Audio Systems: can my head unit be fixed?, autowrecking, pioneer dehp7700mp

Question
i recently purchased a pioneer dehp7700mp head unit and installed it in my 94 mustang with no problems. i used all 3 pre outs, 2 going to the speaker amp and 1 to the subs obviously. i recently removed all the amps and the sub from the car as i am in the process of selling it. i disconnected the preamps and wired the the headunit speaker harness correctly, i believe... anyways i reconnected the battery and turned the car on. the headunit got power and i heard a slight turn on thump in the rear speakers but other than that, nothing. i assume the unit is blown, tho i wonder putting an amp back in and using the preamps would be a fix? also the unit is still under warranty, how would i go about getting pioneer to repair or replace it and how long does this usually take?

thank you

Answer
Pioneer's warranty has always been good, if a little slow in turnaround. If you are selling the car, and want the deck fixed, you'll have to find a stock deck to put back in. Shouldn't be too hard at a large autowrecking yard. Mustang stereos were similar to other Ford products, but with special mounting.