My son has a Sherwood RX-4103 AM/FM stereo receiver. The fuse blew in it. He replaced it. Now, when he turns it on, the lights come on. It shows the station and all of that, but you can't change the station or turn the volume up. Then, after it is on for about 1 minute, it shuts back off. The fuse is still ok, though. Any ideas of what it could be?