85 Buick Riv Radio problem

I have a basic Delco Radio (the original in my car)w/o a cassette deck. Sometimes, I turn it on, and it's just fine. Sometimes, all I hear is static (no station on a given frequency). Sometimes, one station comes on all the FM frequencies. Other times, the radio is fine for one moment, and suddenly, it'll cut out or play the one radio station. I'll punch the panel above the radio. Sometimes, that's a temporary fix, other times, I get busted knuckles with a busted radio. Any help, please?