YF … GO … eh, no SLOW

One issue that I had with the camera after I replaced the ribbons was the slow speeds. Some of the higher slow speeds where OK, but hitting the slow speeds was a problem as it sometimes did not work.

The speeds 1/60 and higher are controlled by the timing of the second curtain release. The lower speeds are controlled by a slow speed escapement that is sitting on top of the bottom of the camera.

A separate speed dial changes the position of a swinging shaft that engages the slow speed escapement. The shaft is rotated by the movement of the second curtain roller, and thus turns the slow speed escapement.

Many Leica copy camera’s followed this Barnack design.

A flat spring on the bottom of the camera raises/lowers the shaft. When the top speed dial is set to 30X the spring on the bottom gets triggered when the shutter is open … it will push the shaft upwards. The top of the swinging shaft there is an arm attached that engages an tooth on the second curtain roller (shutter speed dial post) that is rotating by the roller movement.

When the shutter is released a flat spring on the bottom of the camera is pushed upwards … which raises the swinging shaft arm so that it can engage the tooth … which will push against it, thus induce rotation that moves the gears in the slow speed escapement.

The illustration is a bit incorrect, as the tooth is hidden under the larger arm that you can see.

The arm on top of the shaft changes position as the slow speed dial is changed. I didn’t take a picture of the back of the dial, but it has a ring that pushes against the swinging shaft, and also connects to the slow speed escapement to run only the star wheel (for 1/8-1/30s).

After the shutter release is completed the flat spring is lowered, the swinging shaft drops down and the top arm can no longer interfere when the shutter speed post arm.

OK, now that I explained that I will make mention of the issue that was located that caused issues with the slow speeds … as I noted in my previous post I already did some repair and cleaning of the slow speed escapement, so that should not have been the problem.

Looking at the metal arm plate attached to the top of the slow speed shaft I can see the leading edge is worn down.

I suspect that when the swinging shaft was in its lowest position (slow speed not engages) that top plate encountered the speed dial when it rotated … this eventually wore down the metal so it no longer had a 90 degree edge … so this causes it to slip over instead of engaging it when the slow speed are being used.

To fix that problem I reshaped the flat spring on the bottom of the camera a bit to ensure that the shaft lays lowest when not used … flattened the metal plate on top of the shaft so it was parallel with the top (it was lifted slightly at the end so I am guessing it was constantly being shaved down when the tooth returned position), and then I lightly (did not want to remove too much material) filed the side of the metal arm and tooth to get rid of any “ramp” … make a sharper edge at the tip.

After all that the speed dial arm was more consistently engaging the slow speed shaft plate at all low speeds … the most sensitive to this arm/tooth connection appears to be 1/4s.

[Missing picture, sorry forgot to take one] To adjust the timing, unscrew the cover of the slow speed dial. Here there is a centre screw and an outer ring. Loosening the ring and turning the inner screw will change the position a cam that is pushed against the swinging shaft.

This slow speed mechanism is a common setup on the typical Barnack type cameras, so you can read up on a Leica III repair and get similar info.

Gutta get somma dat sap.

One thing that I keep encountering is bellows … well, that kinda happens when you buy a lot of folders. Now because of their age, the bellows tend to have worn material especially on the top folds were most of the wear’n tear tends to be.

The best solution would be to replace the bellows, but sometimes it is not practical … so many would try to patch the holes. I have one Isolette where the last owner used some sort of plastic “tape” material to patch up each corner … which now after some years has become brittle and is cracking off. This level of damage requires a replacement, but most of the time they are pin holes.

Ok, so search for a product that can “repair” the smaller holes but still be flexible enough to allow the bellows to move freely … my first thought was liquid electrical tape, but after trying some of that on some actual electrical wiring I realized that it will harden and become a bit stiff after time and can flake off with continuous movement.

Sooo, after surfing the web I found someone who tried Gutta (though they never followed up to say how it worked after their initial post) … so I decided to give it a shot, I bought a bottle of Jacquard Gutta Resist black.

Gutta-percha … so what is it? It’s a tree, and also refers to it’s sap. Joon Ian Wong wrote a great write up on the history of Gutta Percha. Today it is primary used by people who are painting on fabrics, especially silk. It penetrates fabric and forms a barrier to keep dye from spreading.

So I have been trying it … and so far it works great, pinholes are gone. It remains rubbery (unlike liquid electrical tape that stiffens) so it flexes with the bellows so it should not crack.

It should be used on the inside worn out areas, as it works best on a fabric surface that can absorb it … does not like to be coated on directly on the outside leather as it cannot be absorbed by the material. Apply multiple layers, and let dry in between coatings.

I let the bellows dry for a couple of days before testing closing/opening … no sticking of the Gutta, and the pinholes remained sealed even on the long folds on top that were really worn on the outside. I closed up the bellows and let them sit for a week … openend it up and no sticking.

… so now I need to make a 90 degree paint brush to make it easier to get into the corners.

YF shutter … Barnack!!!

So … yet again I got this camera because it was listed as For Parts or Repair. The shutter was listed as not working properly. Visually I can see one of the ribbons is not secured as the curtain had a diagonal wrinkle.

Once I got it, I also noted the slow speeds don’t sound right … the advance lever was loose … a little cloudy looking through the viewfinder … the rest of the camera needed a cleaning … but the lens was in almost perfect condition.

With these cloth shutters, over time, the material starts breaking down or the glue that is holding them becomes old and brittle … so they have to be replaced.

OK, so you need to get some shutter curtain replacement material … you can get curtain material and ribbon/tape from a number of sources … I got some from Aki Asahi.

I have done this before on a Barnack type cameraa … it was not a pleasant experience replacing/fixing shutters … and know I will have to do this again … and it still will not be pleasant. Thankfully the mechanisms are similar enough to use other guides, like for Leica Barnack models.

To give you a prep … Richard Haw has a nice write up on repairing a Nicca IIIS, including a shutter curtain replacement … and you can also watch Nobbysparrow with a Leica … and of course, info on Rick Oleson’s page (there is a doc by Christopher Kuni on a shutter replacement)

Lets get inside … you will need screwdrivers, and a flexiclamp.

First thing is to take of the bottom cover … then remove the takeup spool … and then back hinged door (Yashica was nice enough to make it removable).

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The lens mount ring comes off by removing the four large screws … mark the top … when lifting of the ring keep an eye out for any shims underneath.

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Like a typical Barnack the front, side, back is one big oval shaped piece of metal that just slides off. With the Yashica YF you do not need to take the slow shutter speed dial off.

Take out the two large obvious screws on the body … the third one is hidden under the mounting ring.

Slide off the outer case by pulling it downward. You will find that the leatherette in the top corners is attached to the plate under it, so you will need to do some  work loosening it.

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The square plate on the front is covering the internals. There are six screws, around the outside, holding it. The sneeky one is at the top on the mounting ring at 11’oclock.

The four smaller screws around the mounting ring are holding the internal light baffle. You can unscrew them or leave them to keep the baffle attached … you will find out whether you like it removed or not.

You will need to hold down focus wheel while pulling the plate off. Lift from bottom and pull down and out (if you left the baffle on you will need to do some wiggling.)

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Sooo, now you can see the rollers and also the slow speed mechanism … and the top right missing an attached ribbon.

You can remove the slow speed mechanism by two screws on the bottom of the camera. On the bottom of the camera there is a black metal plate (which I removed early on)that is protecting stuff, remove the two screws to reveal what’s under there.

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There are three large black screws … two of them are what we are after, the ones holding the slow speed are on the centre and first top right (the one under the wire).

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You can take this and drop it in your ultrasonic cleaner … mine looked much shinier after some sonic.

I noticed that after a cleaning, it was sticking a bit. I found that the two screws were not tight so the gears could slip out of the “holes” … hmm, should have checked that first before.

If you have some watch oil you can put a tiny bit on the gear pinion holes (not on the gears).

Going back to that ribbon issue …

You can see in one of the previous images that the shutter curtain ribbon tape is not attached to the top of the roller on the right. Typically what you will find is a piece is still attached to the roller and the rest has broken off.

If you are lucky to have it just slip off the roller (because the glue has degraded) then you can just proceed to glue it back on … turn the roller to match up where the other ribbon is … glue and hopefully you do not need to re-adjust (in my case I had to reposition a couple of times).

If you need to do more than simple single ribbon … While I was working on this dissection I noticed that the ribbon for the other curtain was slightly torn … so now I will just remove and replace all four … luckily the curtains are good and still secure.

rollertension

On the bottom of the the camera … the right side show a couple of toothed nuts and pawls. These two control the spring tension of the two rollers above it. The top one is for the second curtain roller.

There are three components to this … the toothed nut, the centre screw (this is attached to the spring within the roller), and the pawl/cog. The pawl/cog is spring loaded and keeps the toothed nut from turning.

If you have a good shutter speed tester then you can Release The Kraken! Ok, that was not a very good movie, but a great catchphrase … what you can do is to free the spring load, and then later on with the shutter tester you can bring it back.

Release the pawl, then loosen the centre screw anti-clockwise … then turn the toothed nut and centre screw clockwise … you will feel the centre screw trying to turn by the spring loaded roller … let it all turn clockwise to remove the loading. This makes it easier to work with the roller when you are reattaching the shutter curtains or ribbon tape.

In the below image I have removed the top plate so I can remove the slow speed swinging shaft for more access … and also to reshape the little plate on the top that is pushed to turn the slow speed escapement. Removing the top will also give you some more room to work with.

Ok that arm … lift spring, lift arm, remove washers, then pull up and out the arm.

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Carefully remove the broken ribbon tape (you may find that the end attached to the curtain bar is sewed on with a single thread). When removing piece attached to the roller, you may want to make a mark on the roller where the end of the ribbon is.

Make a new ribbon tape. Create the looped end first, then measure and cut the required length. The ribbon is 3mm in width and 80mm in length … I used about 7mm to form the loop so I cut an 90mm length. On this camera all the ribbons are the same length for both curtains.

So, make a loop for the lathe. Secure the looped ends to the lathes with glue, and let them set before going on further.

Second curtain attached first … that’s the one on the right.

Feed the ribbon through … use some paper and feed it through first then attach the ribbon with some painters tape to it … then pull on through.

The shutter should be in its released state (if not, trip the shutter and manually rotate the left roller).

Start winding the advance just to enough to see the edges of both shutters. Look at the position of the two curtains, they should overlap a bit … Leica has a 3mm overlap, which I noticed on this curtain is where the stitching is. I lined up the second curtain (the left one) so it is sitting over the first curtain (the right one) up to the stitches.

Temporarily (tape) attach the ends of ribbons to the top and bottom pickup areas then wind up the shutter and check if it is parallel with the left edge of the frame, and also passes the edge to cover the window … when shutter is released manually turn the right side roller to see if the shutter is still parallel and also passes that edge of the frame window … make adjustments.

When you are happy, glue it.

Let is set, then you can put back some tension on the roller using the lower tension roller screw … then wind and fire the shutter.

Now for the first curtain … the left one. Feed the ribbon through, then wind up the shutter.

Look at the pallet control gear with the pin that is engaging the roller on the bottom. This has to be set in the correct position.

The illustration shows a Leica, with the pin just barely contacting the pallet lever. Turn the roller so that it is in this just before this position … put the slow speed escapement back in to verify … the gap is in anticipation when tension is put on the roller that it will move towards the lever after gluing.

Glue the ribbon on the roller, and let it set. Then you can add tension to that roller … make sure the pallet control gear does not push the pallet lever.

If you want to remove the pallet control gear and reposition it (without having to change the roller position and then having to reglue the ribbon on the roller), you will need a 90degree screw driver to loosen it.

I don’t have one … but I do have a couple of Ikea hex keys that have 90 degree ends, and a Dremel with a grinding wheel. Grind the other end perpendicular.

Set the shutter to the highest speed and make sure you can see some light through the curtain … the next part is adjustments to get the exposure time correct.

With the shutter in its released position, take all the tension out of both rollers.

Ok, so remember the top one is the first (opening) and the bottom one is the second (closing) curtain.

You will need three hands … OK, you can get it done with just two. Taking some info from a Leica how-to …

Start with the second curtain, by turning the center screw clockwise 1-3/4 turns and then release and turn the toothed nut to lock it in place.

With the first curtain, you turn the centre screw 3 turns.

Wind up and look through the shutter to make sure you are seeing light between the curtains at high speed. If you are not, then add tension to the first curtain roller.

Check the lower (~1/30s) speeds. The second curtain tension does have an affect on the force applied to the slow speed governor.

To check the accuracy of the speeds you should use a tester.

The adventures of this guy who tries to restore and repair vintage photographic equipment … and wins (most of the time).

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