Not Working???

There is a part that has a bad connection or a driver is breaking down. Now that you have no sound could be a short in the output stage of the power amp, or perhaps a problem in the main power supply of the unit. Looking at the circuit board will not give you a sign on where the problem is. Yes in some cases you can see a bad part because the part will burn or overheat. Not in all cases do you get this with solid state electronics. these unbits have no user replaceable parts inside of them. You will need to have this unit serviced by a pro or replace it. This is kinda like when your check engine light comes on and the owner will open the hood to check out the engine? What is he/she looking for? LOL1 Good Luck with this repair.