My xls 602 quit on me at an outdoor gig. It was powering the main tops in stereo--each side had a jbl soundfactor 1-15 and a yamaha club 4 series 1-15, so we are looking at 4 ohms per side. (my CE 2000 was powering the main subs, and my xls 202 powered the monitors)
I had just gotten it all set up, and was soundchecking the first band, around 11:45 am, temperature could not have been more than 70 or so. The main out faders on my mackie board are up to about 50%, and the individual channels up to about 25%.
Brought up the mandolin, added the guitar, added the bass, and everything is fine. As soon as I bring up the drums & he hits the kick, the mains instantly quit on me.
The fault light was on, so I tried shutting down & re-starting. Same result. Then I saw that one of the two fans was not working. So I replaced the amp with a spare to get through the day.
When I got home & checked the amp, both channels worked fine.
I couldn't REALLY test it indoors in a small room because I won't get many more gigs if I go deaf. But I noticed the fan still wasn't spinning, so I am wondering if it faulted due to heat. The rack case was in the sun, but nothing was warm to the touch at the time--and my other Crowns never blinked all day, sitting in that same rack through the heat of the afternoon.
I know that some Crowns have fans that only come on as needed, & others run continuously, so I am not sure if the fan is the problem or if I am looking at something more serious. Electicity was coming from a gas powered generator supplied by the city. Don't have any specs on that, but I can say that it was a LOT more heavy duty than the one I had run the whole system on two weeks before with no trouble.
I have limited electronics background, and feel comfortable replacing the fan if that is all it needs, but don't have the gear or knowhow to check for faulty electronic parts.