Mamiya SD (Copal) shutter sticking (hesitating) 1/4 and slower ...

[dmr]

I thought I would ask here before I go tearing this thing apart. ...

This is kinda strange. This is a Mamiya Super Deluxe rangefinder, ca 1960's, with a Copal SVE shutter, working perfectly for some time now --- except ...

At speeds 1/4 and slower, the shutter has started hesitating. It opens and I can hear the gears in the timer or governor or whatever you call it hesitate, and after several seconds it does shut.

At speeds 1/8 and faster, all seems normal. No hesitation at all, nice and perfectly smooth, and the shutter speeds seem sane.

What kinda baffles me is that it's such a radical difference between 1/8 and 1/4. I have another one for parts (alas, the shutter assembly is bent) and I can't see anything really different between the way it handles 1/8 and faster and the way it handles 1/4 and slower. Anybody know if it sets the timer or governor differently at these speeds?

Has anybody seen this before where 1/8 and above appear to be perfect, but 1/4 and slower stick or hesitate?

Thanks in advance, gang. 🙂

 

[Sonnar Brian]

This is typical with my Copal Shutter cameras. The slow-speed mechanism needs a flood cleaning. That has usually done the trick for mine. 1/4th will often free up with some exercise, but 1/2 and 1s always want a bath. Ronsonol usually works best for me, but the Lynx 14 wanted a stiff shot of Isopropyl Alchohol.

And I KNOW anyone who tore into a Canonet can handle her Isopropyl Alchohol!

 

[taffer]

Probably they are different speed trains for 1/8 and 1/4, or at 1/8 the springs still have enough force to 'push' the thing.

Sounds like the common sticky leaf shutter problem, a Copal shouldn't be more difficult to service than a Compur or a Prontor.

I think...

 

[dmr]

Thanks, gang. 🙂

I'm afraid I'm going to have to bite the bullet and take it apart. 🙁

I have taken the other one apart down to the shutter, so hopefully this one will go well. I rarely use 1/4 and slower, but if those are sticking, it probably should be cleaned.