This happened to my gt1000 like two weeks ago, was fine the day before but then the next day, no lights or fan, just click click click.FWIW, I've been using a GT800FX to power stage cabs for several years with no issues.
Last week at gig, the Amp failed. No lights or power, just a steady clicking.
Opened up next day, same thing. A light inside was blinking on/off along with the clicking.
It's at repair shop now for evaluation. Other than this, never had a problem before.
Mostly used to power a 2x12 stereo Cab for stage use.