Hi Arthur, Whenever I find a problem with any radio, particularly if it hasn't been used in a while, I shut off the radio and exercise the rotary switches. In the case of the FRG-7 I would start off by rotating the band and mode switch 20 times end to end. This will wipe of any oxidation from the rotary contacts. If it seems to improve the problems then do it again one more time. If it works then all is well. If it comes back again try some dexoxit on the band switch contacts. Use dexoxit by applying it sparingly to the rotary contacts.
If the above doesn't work then some alignment &/or troubleshooting may be required.
73
Roger VE7LB