From the pieces that I've taken apart, I don't think I've ever seen a "good" board in a radio or heater or fans or dehumidifiers or other electronic controlled appliance. Sometimes a bigger radio might have a heavy transformer in them or some other copper coils/chokes, but the boards are usually pretty much junk.

Fax machines and the "all in one" type printers (with the scanners built on) sure do have good stuff in them sometimes. Definitely worth a look, IMO.