Unreliable 'B' speed

[fanshaw]

I expect that some of you may have come across a fault that commonly occurs with Fed/Zorki shutters. The second curtain is not detained on the 'B' setting, intermittently, and you get something like 1/30 instead occasionally or often depending on the severity of the fault. I suppose it is due to wear of some component. I played with a Fed-2 and found that the shutter worked perfectly with the top removed and without the shutter speed dial. When the dial was replaced the 'B' speed didn't work reliably again. I assume the extra weight of the dial was responsible. Does this suggest changing shutter tension might cure the fault?

[Peter_Jones]

From my understanding of how it works (on my Zorki 5) , the first gurtain's "peg" knocks the release arm just enough to trigger the second curtain.

The crescent-shaped release arm is currently being "fine-tuned" on mine.

I wouldn't mess with the curtain tension until everything else is working smoothly, and only as part of a full CLA.

Hope this helps,
Peter

[Valkir1987]

The spring of the latchwhich catches the second curtain needs tensioning. Not the curtains. It works both downside and sidewards. A new one can be made and bent from steel wire, (like steel guitar wire)

[wolves3012]

I'll second Valkir's suggestion, it's unlikely to be tension unless it's ridiculously over-tensioned. If the spring he mentions is present and in good condition, check if it's applying a reasonable *inwards* pressure. Also, check the edge where the latch and release arm meet - they may have worn a bit off "square", allowing the arm to ride past and not get trapped. A bit of light filing to "square" it off again may help, if it needs it.

[Peter_Jones]

Go easy with the file

I'm only resorting to filing mine because I think someone's put the wrong arm in, or it never worked from new (!) - getting better with each fettling session though. Good luck !

[wolves3012]

Originally Posted by fanshaw

I played with a Fed-2 and found that the shutter worked perfectly with the top removed and without the shutter speed dial. When the dial was replaced the 'B' speed didn't work reliably again. I assume the extra weight of the dial was responsible.

Normally it's the addition of a film that causes them to play up, the intermittent type fault never rears its head till then. Not that FSUs are worse than any other make for misbehaving like this ONLY when film is loaded! You mend it, sit and fire the shutter repeatedly until you're happy it's fine - then load a film. Hmmm....

[fanshaw]

Thanks to all for your suggestions. I will try modifying the spring, first.
Wolves, in this case at least I didn't have the annoyance of a fault that occurred when I put film in the camera. I have had this experience however. I have a Zorki-5 with the desirable red logo which seems OK without film. Unfortunately when it is loaded the film exerts a sideways pull on the winding spindle which causes it to jam. I don't know whether there is something missing that should prevent the spindle from moving or whether the teeth in the winding mechanism are worn out.

Although some people are apparently able to open the tops of these cameras without mutilating the plain chrome ring in the centre of the winding lever I have not been successful, with this or any other camera with this design. It seems so uncharacteristic of KMZ to make something so difficult to remove!

[wolves3012]

Originally Posted by fanshaw

Wolves, in this case at least I didn't have the annoyance of a fault that occurred when I put film in the camera. I have had this experience however. I have a Zorki-5 with the desirable red logo which seems OK without film. Unfortunately when it is loaded the film exerts a sideways pull on the winding spindle which causes it to jam. I don't know whether there is something missing that should prevent the spindle from moving or whether the teeth in the winding mechanism are worn out.

Although some people are apparently able to open the tops of these cameras without mutilating the plain chrome ring in the centre of the winding lever I have not been successful, with this or any other camera with this design. It seems so uncharacteristic of KMZ to make something so difficult to remove!

Two areas to look at on the Zorki 5. One, is there sideways play on the bearing directly under the sprocket (hidden under the main flat spring)? That wears and eventually causes problems; I've bushed one of my Zorki 1s here to solve double-winding problems but it could cause those gears to jam too. Second, are the winder gears clean, lubricated and adjusted proerly? I can see the potential for misaligned gears to jame there too.

As for the retaining ring over the rewind, I've possibly been lucky. My Zorki 5 yielded fairly easily to a piece of rubber and pair of pliers. My Zorki 6 was a little more troublesome and took a few attempts. I think I had to use a small blowtorch on that, just for a few moments, to expand it a little. I agree it's not very clever. Now I have got into the habit of unscrewing them a little and finger-tightening them on the loose side of things. Doing that every couple of films ensures they don't get the chance to sieze again.

[fanshaw]

Originally Posted by wolves3012

Two areas to look at on the Zorki 5. One, is there sideways play on the bearing directly under the sprocket (hidden under the main flat spring)? That wears and eventually causes problems; I've bushed one of my Zorki 1s here to solve double-winding problems but it could cause those gears to jam too. Second, are the winder gears clean, lubricated and adjusted proerly? I can see the potential for misaligned gears to jame there too.

As for the retaining ring over the rewind, I've possibly been lucky. My Zorki 5 yielded fairly easily to a piece of rubber and pair of pliers. My Zorki 6 was a little more troublesome and took a few attempts. I think I had to use a small blowtorch on that, just for a few moments, to expand it a little. I agree it's not very clever. Now I have got into the habit of unscrewing them a little and finger-tightening them on the loose side of things. Doing that every couple of films ensures they don't get the chance to sieze again.

Thanks for the suggestions. I think the problem lies in the winding gears because if I apply sideways pressure with a finger to the winding shaft while winding on, winding tends to seize up. If I ever manage to get that ring off I will look at the gears, which I suspect may be damaged.
I never thought that I might have to invest in a blowtorch to repair one of these cameras!

[Ramon-uk]

I have recently had the "intermittent B" problem with an NKVD Fed1. This was caused by the non-return mechanism in the main cog below the winder knob. The spring was deformed and part of it had slipped out from under the cog.
Most times it worked ok but every now and again it allowed the winder knob to creep backwards when the shutter was cocked, this means that the nib on the shutter dial was slightly misplaced with the crescent shaped lever and therefore the second blind couldn't be held back. This fault appears more often when there is film in the camera because of the extra drag on the winder mechanism.
Now that the spring has been re-formed and refitted everything works perfectly.


Nib in correct position.




Slipped back from fully cocked because of winder spring fault.

[wolves3012]

I see yours has the hole for 1/1000th, mine has it too (I suspect they all did). Glad the problem is solved...enjoy the camera now.

[fanshaw]

Originally Posted by Ramon-uk

I have recently had the "intermittent B" problem with an NKVD Fed1. This was caused by the non-return mechanism in the main cog below the winder knob. The spring was deformed and part of it had slipped out from under the cog.
Most times it worked ok but every now and again it allowed the winder knob to creep backwards when the shutter was cocked, this means that the nib on the shutter dial was slightly misplaced with the crescent shaped lever and therefore the second blind couldn't be held back. This fault appears more often when there is film in the camera because of the extra drag on the winder mechanism.
Now that the spring has been re-formed and refitted everything works perfectly.

Interesting. There is obviously more than one cause for this fault since I have a Fed that has the fault and a perfectly working non-return spring. Also, the spring was replaced in the Fed-2 with a pawl device which is a better design, but these cameras are subject to the same problem.

[Peter_Jones]

A word on retensioning the spring - mine was a bit rustier than I thought and snapped ! Time to make a new one.

[afurcolin]

Hello everybody.
Sorry to revive this post, but i have the same issue im my zorki4.
All other speeds seems to work properly.I already shot a film and the exposures where ok. (except by the fact that the entire film was only half frame exposed, but i think that is another problem that i am trying to solve in this forum)
Initially the speed dial was missaligned and i corrected it.
It happened that the BULB mode worked some 6-10 times (iregularly) just after i got the camera and aligned the speed dial, but after that the bulb simply seems to work like 1/125 or even faster speed.
I still havent run the sticky post HOW TO:ZORKI CURTAIN TENSION because i cant find a CRT monitor or TV, but i am trying to find one.
Do you know where should i start? I think i shoudl solve this BULB issue before the half-frame issue,no?
Thank you all very much

[Ron (Netherlands)]

Originally Posted by fanshaw

I expect that some of you may have come across a fault that commonly occurs with Fed/Zorki shutters. The second curtain is not detained on the 'B' setting, intermittently, and you get something like 1/30 instead occasionally or often depending on the severity of the fault. I suppose it is due to wear of some component. I played with a Fed-2 and found that the shutter worked perfectly with the top removed and without the shutter speed dial. When the dial was replaced the 'B' speed didn't work reliably again. I assume the extra weight of the dial was responsible. Does this suggest changing shutter tension might cure the fault?

Make sure the latch (the hockey stick part) itself is clean, sometimes some grease has made it stick a little. Further the latch is influenced by the spring on top of it, but also by the spring at the bottom of the camera: the main shutter spring. If tensioning of the top spring doesn't work out, you could try changing the strength of the string attached at the bottom; sometimes these spring have been bent to much and making it difficult for the latch to come into position.

[afurcolin]

Originally Posted by Ramon-uk

I have recently had the "intermittent B" problem with an NKVD Fed1. This was caused by the non-return mechanism in the main cog below the winder knob. The spring was deformed and part of it had slipped out from under the cog.
Most times it worked ok but every now and again it allowed the winder knob to creep backwards when the shutter was cocked, this means that the nib on the shutter dial was slightly misplaced with the crescent shaped lever and therefore the second blind couldn't be held back. This fault appears more often when there is film in the camera because of the extra drag on the winder mechanism.
Now that the spring has been re-formed and refitted everything works perfectly.


Nib in correct position.




Slipped back from fully cocked because of winder spring fault.

hello ramon!
i have a unreliable shutter speed in my zorki 4...sometimes it works, sometimes not...
could you please upload the images again? they are off now...
would you explain how did you solve it? i tried to unterstand it but without the pictures and with my bad english i couldnt be able to fix mine...
thanks!