Behringer ep1500 Crackling

[venger]

I've been browsing around a bit trying to determine what might be wrong with my Behringer ep1500, (QSC RMX1450 clone)

I use one for live performance FOH in small bars to drive a pair of Behringer B1520 pro speakers. I usually run them with the gain set to 32.

For several years this worked flawlessly. Then a couple months ago I was asked to run sound for a metal band and the guitars were very loud, and this system could barely keep up just running audio for the vocals. I set the gain to max to get through the show.

The clipping light pulsed frequently, and at the end of the show, the amp was very warm.

Since then it has developed a crackling noise distortion on channel 1, and I have to turn the gain down on that channel to lessen this

Also during that show from hell, one of my speakers were damaged, and I had to replace the horn. I didn't notice the horn was out till a couple weeks later but I think these problems are related.

I used to be an electronics tech years ago but have been out of it a while and have obtained a schematic of the QSC RMX1450. I want to open it up and have a look around to find any obvious damage.

Any hints or suggestions what to check for would be GREATLY appreciated
Thanks in advance

 

[meanman1964]

Here you have the EP1500 schematic

 

[venger]

Thanks for sharing that link