I have the same problem with my SC-815, especially bad in the winter. Initially thought it might be the FM antenna amplifier (used in wagons), but that was not the problem. Make sure you have the radio code. I pulled it out with the power on (with no FM working) and wiggled the antenna connection in the rear of the radio and it started working. My guess is there is an open circuit in the FM section of the radio circuit board. I have sucessfully opened up this unit, and removed the CD player and the cassette mechanism, to fish out some coins the previous owners children were putting into the slots. I made $.67 in change. I thought that might be the problem but it still cuts out. I'm going to try to find the open in the FM section, or maybe it's right where the antenna plugs in. The circuit board for the FM section is in the rear, behind the cooling fin for the amplifier section. Not easy to get to. I think it is in the circuit for the FM because the AM seems to work, so it shouldn't be the antenna cable/connection. As others have said, you can always find one on ebay, but you might get a bad unit there too. I like to punish myself, so I try fixing everything first. Keep checking this thread for updates when I get to checking this out.