HI Ian.
You could try cleaning that area with some switch cleaner, and dry it out. but I think if it did work it would only be for a while.
Personally I would drop one or both of these guys a PM they should be able to help you out.
Marinabrian
https://the75andztclub.co.uk/forum/p...=newpm&u=13883
big Russ
https://the75andztclub.co.uk/forum/p...=newpm&u=13883
Also post this in the tech section you will get better coverage