I just got an RB67 today from a camera shop used, with a Polaroid back, 120 back, and 90 3.8. When I got home, I loaded up some FP-100C in the Polaroid back and made an exposure. Came out really bright. Way too bright to be a metering problem; it was almost totally white. I took the camera inside and made another exposure of the coffee maker, camera sitting on the table. Again, really bright, except for the half-inch border on one side that isn't exposed at all. I took the back off to inspect what was going on. Apparently the lens was stopping down, but the leaf shutter wasn't engaging at all. The lens stopped down and the shutter never opened or closed; so until I cocked the lever again the film was being exposed. I fired some test shots without the back on and the shutter never opened or closed, unless i was shooting above 1/60. Apparently one of those test shots blew it all, since now the mirror is stuck up and if I press down the cocking lever it gets locked down and won't pop back up unless I forcefully press it all the way down. The lens is locked on; I can't remove it. The mirror will not pop down. I've wasted a roll of Portra 160 and 2 shots of a FP-100C pack. What can I do, besides take the camera back Monday? Anything I can try?