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Focal7175
Tinkerer
Username: Focal7175
Post Number: 13
Registered: 08-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 12, 2008 - 09:16 pm: | 
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I have two Fujica ST-801 cameras and one is displaying a problem with the film transport.
Here are the symptoms:
When no film is loaded in the camera, the ST-801 that works correctly will produce a slight "click" indicating something is getting engaged (or disengaged) at the conclusion of the film crank's travel when cocking the shutter.
The ST-801 with the problem does not produce this click at the conclusion of the film crank's travel when cocking the shutter.
When film is loaded in the camera, and I attempt to advance the film after releasing the shutter, the film crank does not snap back to its position after it reaches the end of its travel (again, because something is clearly not being engaged or disengaged). I can, however, for the first few frames of film manually guide the
film crank back to its regular position. With successive frames, the effort required to advance the film and guide the crank back to its regular position increases. After a handful of frames the shutter will no longer release unless the rewind button on the bottom of the camera is depressed.
If I open the back of the camera with the problem when no film is loaded, release the shutter, and crank the film advance I notice some strange behavior. The very, very first bit of travel of the crank results in the take-up spool moving very slightly in the same direction as the film crank. The next bit of travel (and we are talking about a VERY small amount) results in the take-up spool ceasing this motion. The remainder of the film crank travel when cocking the shutter results in the take-up spool moving in the opposite direction of the film crank, while the guiding rod moves in the same direction of travel as the film crank. As mentioned before, the very conclusion of the film crank's travel does not produce the click that the healthy camera demonstrates. Once the film crank is released at the conclusion of its travel, more strange behavior results. The first 20 degrees of the film crank return results in the take-up spool moving in the same direction of travel as the returning film crank. The next 50 or 60 degrees of the film cranks return motion also demonstrates movement of the take-up spool in the same direction as the returning film crank, but now the guiding rod is moving in the opposite direction as the returning film crank.
By comparison, neither the guiding rod nor the take-up spool demonstrate any movement when the film crank is released at the end of its travel to cock the shutter.
Does anybody have any suggestions as to what is wrong and how much of a project it might be repair?
The camera works marvelously otherwise.
Any help is appreciated - my thanks in advance. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 486
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 13, 2008 - 08:45 am: |
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That sounds odd all around. I can't make much out of the behavior of the takeup spool. However, your description of the "when film is loaded" condition sounds like the shaft of the rewind knob is jammed, possibly bent, and refuses to rotate as the film is advanced.... thus, you can advance it while there is slack on the spool, but once the slack is taken up you can't go any farther. |
Focal7175
Tinkerer
Username: Focal7175
Post Number: 14
Registered: 08-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 13, 2008 - 10:42 am: |
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Rick,
The rewind knob is fine. Something is supposed to engage or disengage at the conclusion of the film crank's travel when cocking the shutter/advancing the film, but is not.
Perhaps something is stripped |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 487
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 13, 2008 - 11:37 am: |
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I'm not sure then why it behaves differently with and without film... the only other place where the film touches anything is the sprocket shaft, so maybe that's it. The wind spool is supposed to have a slip clutch so that it lets the sprocket, rather than the takeup spool, determine how much the film will be advanced. If that clutch is jammed, then the spool will try to keep pulling film after the sprocket locks, and they will fight each other. |
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