i'm also going down the line of a short circuit but when i use a lens without the contacts i don't get the slap, its only when i use the t2 mount, so my first move is to try a new mount and the see what happens

the mirror starts to slap closed at the press of any button, dial or switch without letting me take a picture, and the only way that i can stop this is my putting on a 'standard' pentax lens

i have a Pentax K-r i have various lenes both auto focus and manual, the problem that i am having is the dreaded 'mirror slap' but only when i am using a 500mm with a t2 mount.Why? any ideas.
Cheers for any help Garry