Count the beeps. It emits those beeps and boops in test mode to indicate working/not working RAM chips.
The pattern is such:
If you hear a high beep at-
1st - Bad Ram at P4
2nd - Bad Ram at N4
3rd - Bad Ram at M4
4th - Bad Ram at L4
5th - Bad Ram at K4
6th - Bad Ram at J4
7th - Bad Ram at H4
8th - Bad Ram at F4
It will do 8 beeps then try to boot into test mode. If it fails it'll just restart. You can also use these to find what art of the board is not working correctly.
It's very common for these to die even on boards without issues. I've replaced 6/8 of my RAM chips on my Missile Command upright and it was almost a yearly tradition. Works great when I put it away for the winter. Then I bring it back out for summer and it's broken again. You could always try to find someone local with a Missile Command to test the board. It honestly sounds like bad ram chips to me though.
Is it doing something similar to this? https://www.youtube.com/watch?v=o93RUUwQf5M
Ah yes.. it looks like from the video it is exhibiting the same or very similar issues as my two boards are showing. I think you guys are spot on about that. Time to break out the testings tools. Thanks guys, will let you know what i find out.

