Here is whats going on with this machine. Any ideas?

Machine starts and homes fine. Spindle runs fine. Problem occurs while machine running fine and spindle on (but sometimes when spindle off) I can hear the relays in the back trip (usually two loud clicks very close together), the screen goes completely black and machine automatically starts to reboot. This has been an intermittent problem on and off. Some days the machine runs fine. Lately it happened more and more often and now happens all the time, usually between 5 and 30 minutes of run time. Sometimes one click is heard instead of two and the screen gives this message: "GP FAULT FATAL ERROR. MACHINE INTEGRITY NOT COMPROMISED. SOFTWARE WILL TRY TO RESTART TO CLEAR THE ERROR. IF YOU ARE IN MDI SYSTEM WILL TRY TO SAVE CURRENT WORK" and also the message "SYSTEM ERROR POSSIBLE POINTER ERROR"

I took a bunch of videos to help find the problem. Here is a video of inside the back when this occurs. I can clearly see the K1 (I think its a relay) pop out just before K7 pops out / trips. K7 is spindle forward. K6 is spindle reverse. I am assuming K1 is a main voltage feed:
https://youtu.be/4AHsBq1LCIU

I put a voltage meter on the 2 small wires that feed the K1 relay. There is no voltage at all there while machine running but then there are spikes of voltage going to it when it trips and repeats in intervals afterward. I am guessing this is the signal telling the K1 to trip. Here is that video:
https://youtu.be/YSt-mkqf5HQ

Video of front screen when error occurs:
https://youtu.be/fDDJVnnq_Ws

Video of the small LCD on one of the control boxes in the back when error occurs. In this video the spindle is doing 450 rpm in low gear in reverse. One thing the screen says is "UV DC BUS UNDERVOLT" just before it shuts off. Not sure if this is the error code that made the machine trip or the control box telling the reason it is shutting down:
https://youtu.be/TFqAnxhUceQ


Only other piece of info that might be useful:
Moved 2 years ago from shop that had 208 line voltage. Changed wiring on transformer from 208 to 230 but actual line voltage in my shop reads 248v. Did not make any other voltage adjustments. Machine has run ok for the 2 years at this location except for recently.

Thanks so much