So...
1.) The sub stops working intermittently, but the speakers play normal all the time?
2.) Are you completely sure that the three mandatory connections on your amplifier are solid? Ground, power, and remote?
3.) Is the amplifier showing any signs of abuse when it shuts off? Examples being an "Overcurrent", "Impedance", or "Thermal" warning lighting up.
4.) Impedance: What is your amplifier stable to? What do you have it wired to?
Explain the problem a bit better and you'll receive the answers you seek.
