Hi tmwsiy17:
Your problem sounds very similar to a problem I had with my EP350. It would play for a few seconds and then drop out. I called axiom and they immediately sent out a new amplifier unit for the EP-350. I had to remove a few screws from the back of the sub and swap out the old amplifier unit. As I was doing this a noticed that the wire connector was a little loose. To this day, I wonder if all that was needed was to tighten the wire connectors. My theory is that the sub was coming on and when it vibrated the wires they lost contact. I will never know for sure because by the time I thought of this, I had all ready removed the wires.
Anyway, it may be worth checking the connectors inside the EP500. There are several screws on the back of the sub that have to be removed in order to get to the connector. You may want to call Axiom first, esspecially if you don't feel comfortable taking those screws out.
I hope this helps.
