Zorki 4 after CLA: everything working except for B

[fub]

Hello everybody,
this is my first post on this forum 🙂

i have recently acquiered a Zorki 4 (1964 Model) that had problems with a slow second curtain at slow speeds. So i did the deed and gave it a CLA. It was the first time i have been doing such in depth CLA on any camera.
I think it went pretty well. Right now i have the slow speed machanism installed and all the slow speeds work fine. The only problem i still have is that B is not engaging at all. I have taken that delay mechanism out so many times last night that my fingertips are still hurting and the skin is still peeling off. i adjusted the little notch in relation to the little gear that drives the lever that blocks the 2nd curtain in all possible combinations, i tried different notch positions with the machnism installed and tensioned (losening the little ring on top, moving the big gear around) and i have read all the manuals and seen all the videos at least twice.
everything seems to be how it should be it is just that that little lever that should stop the 2nd curtain from closing is being held open by the little gear under the delay mechanism when in B mode.

i am actually very close to giving up on this nonsense. you guys are my last resort.

with the picture i try to show you the situation of the lever for the 2nd curtain when in b mode. one with shutter wound and one with shutter released.

does anybody have any ideas why this annoying situation is the way it is?

did i mention that it is really frustrating and annoying? 🙂

cheers

 

[fub]

shutter released

 

[Valkir1987]

did i mention that it is really frustrating and annoying?


everything seems to be how it should be it is just that that little lever that should stop the 2nd curtain from closing is being held open by the little gear under the delay mechanism when in B mode.

This is the moment in the progress when you need to take a break. If you made it this far, patience will do the trick. This is your first serious CLA. After years of repairing, curiousity replaced my frustration. (mostly)

The notch that holds the second curtain for the slow speeds, should open and close when you manually wind the gear for the slow speeds. In rest, the notch should stay open. The spring on the slow speed mechanism needs enough tension.

When set to 1/125, the speed selector knob should almost touch the brass knob of the big gear wheel of the speed selector.

 

[JeffS7444]

I encountered something similar with a Nikon F, and again with a Samoca, and I think it took me a few days to solve: I needed to bend a soft metal part slightly. Perhaps I had straightened it out previously, thinking it was misshapen. I realized that in 1950s Japanese cameras, and Compur leaf shutters, that's how some critical adjustments were made, so be careful about what you attempt to "correct"!

 

[fub]

I needed to bend a soft metal part slightly.

found the reason! that little spring that goes on the bracket for the second curtain (the one with the long spindle going to the bottom of the camera) seems to not have enough tension. when i hold down the bracket with my finger the 2nd curtain stays open and releases when releasing the bracket. i did that a bit and eventually B startet working, but now it is not working again 😀
any tips on how to improve the downward force of that little spring that pushes the bracket down? should i increase or decrease the bend angle of that spring?

exciting! almost there 🙂
attached a picture of bracket, spring and how far they are being pushed down

 

[JeffS7444]

found the reason! that little spring that goes on the bracket for the second curtain (the one with the long spindle going to the bottom of the camera) seems to not have enough tension. when i hold down the bracket with my finger the 2nd curtain stays open and releases when releasing the bracket. i did that a bit and eventually B startet working, but now it is not working again 😀
any tips on how to improve the downward force of that little spring that pushes the bracket down? should i increase or decrease the bend angle of that spring?

exciting! almost there 🙂
attached a picture of bracket, spring and how far they are being pushed down

I try to avoid bending springs, because when all else is working correctly, even aged springs usually provide all the force that's needed. See if there's something else that you've overlooked.

 

[fub]

I try to avoid bending springs, because when all else is working correctly, even aged springs usually provide all the force that's needed. See if there's something else that you've overlooked.

after i opened the first curtain via pressing down on the breaket directly i can reach over to the normal shutter release button and hold that button down instead of the breaket. when i slightly move the button the breaket moves with it. when the shutter is not wound, the breaket does not move when i press the shutter release button, even though the spring plate at the bottom does.
could it be something about the spring plate at the bottom? maybe wrong tension?

edit: got it done! i relubrricated the shaft but that really did not help much. ultimatly i bend the torsion spring a bit to increase downforce. it works! i probably have bend the spring a bit too much during reinstallation of the shutter. had to take out the part many times. anyways it works now! i'll stop for today and reassemble the rest tomorrow