Swinks,
Mate I'd suggest a full going over of the machine before playing it any more or letting kids play.
Was it bought privately or dealer?
Having game reset is not a big issue, lights dimming...Hmm a machine is drawing well less than 10 amps so unless that power circuit in your home is close to capacity I'd suspect another issue.
Wiring hacks on DMD power etc can be fixed and as long as the joints are not just taped over with some cheap arse black tape
they can be repaired properly with heat shrink / solder etc.
Have you got a DMD? I'd just check the Ohms for earth / grounding.
With the game off & unplugged I'd test what ohms you are getting from the earth pin on plug, to various metal points on the machine. I'd start with the power distribution box (volume control area), lock down bar, legs, metal in backbox and finally a ground point on the power board.
Lots and lots of other things to go over, but safety should be number 1.
