Stereo problems

[SILINC3R]

So had a 93 stock radio with the aux input for a while. Loved the fact that it had an aux and that is why I have bought 3 of them to piece together a good one. Well about a month ago it started to slowly cut out randomly. Right before i drove across the country it got pregressively worse. it was like it was nt grounded out and would come on if you hit a bump or as if it had to warm up. through the trip it just stopped working completely. Lights still lit up and the display button worked and would display the time on the LCD if pressed. So the other day I bought a new stereo just incase and yesterday started trying to work on the old. took it out and noticed there was a wire not connected on the speaker side of the 2 plugs. later found out it was the 12V ass wire which I thought would fix the problem. it didnt. red battery wire had 12V, ass had 12V, ground was grounded, illumination had 12V. the one thing i noticed was that when the stock radio was plugged in the 12V ass wires would drop and not read 12V. check every fuse and all were good. decided to install the new radio. ended up not having 2 wires installed. the 2nd ass wire and (-)illumination wire. plugged the harness into the radio and turned the key. success so i plugged my droid into the aux and the power cable into the USB to charge it. thats when it went wrong and stopped working. started flickering and then nothing came back on the display. the 10A fuse in the back is still good so not sure what happened. hoping i didnt fry it somehow. anyone got any ideas? thanks in advance

[Binford]

Make sure speaker wires aren't grounding out, either to themselves or the cars metal. If Aftermarket spkrs are installed there is also a chance they could be shorted there as well, but it sounds to me like wiring issues at the deck.