No sound out of head unit

I currently have a sony head unit in my car with a amp hooked up 2 it with a sub runnin of da amp. My mate was muckin round with da amp the other day and stupidly connected the head units right rear speaker output wires on2 1 of the amps channels. He disconnected the sub first. There was some beeping noises when he switched the ignition on and now no music will play out of the head unit. When i connect the sub back on the sub goes but no other sound comes out of speakers. And also when i connect the speakers on2 the amp the speakers go. Has  something happened 2 the headunit??? Can any1 tell me what is wrong ??? Th e wiring is the exact same as when everything was runnin perfectly!!

for the money you will spend to repair it you could buy a new deck or close to it. the only real way to find out is to take it to a repair shop and let them give you a qoute.

for the do it yourselfer it would not be practical or physiclly possible.

you can try , but they can tell if it has been shorted out and might not cover it.

and yes it is the ic mosfet on the main board and some resistors and diodes.

In the future please remember that you are speaking to the world. Try and use correct grammer and spelling please. Some of us are either (too old) or (don't care) when we see posts worded like this. It is not that we do not want to help, but what is best for the forum and the people who read and visit here needs to be considered.