Zorki 4 stiff 1st curtain

[Maurits88]

Dear members,

I am doing a CLA on a Zorki 4. The first curtain goes not very smooth, even after the CLA.

It also makes a sound as if you strip a roll adhesive tape. I increased the spring tension, but resistance is still there and it does not sound nice. Also, the curtain does not move 100% vertical but slightly diagonal.

What can this be? Is there an easy way to fix it?

How many turns can I give the tension spring at maximum?
No problems with 2nd curtain by the way.


Will try to make a video of it and upload it later.

I have a donor Zorki 4 so if needed i can exchange parts.

Thanks for help!

 

[Sarcophilus Harrisii]

Dear members,

I am doing a CLA on a Zorki 4. The first curtain goes not very smooth, even after the CLA.

It also makes a sound as if you strip a roll adhesive tape. I increased the spring tension, but resistance is still there and it does not sound nice. Also, the curtain does not move 100% vertical but slightly diagonal.

What can this be? Is there an easy way to fix it?

How many turns can I give the tension spring at maximum?
No problems with 2nd curtain by the way.

Will try to make a video of it and upload it later.

I have a donor Zorki 4 so if needed i can exchange parts.

Thanks for help!

Sounds like the material is no longer serviceable. I’d recommend changing both the curtains. Don’t bother trying to compensate with spring tension—it’s pointless. If the curtains aren’t running smoothly the acceleration curves will never be right, and you won’t ever be able to get all its speeds correctly set.

 

[wolves3012]

If the curtain moves on a slight diagonal, then one of the shutter tapes is, probably, broken or detached or wasn't attached properly in the first place. That's not an easy fix, it would require a total stripdown and re-fixing in the correct place - something that's hard to achieve with no reference marks. Not impossible but not something I'd want to attempt.

The noise *might* be lack of lubrication to the curtain roller pivots, most likely at the tension roller (the smaller one) rather than the drum end. If those are dry they make a kind of "zzzp" noise or a squeak. The post above is correct, adding tension is not the right solution and will probably make things worse. Approximately 2-4 turns of tension should be enough, with the shutter in the uncocked position (for the first curtain - the second curtain requires about a turn less).

 

[Ko.Fe.]

If curtain moves like this then CLA means you are getting into the rollers to clean spring with nafta fuel and apply new oil. Then you re-assemble shutter back.
If rollers are not in the holes, then curtains are not vertical.

Use anther camera to learn how to do real CLA. Retentioning goes from 4 to 7 turns maximum.
You have to watch opening between curtains to be even from top to bottom.
Curtains have to move "energetic".