Any ideas? Its a siemens lc47650gb, 2 yrs old. The extractor fan has suddenly stopped. Cant hear any buzzing, so dont think its jammed or stuck. Blades turn when pushed by hand. Lights work, so fuse must be OK in plug. Is there another fuse inside the unit anywhere? Or could it be the switches. Hasnt had much use in 2 yrs at all. Help!