GMK-29FS3 intermittent screen shake, both horizontal/vertical at the same time

[yatzr]

I have this monitor from a super neo 29 cab. A couple months ago, I noticed this intermittent screen shake where it's like the overall size of the picture bounces between two sizes. It kinda seems like it stabilizes after it's been on for awhile. I just did a cap kit and that didn't fix it. About to take it out again and check for bad solder joints. Thought I'd post here to see if anyone has good ideas of what else it might be.

Here's a short clip of the screen shake
https://gfycat.com/hardaptcoypu

[grantspain]

it could be a bad solder joint causing momentary voltage loss
I do not think its unstable b+
it could be flyback failing

[yatzr]

I tried reflowing any suspicious looking joints. None of them really looked sketchy though. No change. Trying to source a replacement flyback now.