slow Sekor C 65mm

Discussion in 'Medium Format' started by mag_miksch, Jul 3, 2010.

  1. I havent used my 65 mm lens for 2 years and now it runs very slow times, maybe 2 stops or so, the images are terrible overexposed. Is there a way to do a CLA by myself, or is there a instruction how to dissemble the shutter?
  2. Have you ever done a CLA on a shutter before? Do you have the right tools and skills? They're not terribly hard, no worse than any other shutter, but there's about 1,000 ways to screw up, and the shutter cocking/firing mechanism is tricky to reassemble properly. I'd wait for Paul Ron to chime in and send it to him if I wasn't 100% comfortable (and since you're asking, likely your not...)
  3. I have done similar work with older LF lenses, but they are much simplier, I screw out the cells and have the shutter that I can open removing some screws.
    My problem is, I am european resident and dont know a place for CLA at a reasonable price; what I have seen here in the forum, works like this are much easier and cheaper done in the USA, but shipping and handling and custom fees and all together makes it impossible to go this way.
  4. My problem is, I am european resident and dont know a place for CLA at a reasonable price​
    Where in Europe? There are plenty of UK based repairers.
  5. paul ron

    paul ron NYC

    Mamiya lenses are similar to LF with some minor exceptions of the shutter mount in the barrel. Otherwise take off the name ring, remove the front cell, remove the rear cell. Now once the cells are out the dissasembly is all done form the top down like a layer cake.
    Before you start, work on a clean surface, preferably a piece of excersize matt. Use a weekly pill organiser as your storage container for the screws so you keep the process in order as you go layer by layer. The screws are slightly differnet n have to go back to where you took em out of.
    Take the front cone out n now you will see several screws that holds in the first ring. Then the next n next. Now turn the lebns over n remove the retaining ring in the back just around the rear cell mount. Oh your lens may have 4 screws holding the barrel halves on the sides of the lens, loosen them then take the retaining ring out and that will split the halves n drop the shutter mount.
    The shutter mount has a few screws holding the shutter inplace. first remove the very thin metal of the preview lever, one tiny screw. Now the shutter mounting screws, one is the mirror up center screw, the other is at each end of the preview lever n center, another is the M/X spring. The shutter will drop out of the mount now.
    Don't take the back of the shutter off to expose the bearings, they don't need any service unless the lens cocking mechanism is full of sand.
    You say you know your way around a shutter so do the complete wash n relube. The shutter if it is brass needs very little lube if any at all. The only places that needs very light watch oil is the pins of each gear, just a micro dot on each is more than enough. The center ring doesn't need any lube, just be sure the center where it rides it is very clean. The rub spots of the booster spring n like parts get a very thin film of grease, Lubraplate lithium.
    Reverse the process n reassemble the lens. Oh put the mirror up switch in the mirror up position, it makes assembly easier.
    If you are as handy as you say, this is a walk in the park.
  6. @Steve:
    Could you be so kind to link me to some of them, please.

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