After film testing my Tower 43, I was getting pictures back from the Lab that the frames were only half exposed and with an obvious hunk of broken film wedged in the area between the image aperture and the pressure plate. It was possible that the film piece was fouling the shutter curtains, so after removing the film piece I tried another roll but got the same results, just not as bad.
After doing some research and advice from forum friends I decided to tear it down to see if there was a small piece of film lodged in the curtain area somewhere or if it was just needing an adjust.
I got it opened up and couldn’t find any film pieces lodged anywhere so I decided to brave adjusting the curtain tension. I read a couple Leica curtain replacement instructions online and after holding it up to a florescent light at 1/500, I could see only partial opening of the shutter.
The following Set is the method I used to adjust the curtain spring tension. I assumed you could simply turn the sprocketed wheel to tighten the spring but after just a slight turn it seized up.
What you’ve got to do is release the Pawl, back off the sprocket nut clockwise a little and then turn the center screw counter clockwise to tighten the spring, hold it there while turning the sprocket nut counter clockwise, this puts tension on the center screw preventing it from spinning loose.
This worked finally and an added bonus to this repair is, I now have use of my slow speeds which I didn’t have before!
See the entire repair with step by step photos at my Flickr site