Yeah, this is a weird one and, before anyone calls on, I checked. This is not a capacitor.

Fresh batteries. Powers up. LED indicators light in Manual and Auto and the M light. Meter is operable and seems accurate. Battery Check is fine. Shutter button circuit closes perfectly.

Shutter will not release because the shutter will not remain cocked when the lever is wound. The lever winds about 180 degrees to cock the shutter. After about 50 degrees of return travel, the shutter trips and the curtains return to their normal post-exposure position to the left. Have tried this in all modes (A, Man (all speeds) and self timer), all with the same results. No noticeable gap between the curtains. The move freely in their channels and are not jammed.

I have a few leads on this one.
IC3-pos 1
HIC- pos 4,5,6
Switch 4
Switch 12
Flexible Board position 1,3,13
4 different wires.

Just checking for bad solders and such. But before I go a tearing (I already made a practice run from the top and from the bottom to get familiar and reassembled with success), has anyone run across this peculiar problem and found a simpler solution to attempt?