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Message |
    
Blaz38
Tinkerer
Username: Blaz38
Post Number: 11
Registered: 01-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2011 - 06:50 am: | 
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Hello everybody classic enthusiasts.
I have a Retina I, bought at a charity. Compur shutter 1s-1/500s. Shutter speeds 1/10-1/500 look and sound OK (not yet measured); B is also OK. Speeds 1/5, 1/2, and 1/1s do not work: shutter stays open until the shutter ring is moved outside that range.
Have dis-assembled (and re-assembled, several times) the shutter and traced the problem to the slow speed governor (not sure about the usual name, but you get the idea). See attached pic. Rightmost wheel engages a train of gears to the left, up to a caorse-toothed gear that can rotate only by flipping a rocker arm (basis for slow speed timing). According to the position of the lever visible at left, the mechanism can be in one of three states as concerns the constrains on the rightmost wheel:
- "free", engages only the train of gears
- must flip rocker arm
- blocked
When the shutter speed selector is in the range 1-1/5s, the right wheel can be pushed by the master ring (that links all shutter sub-mechanisms) only with external (that is me and a fine screwdriver) help. I did note that the position of the slow speed assembly can be adjusted (closer or further from the master ring); tried, but always the timer with the rocker arm needs extra force to complete the cycle. Tried to lubricate (with premium jewelry oil) no success. Removed the lubrication by immersion in isopropyl alcohol, no success.
Of course, a camera with 1/10-1/500 makes a nice shooter; but, still, I'd like to restore full functionality. Any help will be greatly appreciated.
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Mattboston
Tinkerer
Username: Mattboston
Post Number: 22
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2011 - 11:11 am: |
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I had a very similar problem once that drove me mad. Everything seemed to be set up and working properly, but that initial lever just lacked enough force to move the train consistently.
Well, I don't remember what fixed it exactly- but I seem to remember I had a spring (outside of the gear train you show) that was in the wrong spot. One of the flat, leaf type springs was putting pressure on the wrong side of one of the levers that engaged the delay gears.
I think.
Good luck- and double check all the springs.
Matt |
Mattboston
Tinkerer
Username: Mattboston
Post Number: 23
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2011 - 11:14 am: |
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it was a spring like one of these three- or possibly another one underneath these.
Matt
http://i4.photobucket.com/albums/y118/mstott/rolleiflex%20automat%20K4A/IMG_2385-1.jpg |
Ron_g
Tinkerer
Username: Ron_g
Post Number: 70
Registered: 07-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2011 - 04:00 pm: |
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I disassemble the escapement and clean all of the parts individually when I clean those shutters.As long as I am in there I want to do as much as I can to insure a successful job.
When I take the shutter apart I measure the clearance between the escapement and the outer ring with a round automotive feeler guage so that I can assemble it as it was when I got it and hopefully noone else had been in there before me.
I think that that would give me the best chance of it being timed right when I put it back together again.Ron G |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 175
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2011 - 12:19 am: |
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Had the same problem on a Retina 1 (Type 149) only a couple of weeks ago! The slow speeds were sticky, but cleaning the retard mechanism had no effect.
I found that the retard lever (that's the shaped quadrant on the mechanism that has to be pushed out of the way) had worn a notch where the tab on the main lever (that's the 'cocking lever' that turns round the barrel) pushes past it. I ground out most of the notch and polished it. With a bit of grease on the lever, it now works very well, with good times at all speeds.
You can download a manual for the shutter at http://benoit.suaudeau.perso.neuf.fr/manuels_rep/obturateurs/compur_rapid_shutte r_repair%282%29.pdf . It explains very clearly how the shutter works, how to dismantle it, and how to adjust it. It will also explain how to reset the hairspring if the retard lever quadrant has become disengaged, which is 99.9% certain to have happened during cleaning. |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 176
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2011 - 12:25 am: |
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P.S. According to the manual, it is also possible to position the retard mechanism so far inwards towards the barrel that the retard lever blocks the main lever altogether. In this case the problem would clear if you move the retard-lever end of the mechanism a bit further out. |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 56
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2011 - 07:28 pm: |
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Thanks for the link to the manual Steve.
PF |
Blaz38
Tinkerer
Username: Blaz38
Post Number: 12
Registered: 01-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 15, 2011 - 01:30 am: |
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Thanks to all for the advice. Particularly to Steve_s for pointing out the Compur rapid manual; I had downloaded a longer document, but that addressed more recent shutters; the reference you give seems to be just the model I have. I'll also check if the "retard lever" has a notch where the main ring hits it to push it out of the way; that would pretty well explain the symptom; without an external advice I would have been reluctant to start grinding metal. Ron_g: Unfortunately I did not measure the position before dismounting the escapement (then I need to follow the adjustment procedure from scratch, using a photo-electric speed measurement); as for dis-assembling it, that is too risky for me. Mattboston: I'll check the springs. |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 177
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 15, 2011 - 03:23 pm: |
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If you do find a notch and grind it out, obviously you should be very careful to remove as little metal as possible. I'd do it by hand, if you can, rather than risk taking too much off using a Dremel or similar tool. I had some small sticks of some kind of abrasive material which did the job. Possible the metal might be soft enough to use a needle-file, but I didn't try it. |
Blaz38
Tinkerer
Username: Blaz38
Post Number: 13
Registered: 01-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 16, 2011 - 02:48 pm: |
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It looks like I have repaired the shutter, with the help of the Repair Forum. At least now all slow speeds are operating consistently, if not (yet) accurately. Special thanks to Steve, who provided two key ingredients:
1) Indeed there was a burr on the retard lever, though from its shape I suspect it was there during the last 70 years; looks like a burr on a stamped sheet metal part. Removed it with a small file.
2) The Compur Rapid Manual (very detailed, really Compur for Dummies) provided another key information: that _both_ ends of the retard assembly can be radially adjusted; the adjustment on the retard lever side, hidden under the larger screw head, will be essential for adjustment of retarded speeds, 1/10 being most critical as the man ring hardly engages the retard lever.
Again thanks to all who responded. |
