Originally Posted by keithlester 
I've been watching this thread, as I am in the same position as the OP. I have checked and found with my TC that there is an open circuit on the pin concerned. The lens itself provides a short to the mount when switched to A mode. Further checks show that both ends of that connection have an open circuit between them. Is this going to be a nasty fiddly job, or can I expect to open the converter and find a simple solution? As best as I can tell, all the connections are open circuit. I assume there should be a through connection on each contact. Is it likely to be a flexible ribbon cable, plugged in at each end or are the connections soldered? I don't fancy removing the mounts, for fear that a load of small components are going to fall out.
Any advice you can give would be much appreciated.
Regards, Keith
Update on my situation. I bit the bullet, and removed the rear mount, the contacts should all be connected by extensible spring connectors. All but one have fallen off the rear mounting strip. I think I will need to fashion a tool to enable me to lift them back into place. Wish me luck, I'll need it.