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Message |
    
Jimm
Tinkerer
Username: Jimm
Post Number: 1
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 04, 2008 - 08:05 am: | 
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I have recently acquired an RB67 Pro S in well used but serviceable condition. It came with a “C” 127mm lens. Both 127mm lens and camera work normally. But I was also given an older non “C” 90mm lens, when this lens is cocked and mounted to the body the shutter fires normally, but when the camera is re-cocked the cocking lever locks up at about mid travel and cannot be moved, and the lens now cannot be unlocked in the normal fashion. I can remove the lens with a “paperclip” through the hole in the camera front. The operation of the lens shutter appears normal, the shutter cocks and fires normally with no sign of damage; if the lens is remounted to the body the same sequence occurs. Can you suggest what the problem might be? I have a full service manual for the camera, but it does not include any detail on the lens itself. |
Krp
Tinkerer
Username: Krp
Post Number: 57
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 04, 2008 - 11:47 am: |
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The 90mm may have a broken main spring or some other debris blocking the cocking sequence. They are not hard to get into, or out of. I can help you further if needed |
Jimm
Tinkerer
Username: Jimm
Post Number: 2
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 04, 2008 - 01:19 pm: |
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Krp
If the main spring was broken as you suggest, would it still cock? I have taken the lens elements from RB lens out before for cleaning, but have never needed to go further, do you happen to have a parts breakdown showing how to access the shutter portion? |
Krp
Tinkerer
Username: Krp
Post Number: 60
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 04, 2008 - 01:58 pm: |
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I do not. Yes, the shutter will cycle w/o the main spring. The front and rear optics are 1/2 the battle sometimes. 4 screws to remove the depth of field scale, 3 short flat heads to remove the aperture ring and detent ring.
3 screws around the barrel and 2 for the pc socket if present.(not on early lenses) Then the retaining ring on the back side of the shutter. Set to Mirror up on the pivot button. Watch for loose spacer rings once the shutter is out.
The rest is fairly simple. The aperture stop down arm has a spring that will be loose and the center screw on the plate for the arm. The plastic arm for flash setting M/X is also a loose piece. That should get you to the final 3 screws to remove the cover plate on the front of the shutter.
I can provide you with a good photo of the shutter in working order |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 96
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 04, 2008 - 08:50 pm: |
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Sounds like the lens is not staying cocked once it is mounted. Perhaps the camera is not taking the actuating ring around far enough for it to lock at the green dots.
Does the lens cock and fire manually? What happens if you don't take the pins to the red dots, does it fire by itself snapping back or stays put where it is?
It can be the camera at fault just as well.
If you had a broken main spring the pins would move freely and not spring back when fired manualy. |
Jimm
Tinkerer
Username: Jimm
Post Number: 3
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 07, 2008 - 09:41 am: |
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Many thanks for your reponses. Had a chence to look at the lens last night and dis-assembled it. Only problem I found was that the flat leaf spring for the mirror lock up button was out of position. It had somehow rotated through 90 degrees. When I re-assembled the lens, it worked normally. I can only assume that the spring somehow caused interference to the shutter mechanism. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 97
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 07, 2008 - 03:59 pm: |
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That can do it. |
