 inch away from the edge the top and bottom, on the right it is about 1.5", and about .5" off from the left. I'm also getting some fold over on the right side. I suspected the remote board, I resoldered and checked every pot, wiggled it and they all seem fine on my multi-meter. Hor. width coil can only do so much.

I know I can change C38 to a different value, but what concerns me is why is it happening from all sides? May pull the chassis out and look it over tomorrow.
 

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never change the width cap if you haven't capped the whole chassis. did you test the pots to see if they are within spec's? if you need parts i have everything in stock and all the correct fitting/rated pots for the entire chassis.
 
never change the width cap if you haven't capped the whole chassis. did you test the pots to see if they are within spec's? if you need parts i have everything in stock and all the correct fitting/rated pots for the entire chassis.


Hello, ordered most parts from you.

What I replaced so far.

HOT
VR
All electrolytic capacitors
Flyback
C38
C51

Reflowed most of the board, reflowed the remote board, checked pots on remote board.

Need to check the pots on the chassis, since it has a remote board there's only Hor. Hold and the 50-60 pot IIRC.
 
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