Hi y’all,
I just picked up an S2A that’s in very nice shape, minus the ubiquitous focus screen and mirror foam issues, but it has an annoying quirk. About 1 out of 10 shutter releases, the shutter won’t actually fire until the camera is thunked on the bottom or, occasionally, if the aperture stop-down button is pushed. The mirror always flips down and the screen blind rolls out, but the shutter itself doesn’t run and thus the mirror and blind don’t return to home position.
If the stopdown button is held while the shutter is tripped, it fails to fire much less frequently, I’d say 1 in 20 shutter trips. It will occasionally fire sluggishly with lens mounted and stopdown not held, IE, there will be a ~1/4 second delay during which it sounds like mechanisms are moving sluggishly, and then will lurch forward and the shutter fires. There have been no problems with mirror return or aperture re-opening when the shutter does fire
The shutter consistently fires when no lens is mounted. There is no discernible difference in failure rate with or without a loaded magazine mounted
So far, I’ve lubricated the stopdown linkage in the focus helicoid, both the lever that rides on a ring inside the bore and the sliding arc on the rear face of the helicoid. This seems to have improved the failure rate from the previous ~3/5 to the current ~1/10.
Has anyone else had this problem? It seems apparent to me that the nature of the problem is that the aperture mechanism can’t impart enough force to close the aperture against its return spring. I wondered if there’s an adjustment somewhere for the stroke of that mechanism. As I understand it, the action of the mirror falling seems to trigger the stopdown mechanism, so I had the thought that perhaps it’s not moving though its full travel, explaining the marginal performance rather than outright failure.
I understand that there are fewer and fewer folks willing to work on the mechanical Bronicas, but I’m pretty decent working with small mechanisms and clockwork—I got an Kiev-60’s double-exposure lockout functioning, for example—so I would like to at least try to fix this camera, especially since it appears to be in near-mint condition otherwise (excepting the foam, which I plan to fix today). I eagerly await any insight folks can offer, as I’m pretty excited about my first medium format system camera, particularly about the interchangeable backs.
I just picked up an S2A that’s in very nice shape, minus the ubiquitous focus screen and mirror foam issues, but it has an annoying quirk. About 1 out of 10 shutter releases, the shutter won’t actually fire until the camera is thunked on the bottom or, occasionally, if the aperture stop-down button is pushed. The mirror always flips down and the screen blind rolls out, but the shutter itself doesn’t run and thus the mirror and blind don’t return to home position.
If the stopdown button is held while the shutter is tripped, it fails to fire much less frequently, I’d say 1 in 20 shutter trips. It will occasionally fire sluggishly with lens mounted and stopdown not held, IE, there will be a ~1/4 second delay during which it sounds like mechanisms are moving sluggishly, and then will lurch forward and the shutter fires. There have been no problems with mirror return or aperture re-opening when the shutter does fire
The shutter consistently fires when no lens is mounted. There is no discernible difference in failure rate with or without a loaded magazine mounted
So far, I’ve lubricated the stopdown linkage in the focus helicoid, both the lever that rides on a ring inside the bore and the sliding arc on the rear face of the helicoid. This seems to have improved the failure rate from the previous ~3/5 to the current ~1/10.
Has anyone else had this problem? It seems apparent to me that the nature of the problem is that the aperture mechanism can’t impart enough force to close the aperture against its return spring. I wondered if there’s an adjustment somewhere for the stroke of that mechanism. As I understand it, the action of the mirror falling seems to trigger the stopdown mechanism, so I had the thought that perhaps it’s not moving though its full travel, explaining the marginal performance rather than outright failure.
I understand that there are fewer and fewer folks willing to work on the mechanical Bronicas, but I’m pretty decent working with small mechanisms and clockwork—I got an Kiev-60’s double-exposure lockout functioning, for example—so I would like to at least try to fix this camera, especially since it appears to be in near-mint condition otherwise (excepting the foam, which I plan to fix today). I eagerly await any insight folks can offer, as I’m pretty excited about my first medium format system camera, particularly about the interchangeable backs.
