I didn't say fix the monitor because I don't think the poster really wants to do that. He wants a Mame cabinet. If he wanted to fix his monitor he would have joined an arcade group and asked about fixing his monitor, instead he joined a Mame cabinet group. That says a lot.
Monitor can be made right for sure, that is just a matter of money.
I didn't feel any need to mention monitor repair safety both because it is stupidly overblown* in the BYOAC side of the community and because he would get that knowledge anywhere he looked to learn about repairing his own anyway.
*BYOAC/Mame people are constantly giving bad, bad advise about monitor safety. Advising people to discharge monitors in dozens of situations where it is not only unnecessary, but actually creates a risk where one previously didn't exist before. Also, out of many hundreds of monitors dealt with, I have never been shocked discharging, installing, or uninstalling a monitor. It has always been doing adjustments to a running monitor, or G07 filter caps that still held a charge because of a blown fuse. Had the anode come off a Vector monitor once while I had my hand back there with the monitor on, I did not die, but I was unhappy for a little bit!