FED 3B shutter question

[julio1fer]

I got locally a Fed 3B, in the perennial search for the cheap, ergonomic, functional LTM body.

The shutter fires at all speeds and seems correct for the fast ones (i.e. 1/30 and below) It works well in B as well. In the 1 second to 1/15 range, the shutter opens and the buzz is heard for the correct length of time, but the shutter remains open. A gentle tap in the side of the body makes it close.

Is there anything easy I should look for before starting full disassembly for a CLA?

Thanks for any advice! (and please don't tell me to buy a Leica, I already have one). 😛

 

[mooge]

anything easy? well, probably not. you're gonna have to take it apart... but a DIY CLA shouldn't be too difficult.

good luck!

 

[wolves3012]

The bad news is that the symptoms you've described are typical of a camera needing a proper CLA. The good news is, it's not too hard to do on a FED 3b!

It tends to be the slow speeds that give out first. From what you describe, the slow-speed escapement is failing to release the second curtain. There's a small cam under the escapement which pushes a tiny lever aside to release it. Either the escapement is gummed up or the lever is (or possibly the shutter mechanism is also stiff, or any combination of the three!).

 

[julio1fer]

Thanks for the comments - I'll get the tools ready and post back as soon as I find a few hours!

 

[julio1fer]

Well, I'm getting into the Fed-3B. My guides are Rick Oleson's Tech Notes and the excellent sticky thread above about cleaning the Zorki-4 (FED-3 and Zorki-4 are mechanically similar, or so I gather). As I can only work on the camera on weekends and for a couple of hours, this is going to take some time!

The camera is ugly but it has no dents, it seems to have stayed unused for many years. Front view, ready to start working into the shutter.

After inspection and making the shutter work in the slow speeds, it was clear that the second curtain was not being released as it should by the little cam below the slow speeds timer (blue arrow):

I'm not sure of the cause of this problem. The cam was sitting where it should and contacted the second curtain's catch in what seems the right place, but it could not move the catch; helping the gears in the direction of their normal movement did release the catch.

What could be the cause? Lack of adjustment, something bent, dirty timer gears, too little force of the spring in the timer? I took the timer out in order to take a closer look at the shutter release mechanism (I know I'm in for a lot of fun to put it back again):

In the picture above the shutter is set at 1/125, just to show the parts. The second curtain catch, pointed by the blue arrow, catches a black metal pawl (red arrow) in the rotating speed selector assembly. I'm surprised by the sharp look of the catch's end - is it normal? Moving the catch clockwise in order to release the second curtain, which is the cam's job, takes what seems to me quite a bit of force for these small mechanisms. Maybe curtain tension is too much; in any case it is balanced with the second curtain, or so it looks in TV tests.

Besides, I thought that with the timer out faster speeds should work normally, but they don't - the pawl is stopped by the second curtain's catch. Maybe the cam holds the catch in the right position only when the timer is in place?

Is there any adjustment to be made on the second curtain's catch (pointed by blue arrow in last picture) with the timer out?

My current plan is to clean the slow speeds timer in solvent, then install it again and see if it works. If not, I'll have to think harder.

Any comments are most welcome, and thanks for looking!

 

[wolves3012]

The faster speeds won't work with the timer escapement removed - the cam keeps the catch out of the way only when the timer has run down (in its "resting" position). I'd see how it goes after cleaning the escapement and I'd suggest that you oil it VERY sparingly with some thin clock oil. It's possible to increase the spring tension if it still fails to trip the 2nd curtain after this. There's not really any adjustment possible in the catch.

 

[julio1fer]

Slow speeds are now working, after soaking the slow speeds timer in solvent and installing it back. Thanks Wolves for the tip!

In order to install the timer I found it easier to set the shutter to 1/2 s, wind the gear, then install in such a way that the pin in the ring gear comes to rest with the top of the speed selector blade.

After installing the timer I found that fast speeds seemed to expose only about 3/4 of the frame. The right side, as seen from the back, was always dark. Besides, all speeds from 1/60 to 1/500 seemed to give the same illumination. It turned out that, when setting back the timer, the spring holding the B cam (just below the red arrow above) had come loose. Once fit in place again, all of the shutter speeds work fine.

Whew! Now, to consider more mundane affairs - leatherette, cleaning, viewfinder, RF... Am tempted to paint the top cover black...

 

[julio1fer]

The test roll had most of the pictures with their left hand side dark - here shown with a good one for comparison (both in the test roll):



Firing the shutter with the back out shows that often the right hand side of the film gate (i.e. left in the pictures) is indeed dark at the speeds used (1/500).

Any specific issue to look for? It is quite puzzling that sometimes the frames came out OK. Exposure (in the exposed area) seems correct and even.