Response from Tim: Always start simple follow the cord from the wall and see if there are any fuses in the bottom of the game perhaps one of them is blown. Its probably not your isolation transformer because that only goes to your monitor and you would see some othere signs of life like the marquee or coin lights on. It could very well be your power supply so you will need to get a multi meter and check it out.
here is a video a couple of vidoes that might help you out that we did.

Good luck with your game keep us informed
Tim