25" K7000 Pinched on right side (linearity issue)

[duffcon]

I've been working on this issue over on KLOV, but I thought someone here might also be able to help:

https://forums.arcade-museum.com/threads/k7000-pinched-on-the-right.487185/

In Short, you can see the right side of the screen is narrower than the left (look at the MK symbols). I'll try to sum up what has been tried:

All new caps from arcadepartsandrepair.com
new flyback
Different Tube
Different width caps (c 38 @ 2x .39uf and .33uf
New linearity coill (L2)
Checked r99 & 98 out of circuit, both read 2.2k ohms (correct)

Other suggestions:

check d15 & 18
perhaps aftermarket flyback causing issues?

Any other ideas?

 

[DC_CandyCabs]

Following. I have this exact issue on a Makvision monitor I picked up some time ago. Initially, I was thinking of pushing the neck board closer in the affected area but I don't believe it worked to my satisfaction.

 

[arcadeaction]

Do you have another tube to try it on to isolate it? My first suggestion was going to be to try a different width cap as that can cause issues like that.

 

[duffcon]

Do you have another tube to try it on to isolate it? My first suggestion was going to be to try a different width cap as that can cause issues like that.

Yes, tried it in another tube; same issue.

 

[nem]

You need to look for S-correction and S-capacitor. Google came up short for me for the K7000, though.

Following. I have this exact issue on a Makvision monitor I picked up some time ago.

Which Makvision? Makvisions are Wei-Yas, and there's this for C3129D:

https://wiki.arcadeotaku.com/w/Rodotron_666

See 'Side Compression in 15KHz'.

 

[DC_CandyCabs]

You need to look for S-correction and S-capacitor. Google came up short for me for the K7000, though.



Which Makvision? Makvisions are Wei-Yas, and there's this for C3129D:

https://wiki.arcadeotaku.com/w/Rodotron_666

See 'Side Compression in 15KHz'.

Its a M3129DB1 Wei-Yas chassis in the Makvision tube. Ill check that info out, thanks!

 

[RealMFnG]

Change the voltage regulator.

 

[duffcon]

Change the voltage regulator.

Which one, VR4?

It occurred to me that the replacement hot was from a eBay seller. It’s a us seller with a good history so I don’t think it was fake, but maybe slightly different?

I spoke with Randy Fromm and he asked me to check the HOT to see if it was, well; hot.

So measuring 2 k7000s, on for about 20 mins. The faulty chassis is noticeably hotter on the heat sink right above the hot. Measuring with my thermal gun, pointed at the hot, it’s about a 25 degree (f) difference -

132 Vs 105 degrees.

Randy seems to think it has to do with the power supplied to the HOT, suspecting either leaky D15 & 18, or perhaps related to C36, 37, 69. I ordered all the above, first trying the Diodes, then the caps.