Grundig 3028 Cabinet Restore

[Geaney]

I've started to see about getting the AM section working. I found a dry joint one one of the internal antenna down leads. Fixed that and powered it up and we have AM reception! Joy is short lived however - about halfway down the dial all is lost once again. I have a dead short across the tuning condenser. I've tried cleaning it out with WD40, compressed air, etc. and so far no luck. I can't see where the short is happening so I'd love to know if any of the expert team has come up with ways of resolving this - or at least finding out exactly where the short is.
Help!
Cheers, John