Video Converter problems

[_JMFR]

I've recently restored a Ultimate MK 3 arcade. Its been rewired,installed new buttons,and had the monitor restored. Everything looks and runs great, but whenever im playing,if i hit the buttons to hard,or hit the side of the cabinet, the monitor gets a little fuzzy..i checked all video and power connections and they all seem to be fine. I'm assuming that it has the original video convertor in it. Now my problem is that i know nothing about video convertors.(im sorta of newb) if anyone has some advive on this, or information about them PLEASE let me know!

[grantspain]

bad connection or bad solder joint on the monitor chassis

[Kevin Mullins]

If it's an original MK3 boardset, then I'm not sure what you mean by "video converter".
But it's sounds like a bad connection on the monitor as grantspain mentioned.
Check the focus lead on the neckboard for bad solder joints, wiggle the focus pot on the flyback and see if it's flaky as well.

Point being if you have to "bang" to make it happen ... then something is loose.