It's more likely to be a fuse that's gone. If so it could be caused by faulty device on the heat sink. The only device that converts power is a Transformer. You can test this by simply putting a Volt meter on it's terminals. They are not hard to fit, however they have to be replaced by the same thing or one approved by Rotel.
If you stored it in an area with high moisture content it is probably corroded at most of the contact switches. Capacitors also hate moisture, especially paper capacitors! The tuner is also probably oxidized inside. Now is the time to be brave and pull it apart, but first PULL OUT THE PLUG from the wall. Have at it with electric parts cleaner spray and clean, dry compressed air. If you believe that just because you stored it in your house, there was no moisture, think again! Radios like cars do not do well in storage unless you take precautions to protect them!
there would be life in the old girl it just depends how much you love her and how much you are willing to spend to get her fixed ?? some old rotels are still fetching good money so it might be worthwhile getting a quote