If it turns out not to be the control cable connections the service
manual .pdf is available for download from mods.dk website. Maybe there's a technician or an amateur radio
ham nearby who can make use of it and help.
One of the relays you hear clicking as you change frequencies might be to blame if you're lucky. Find the right one from the manual and very carefully prise or cut open its little casing. Cleaning
the contacts mechanically often saves them.
Sometimes a waterproof seal can fail.
Look carefully all around inside with strong magnification for signs of water
ingress. Doesn't take much to cause failure, look for greenish or whiteish deposits.
A good technician can sometimes save a board by removing affected components and cleaning
beneath. Corroded tracks can often be wired & soldered.