as above, they just go out over time. and shipping is not your friend with some electronics.
Don't know your exact situation, but you can always go aftermarket. can be done fairly inexpensive depending on what you want out of it. and this can give you more capabilities like aux in, ipod, usb, BT. . .
2010 Volvo C70
2011 Harley FLHTK
Midwest Crew #22