I have a Dewald C800. The AM comes in loud and clear across the entire dial, but the FM band is completely dead. The tubes are still lit, but all I get is a slight hum if I turn the volume up high. I've tried rocking the bandswitch, with no effect. I also tested the 12AL5 tube and it checks out ok. What else should I check. This is my first tube radio with FM so I'm not sure where to look.

Burned coils? Burned resistors? Shorted/leaky condensers? Someone played around with the coil adjustments? Do not assume this until all else has been checked, and do not adjust the coils until after checking them out with a signal generator.

Thomas