sounds like one of the capacitors has gone.dont worry they only cost about 60p from maplins.needs to be solderd in.there is earlier posts about this which give good pics and info.sorry cant rememberthe post name but if you type in eurovox capacitor im sure you will find it good luck.
Before going into the caps and so on have you tried to flash your EV, it's not always the case that you need to either jtag or replace the cap. try flashing the box first.