Quoted from jxm1092:because I can now duplicate it if I push both flipper buttons in close proximity of one another
Like dtown I'm looking at 5v.
You will not see it dip unless you have a scope on it. Have you ever recapped the power supply?
ANY machine that is over 30 and has the original caps on the P/S AND shows the problem you are seeing, I wouldn't even pick up my DVM until I've recapped that P/S.