" One of them is Ben Jacoby in Brooklyn with "High End Audio Repair". Anyone here have experience with Ben? Although if Steve will recommend him then I believe he is more than capable of repairing my unit :-)"
I don't know him, but I have heard good things about him.
It just occurred to me that Wadia was bought out not long ago by the group that owns ARC and McIntosh. Even though this is the third time for them, I think its a good thing. The company is now well funded and they brought back some of the original Wadia people. Your 850 was made during that era, so someone there has direct experience with it. Quite often, when a business like this changes owners, the buyer ends up with some NOS parts. I would call them. You have nothing to lose.
This is a long shot, but I would also ask Wadia if you can use a transport from one of the other players. The upgrade for my 861 to SE status was just the transport. Maybe they kept the old ones. Find out if they're compatible with the 850, and if they are maybe they'll give you one.