Zorki 3 vertical rangefinder adjust

[MXP]

Can somebody explain a bit more in details than one of the "headline threads" on how to adjust the vertical alignment on a Zorki 3. The moving image in the VF is a bit to high so I want adjust it a bit down. I have removed the top cover as shown at the two pictures. How to proceed?

 

[Dez]

Rangefinder adjust

Rangefinder adjust

It lookes like the round window had been glued in place. Does this look like it can be rotated, same as the vertical position adjustment for the Leica screwmount cameras?

Cheers,
Dez

 

[MXP]

It lookes like the round window had been glued in place. Does this look like it can be rotated, same as the vertical position adjustment for the Leica screwmount cameras?

Cheers,
Dez

Yes, I think so.....and now I understand better the previous explanation in one of the threads in this forum. The round window is a prism and not just a piece of glass? .....it is locked with some shellack and I probably need some alcohol to "unglue" it.

Thank you!

Max

 

[Sonnar Brian]

I hacked a fix, and it is still working. I've done this on one of my Zorki 3M's, and a Kodak Signet 80. Neither had an adjustment for the Vertical alignment.

I put some foam rubber on top of the mechanism above the RF window so that when the top plate was on the camera, it exerts a slight force to press it down. After all these years, the mechanism seemed to require a little push into place. It worked.

 

[ZorkiKat]

Clean the crusty brown stuff around the RF wedge collar. It will go off easily with acetone. A Q-tip liberally moistened with this solvent will do the job, and have lots of spare qtips ready. Let some of the acetone seep in since the shellac may have seeped in too.

Once the old glue is off, you should now be able to turn the wedge freely. The wedge was cemented because it was prone to move and readjustment always required the lengthy top removal to access it.

If you've ascertained the position of the wedge (do this several times- with and without the top cover off, with the eyepiece in place to make sure), fix the position with nailpolish. Red is better than black, in case you need to do some future repair, it will be easy to see which to remove. Nailpolish is easier to work with than shellac. And nothing to prepare too, for the tiny amount you'd need to cement it. A tiny dab in 2 or 3 points in the wedge's collar should fix it to its mount.

 

[MXP]

Clean the crusty brown stuff around the RF wedge collar. It will go off easily with acetone. A Q-tip liberally moistened with this solvent will do the job, and have lots of spare qtips ready. Let some of the acetone seep in since the shellac may have seeped in too.

Once the old glue is off, you should now be able to turn the wedge freely. The wedge was cemented because it was prone to move and readjustment always required the lengthy top removal to access it.

If you've ascertained the position of the wedge (do this several times- with and without the top cover off, with the eyepiece in place to make sure), fix the position with nailpolish. Red is better than black, in case you need to do some future repair, it will be easy to see which to remove. Nailpolish is easier to work with than shellac. And nothing to prepare too, for the tiny amount you'd need to cement it. A tiny dab in 2 or 3 points in the wedge's collar should fix it to its mount.

Thank you very much for the explanation. I have also previous used glue used for gluing wood to fix positions of glass in cameras. I may try this also here.....

 

[martin_t]

Acetone does work best. Be careful too if you use tweezers
to turn the collar. If the collar doesn't turn easily, you'll be
surprised how fast the tweezers will skip off and skate across
the glass.

Some of the Zorki 3 RFs are trick. I have one that had never
been worked on and yet there was no way to get the
horizontal adjustment zeroed in. Thinking it was a misglued
prism, I popped it off with heat from a hair dryer then reglued
it. What I didn't realize is that there is a coupling plate secured
by a screw down at the other end of the RF arm close to the
smaller block prism. This should be used instead to deal with
any horizontal alignment problems that can't be corrected
by the usual adjustment screw (through the front cover).

 

[wolves3012]

It lookes like the round window had been glued in place. Does this look like it can be rotated, same as the vertical position adjustment for the Leica screwmount cameras?

Cheers,
Dez

If it's well and truly stuck and you can't rotate the prism, it's possible to adjust the mirror behind instead. See the "HOW TO CLA - Zorki 4K" sticky for pictures, the Zorki 3 uses the same VF/RF mechanisim. Beware that the adjustment is much coarser than using the prism and will require only the tiniest of alterations to the screws!

 

[MXP]

I tried to remove the shellac and dilute it but was not able to rotate the prism and I didn't want to use to much force. So I assembled the camera again. The vertical error is not that big so I think I can live with it until I one day may send it to a more experienced repair person.

 

[martin_t]

That's no surprise. The collar is pried out via its two flat sides
in small increments, then turned, esp. when the shellac is that
stubborn.
If you decide to have another go, first thing I'd do is get all that
old shellac off of there (Ace HW acetone), then mark the
original position as ZK says. Dab it again, then pry it out,
one side then the other. Clean the collar up, reseat it, check
alignment, and when it's right put a small dab of adhesive
on each side. It'll stay put. You won't have to turn the collar
much more than 1 mm from the sounds of it. Good luck.

 

[MXP]

OK!
So it is possible to take the round prism (collar) out by force....by using a small screwdriver maybe? .....then clean and then reinsert again and adjust it.....and then fix the position?

 

[Sonnar Brian]

With the top off, look at an object and try pressing down over the RF window. If that aligns it up, you can try my stupid-idea fix.

If you pry it out with a screwdriver, it could break. This is old glass.

 

[wolves3012]

OK!
So it is possible to take the round prism (collar) out by force....by using a small screwdriver maybe? .....then clean and then reinsert again and adjust it.....and then fix the position?

As Brian points out, it's glass. Whilst you may be able to pry it out, gently, by prying both flats, there's a real risk you'll crack the glass.

Although others have suggested acetone, I prefer alcohol since it's a less aggressive and slower-evaporating solvent. My method is to lay a tiny piece of paper towel over the glass and drip alcohol onto it. Keep adding more as it dries out. After a while it'll soften the shellac enough and you can rotate the prism or remove it. So far I haven't had that method fail. Cotton buds would probably work equally well but the point is to keep the area soaking for a while (not to the point that it runs everywhere, just damp!).

 

[martin_t]

OK!
So it is possible to take the round prism (collar) out by force....by using a small screwdriver maybe? .....then clean and then reinsert again and adjust it.....and then fix the position?

Yes, but not by force. A very careful, incremental lifting up of the
collar via the flat edges with a narrow precision screwdriver. You're
really nowhere near the glass and the collar is reasonably strong.
Any small prying force applied to it will not transfer to the glass,
breaking it. Perfect nonsense.

Again, acetone is the way to go, imho. You should also avoid
tampering with the small bock prism assembly another poster
mentions. Zorki 3 RFs are not exactly the same as the later
Zorkis. Besides, it's rarely necessary.

 

[wolves3012]

Yes, but not by force. A very careful, incremental lifting up of the
collar via the flat edges with a narrow precision screwdriver. You're
really nowhere near the glass and the collar is reasonably strong.
Any small prying force applied to it will not transfer to the glass,
breaking it. Perfect nonsense.

I wouldn't like to put the theory to the test. Even a small screwdriver's prying force is multiplied by the leverage of the handle against a small distance at the base. Why risk it?

Again, acetone is the way to go, imho.

I beg to differ, look up the properties of shellac. I quote:
Soluble in methanol, ethanol, propanol, iso-propanol, butanol, butylglycol, benzlalcohol, insoluble in acetone, methylethyketone, ethylenglycol, chlorinated hydro carbons, alphatic and aromatic solvents, esters.
I don't see the fascination with using acetone. Shellac isn't soluble in it unless some water is added. It's harder to obtain, it has a much lower flashpoint (i.e. it's easier to ignite) and it evaporates about 3 times faster than alcohol.

You should also avoid tampering with the small bock prism assembly another poster mentions. Zorki 3 RFs are not exactly the same as the later Zorkis. Besides, it's rarely necessary.

I may be wrong but I thought they used essentially the same RF mechanics. I'll have a peek and see.
EDIT: you're right, they are not the same. I think it is still possible to adjust the mirror but I'd agree this is not the best or simplest way.