Try a few drops of penetrating oil down the shaft of the control. If that does nothing, try holding the soldering iron under the bushing where the shaft goes into the control. If you can get it moving, you may be able to get it freed up and then be able to flush it with a cleaner to make it go again.
Looks like tone switch on the left, volume/power in the middle, band switch on the right, and tuning top center.
If it just will not go, you'll need to replace the control with one that has a power switch and a 250K pot. Matching the shaft up may be the harder part.