Blown something? No amplification?

If you hear a faint sound I doubt if a fuse is blown?? never Know though. You have to have and know how to use a DVM or muti-meter to trouble shoot solid state electronics, as well as know how to solder and check transistors and other electronic parts. There wouldnt be one particular thing that could cause your problem. There could be a several things wrong as transistors and ICs tend to snowball and short out or open up with power surges. If you want , first get a schematic, but if you dont know how to read one stop right here and save your money and upgrade to a shiney new stereo system.. Good Luck