Vintage Synth Repair

Hi. I've been trying to get as much info on this problem as I can, and so far no luck. I've had many synths and am always trying out something new. This time it's a Peavey DPM2 61-key synth. Sure, sure. I know the reputation of these. They had their bugs and also some percs which recruited a cult-following as well. Mine was working fine when I got it through the mail from an Ebay sale...and 10 minutes later the outs started crackling and hissing/ Seconds later the sound died and that was that. Everything else works on this keyboard...but now no sound. Can anyone offer any insight as to what might have happened? I know the D/A converters tend to blow on synths from time to time. I've had synths open before and have done some of my own repairs, but this one is a first for me. Can anyone help?

Thanks! 

P.S. The seller was nice enough to offer me either a full refund with return OR 1/2 refund and let me keep it. I took the latter option. I really like the feel of the Peaveys(this is my 2nd), and to me the sounds aren't half bad at all - kind of unique and out of the mainstream.