Welcome to Beoworld, Chas, and congratulations on your purchase! As the owner of two K's and one M, I can assure that the Beomaster 900 is a must have for every serious addict 😂

Those old potentiometers can indeed get sticky. The knob is held on the shaft by that little screw; if you remove the knob, you can probably spray on the shaft without further dismantling of the unit and with a little luck, it'll start working just fine.

If you need to open the unit, you need to remove the two larger screws on the bottom, the two screws on the middle of the side edges on the back panel, and perhaps four small screws on the top and bottom edges (can't remember if the M had those). Then the chassis will just slide out of the rear (remember to unplug the internal antenna first). Various bits might fall off on the dial side, like tape/foam strips that once had glue, and the small light reflectors at the sides. Watch out for those, and put some new tape to secure the internal antenna wires in place before assembling it again.

I agree, a nice and classic radio that is a must in every collection.

I know that some people like to spray contact cleaner etc. but I wouldn't
recommend it.
It always seems to go places where it doesn't belong and in the best cases
it won't harm anything. It's my experience that it rarely does any good
and some types even add to the mess by not evaporating completely.

My advice would go something like this;
Take off the knob and place the radio upright, standing on it's rear side with the connectors etc.
Let a tiny drop of acid-free oil (sewing-machine oil) run down the
shaft to the bushing that has seized.
Leave it to soak overnight and it will penetrate and dillute the
remains of the old and hardened lubricant.

Add one more drop for good measure, wipe the shaft clean using a tissue or similar and mount the knob again.

Martin

Mika and Martin,

Thanks for the warm welcome.

I will first try to remove the knob and see if cleaner and oil will work, before I attempt to remove the case. I had to put some oil on the small screw on the knob because it wouldn't turn. I let it sit overnight and will try to remove it todayt. I will post again on my success.

 Again, thanks for the help.

 Chas.