Peavey 600F mixer amp problem

[DKAM]

I turned this on recently, the speakers did their usual little "pop", but there's no sound. It's connected to the audio outputs of my Dish box, a synthesizer, and guitar. It has power, and the fan runs. If I crank the volume on the synth and on the channels it's plugged into, the LED next to the reverb/delay switch lights up, and i can hear, though very faintly, sound from the speaker. I found two fuses on a circuit board and they're ok. I didn't check for more, as I didn't want to dismantle it any further at the time. I'm hoping to God there are, and that's all it is. Any help would be appreciated. Thanks.

[Gtr_tech]

Prolly oxidised patch jacks. I don't remember what they're marked....maybe preamp out and pwr amp in. Patch a cable from one to the other. If you get output then the jacks need to be cleaned.

[DKAM]

If you mean plug the MAIN/MONITOR outputs on the front to the POWER AMP IN's I tried that. I really appreciate the suggestion.