Spring in a PRONTOR S

Discussion in 'Camera Building, Repairs & Modification' started by SalveSlog, Jan 27, 2018.

  1. SalveSlog

    SalveSlog Subscriber

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    The spring (A) in this PRONTOR S don't put enough pressure on lever (B) to engage properly at the pin (C). That spring may simply have lost its tension. But I wonder if there is something at the springs left end that I don't understand. Does that springs position look normal?

    spring-tension.jpg
     
    Last edited: Jan 27, 2018
  2. shutterfinger

    shutterfinger Subscriber

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    My Prontor S is a different layout. What is the speed ring on yours? Mine starts at 1 on the left with B on the right.
    DSC_2877_00001.jpg
     
  3. OP
    OP
    SalveSlog

    SalveSlog Subscriber

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    Mine is opposite with B on the left on the front plate of the lens. It's on a Welta Reflekta II.

    But I found the spring in the parts list (PRONTOR-S-SV-SVS1.pdf : it's number 00310-104). I could see that mine was bent close to the right "A" in my picture and I picked it out and bent it back to approximate original shape. So now it does its job OK.

    But I'm deeper in trouble now, because to pick out that spring I figured that I had to remove the lever to the left of the left "A". That would have worked just fine if the screw holding that lever had not also held one end of the main drive spring!

    Luckily, this is not someone else's camera; it's mine. Ugh!
     
  4. OP
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    SalveSlog

    SalveSlog Subscriber

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    Yeah, I'm now proud and happy! (For a while?) I got the main spring back in place. Taking my time to make a plan paid off.

    The main spring did not unwind totally because the shutter mechanism was inside the casing, so the spring only unwinded 2/3 turn and stopped against the casing wall. By making 3 simple tools from brass wire I was able to:
    Hold the driving latch spring (00310-104) in the right position with my small U-shaped "tool".
    Pushing the end of the main spring under the cocking lever arm with the most distant tool,
    and catching it to drag it home with the tool in the middle.
    Then I was able to put the screw that holds both springs and the lever that I had removed back in place!

    But I have to admit: it is rather labourious to be an amateur!

    If anybody ends up in the same situation as me and would want me to explain the above better, please let me know.

    tools.jpg
     
  5. John Koehrer

    John Koehrer Subscriber

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    Back in the day before plastic cameras it was common for repairmen to make special tools for specific cameras. Making parts
    with hand files too.

    YA DONE REAL GOOD!
     
  6. OP
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    SalveSlog

    SalveSlog Subscriber

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    Thank you, John.
    Job is now finished, including a new mirror. And the shutter is spot on on 1/1 and 1/25. 1/300 is at ca. 1/180 for small aperture and 1/450 with full aperture when I only let light through the periphery of the lens. The other shuttertimes are a bit slow, but within acceptable margin and they are stable.

    I like this camera, probaly mostly because it's manageable for an amateur like me to service it. (I'm not a good photographer, anyway. Haha!) The film advance has a primitive double exposure lock which makes a loud clack or two (!) for each frame, and it depends on the red window.

    Time for testing!

    welta_reflekta_ii.jpg
     
    Last edited: Feb 4, 2018
  7. shutterfinger

    shutterfinger Subscriber

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