I looked for this problem all over the web to no avail. The fans and lights inside the amp come on but the blue lights don't. They flash for a millisecond when the power to the amp is cut and everything else goes off. This started happening randomly and still happens randomly. The amp comes on and works normally maybe 1 time out of 3 since last week. Sigh.

 

I'll assume your power and ground are good and solid, but double-check them. There may be enough to power the fan, but not the actual amp.

Disconnect the woofer and see if the blue lights come on. If it powers up consistently, attach a different woofer and check again. If this works, you've got bad speakers.

If it fails to power up even without a woofer attached, and if it's under warranty, send for repairs, otherwise you may still want to send it for repairs, depending on cost.

 

I'm going to assume you have the power line fused if not wtg. Otherwise do what's already been said if non work I have a feeling it may have been shorted out and some internal parts are crispy. You could open it up and verify unconnected of course and you could sniff the crap out of it before doing so to see if there are any burn odors

 

I'd chalk it up to shotty build quality. I have had Phoenix amps before and I was not running anything crazy or coming close to maxing the damn thing and it burnt out. I used JL amps and never had a problem. I have a set of Alpines that I am gonna use in my coupe this time...personally if I were you, I'd just get a new amp with a little more reliability. Again this is all from my experience with that brand...good luck