MMATTS Amp Shuts off

Ok, I just got a call from a buddy and he says he finished hooking up his sub system. 2 12 MMATTS and a MMATTS 500watt amp. All worked when he got it from his brother inlaw. Now he is using 4ga for all power/ground remote to the HU. He says he gets about 30sec and the amp shuts off. No protection and no warning it just shuts off. If he removes the ground and puts it back the amp turns back on. If he removes the main power and puts it back the amp will turn on. Both power/ground steps still results in the amp shutting back down. He talked to another friend that runs a shop and he did not have much time to look at it and said that it all looked fine and did not know what to do. Now, since it is easter I don't have time to go to town and take a look at with a meter. Has anybody ran into an issue like this? If so, please share some quick troubleshooting tips to maybe resolve the issue. Thanks Wade

Measure the voltage across the amp's power/ground terminals.  Double check the ground.  Check the gain.  Check the impedance load connected to the amp and ensure it's within specs.My ex once told me I have a perfect face for radio.