Posted by John Haine on 19/02/2019 16:07:21:
It would help if you could be a bit more specific as to what the problems are and why you think it is beyond help. It could for example simply be that it needs a new speed control potentiometer if it is "temperamental" – that implies that sometimes it works and sometimes it doesn't. Yes that controller might do the job, looks the right sort of rating. Note that it has provision to drive a field winding which you might or might not need on the machine motor.
Symptoms plus a couple of photos of the inside would help, it looks like a nice machine and well worth preserving.
Ok, the motor would sometimes start, sometimes not, then the what seemed like the on off switch popped and tripped the fuse box, apart the that all the connections on the circuit board are kinda loose and brittle, and just looks like things are going to start falling apart soon, which is why for the sake of £20 I'd replace it if possible.