90mm 2.8 Elmarit (2374xxx) missing click stop

[paulk_cci]

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I picked up a lovely black 90mm 2.8 Elmarit, with a litle bit of fungus on the back of the front element for a very good price, but on arrival I also noticed it is missing it's "click stop" on the aperture/diaphragm.

 

I have in the meantime opened the lens and managed to clean the haze/fungus very nicely, no etching on the lens and it cleaned off 100%.

 

But I am a bit puzzled as to how to fix the click stop? I have studied very carefully the diafragm blades and everything around it, and everyrhing seems to work exactly as it should, but I can't figure out how the "click stop' should work, let alone fix it. Is it operated by a small ball bearing, that somehow went missing during the previous owner's care, or am I overlooking something simple.

 

There was a round brass flat pressure ring lying on top of the metal grooved plate that moves the diaphragm blades in synchrony, when I screwed off the front lens element. However, I fail to see what that ring would be doing.

 

Anyone any ideas?

[adan]

The roughly contemporary 135 Tele-Elmars DID use a ball bearing for the aperture "clicks." I had a TE also missing the clicks about 8 years ago and John van Stelton at the Focal Point in Superior, CO replaced it.

[paulk_cci]

thanks Andy,

 

Well, we've made a bit more progress. Turns out the "click stop mechanism" has to be tackled from the rear.

 

You can unscrew the lens element of the Elmarit for use on the visoflex, so looking from the front into the aperture blades, didn't give me any clues as to how the click stopping would work, so I went at it from the rear.

 

Using a two pointed tool, I unscrewed the rear bezel, and that allowed to remove the bezel that has the white dot pointers on it, to mark the aperture setting, after which I could drop the actual aperture ring (after removing the two smal screws in the aperture ring. Luckily the blades themselves, though loose, stay nicely in place wedging themselves nicely at f:11 .

Now the inside of this aperture ring contained a tiny ball bearing sitting in an recess on the one side of the ring, and on the opposite side I can see the small rescesses that the ball "clicks" against. On the barrel where the aperture ring sits against, is a tiny hole with a spring in, so it seems ALL parts are there!!! but somehow the ball is no longer in the hole with the spring, but ended up on the other side in the recess.

 

It's almost as if Leica has provided for a recess for those people who like no click stops for the ball to be kept, and if someone wants click stops, the lens has the neccessary ball bearing that can be put into place.

 

My problem now is, that I see no way to press the ball onto the spring, so that the ring slips into place. With a tiny bit of vaseline, the ball rests on top of the spring, but when I slde the aperture ring over the barrel, it simply won't push the small ball into hole on its own...

Anyone with a bright idea would be helpfull :-)

[paulk_cci]

Eureka!!

 

I suddenly had a bright spark myself:

 

Using something as simple as a strip of normal cellotape. I taped it over the ball bearing sitting on top of the spring, and place the aperture ring on the barrel with the recess (where the ball was resting when I opened it up) at the position of the ball bearing.

 

Where normally the ball would remain in the recess and turn with the aperture ring, now the cellotape held the ball in postion over the spring, and when I turned the aperture ring now, it would actually be pushed into the spring and after turning the aperture ring 180 degrees, presto, I could hear and feel the ball click stop its way through the small recesses!! I was able to carefully pull the cellotape from under the aperture ring.

 

Now it was just a matter of carefully aligning the aperture ring and the diafragm blades, so that when the clickstop would rest a 2.8, the blades would be wide open, and then screw the two screws in the aperture ring again.

 

Putting it all together was easy, and I now have a fully "click stopping" Elmarit again.

 

Carefully analysing and "thinking before doing" got me a long way.

[jc_braconi]

Congratulations, sometimes writing the problem will gives the solution....