Leica M3 high speed capping

[redtec989]

Hello, as you may be aware I started a thread not long ago regarding a jammed Leica M3 single stroke. Good news, I unjammed it, some gears had moved out of position, it is now working ok.

I took the time to clean and lubricate the slow speed mechanism. Now speeds from 1 second all the way to 1/125th second are fine, however 250, 500 and 1000 seem to be exhibiting severe capping. Releasing the shutter at these speeds shows only a small band of light at the begining of the frame as if the second curtain is overtaking the first curtain within 0.5cm of travel. On 1/1000 the shutter doesnt even have an opening at all. Could this be a matter of old lubrication? Or prehaps incorrect curtain spring tension? I've come this far in repairing the camera so as long as the adjustment is fairly simple I will attempt it myself. Any helpful info appreciated!

Thanks,
Alex

 

[ForestCap]

If you release the shutter at B and observe the shutter curtains, you should be able to tell if they travel more or less at the same speed. I mean if it's capping even at 250, you should be able to notice the second curtain (closing curtain) travels much faster than the first one (opening curtain).

If the second curtain travels indeed much faster than the first one, you can try to either reduce the tension of the second curtain or increase the tension of first curtain.

 

[rick oleson]

My first response would normally be cleaning and lubrication, which are always to be confirmed before making any adjustments. However, your comment about gears being out of position makes me wonder if they could possibly be meshed incorrectly and causing the curtains to misbehave.

A difference in velocity between the opening and closing curtains, though, is nearly always a function of cleaning and lubrication unless the spring tension settings have been tampered with.

If you happen to have an old working CRT monitor or TV lying around, you can use that to easily observe the relative speeds of the 2 curtains.

rick

 

[redtec989]

Thanks for your advice. I lubricated the shutter bearings and high speed cam and also exercised the shutter considerably, and the problem has now cleared up. Today I reassebled the camera and appears to be functioning well. I will put some film through it asap. Thanks for your help guys!