pelenor

I have a problem with my Pioneer reciever. I had it unhooked for the last couple of months and recently reconnected my Home theater. The problem is that as soon as I turn it on, and pressed for DTS, a popping sound started coming from the speakers. I ommediatley turned it off so I wouldn't blow my speakers. The funny thing is, the VCR and DVD player were not turned on. Before I disconnected it, I didn't have this problem. ANybody have any idea what it could be? Did my reciever have a short?