K7000 Partial Vertical Collapse

zenomorp

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Ok. I have been through the Sticky and associated threads and I can't find anything that can lead me to a repair. I have done a cap kit and checked all the appropriate diodes and resistors and they all check good.

The monitor starts off full screen, but has a squished top area as if the 50-60hz pot need to be adjusted but I can't make it go away. Here's is how it looks upon power up...


SAM_1990.jpg


SAM_1991.jpg


SAM_1992.jpg



But within a few minutes, it starts doing this...


SAM_1987.jpg


SAM_1988.jpg



I have checked for cracked pots too but they are all good. No matter what I do, I can not get the screen to fill without having the top being messed up, regardless of the fact that after a few minutes, it goes into partial collapse. I have checked D13 and R80. Both good.
 
have you replaced the fly.

looks like it could be cold solder as well.

also check and clean the anode cup and hole.

Peace
Buffett
 
have you replaced the fly.

looks like it could be cold solder as well.

also check and clean the anode cup and hole.

Peace
Buffett


I have a brand new fly, but I was planning on using it on another K7000. I guess I could install in on this problematic one and if it does not fix the issue, I'll reinstall it on the one I originally planned to install it on.

I'll re-flow everything on the chassis and see what happens. Thanks.
 
if it does fix the issue install the old fly on another chassis to see if it was the problem.
that info would be great to add to the sticky if it was the problem.

Peace
Buffett
 
what does the 24vdc look like when you first turn it on and after the screen starts to collapse?
 
Check the vertical size pot. If you have a remote, check the cable, and the solder to both ends. I had this happen once and it was bad solder on the remote cable connection...
 
Check the vertical size pot. If you have a remote, check the cable, and the solder to both ends. I had this happen once and it was bad solder on the remote cable connection...

The vertical size pot works perfectly through the full range. The distortion at the top of the screen gets worse the more I adjust the vertical size.
 
Update. Re-flowed EVERY pad and installed a new flyback. No joy. I'm going to change the IC2 and IC3.
 
yeah that isnt a flyback issue man thats gotta be something to do with the vertical ic or something associated with it. The fact it changes once hot screams bad solder joint or ot of spec resistor but anything is possible. Thats definately a weired one..


BUT.. it works, so the battle is already half-won.

Have you tried hooking up a different games video inut just to make sure its an issue internal to the monitor?
 
yeah that isnt a flyback issue man thats gotta be something to do with the vertical ic or something associated with it. The fact it changes once hot screams bad solder joint or ot of spec resistor but anything is possible. Thats definately a weired one..


BUT.. it works, so the battle is already half-won.

Have you tried hooking up a different games video input just to make sure its an issue internal to the monitor?

Yeah. I've tried MK1, MK2, Double Dragon and SFII. They all share the same issue. I just replaced IC2 and the problem remains. Anyone wanna try and fix it for me?
 
I'm willing to pay to have it repaired. I only paid $35 for the thing in the first place, so I'm willing to pay to have it repaired.
 
the chassis has been fixed.

update this chassis has been fixed.

i installed the additional caps that don't come in a kit.

it has one of the optional mod pincushion boards on it that wells added later with no documentation.

re flowed parts of the chassis and neck board that had not been touched up yet.

then on closer inspection of the neck board i noticed the ring that goes around the neck socket had come half way out of the groove it sits in.

i pushed it back into the grove and fired up the chassis. had a out of adjusted pic.

after adjusting it a bit with the 50/60htz pot and others i had a excellent looking pic.

i let it run for over 2 hours with no issues.

packed it up and out it went back to zenomorp.

cadillacman please add this fix to the sticky in case other have the same problem.

sorry the pic did not turn out better.

Peace
Buffett
 

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i installed the additional caps that don't come in a kit.

What caps would those be? As far as I know, the kits should come with all 17 caps. the only ones missing should be on that pincushion board and maybe the little board mounted on top of the wall for med-res models...
 
What caps would those be? As far as I know, the kits should come with all 17 caps. the only ones missing should be on that pincushion board and maybe the little board mounted on top of the wall for med-res models...

My apologies to bump an old thread, but I'm also curious as to what those additional caps were?
I'm having the same problem with the WG 25K7191 in my MVS.
I just did a standard cap kit and it did not fix this issue.
Any info is appreciated! Thanks
 
My apologies to bump an old thread, but I'm also curious as to what those additional caps were?
I'm having the same problem with the WG 25K7191 in my MVS.
I just did a standard cap kit and it did not fix this issue.
Any info is appreciated! Thanks

sometimes the bi-polars are not included in the kit.
 
Where is a good place to purchase a cap kit, IC chips, and the bi-polars all in one shot for a K7000? I am attempting to repair a vertical collapse, first timer here.
 
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