Strange M6 problem

[edge100]

So I'm having a weird issue with my Wetzlar M6.

It was recently CLA'ed by Gerry Smith at Kindermann, and has been functioning well.

I've recently bought a bunch of 24-exp rolls of Fuji Superia 400, and EVERY time I load a roll of it, my M6 starts misbehaving. I load the film as normal, wind on, and then nearly every time I press the shutter, the camera fails to actually open the shutter. Sometimes it will work fine, sometimes the shutter wont actually fire until I take my finger off the shutter button, and sometimes it wont fire until I start to wind the frame. This happens at all shutter speeds.

What's odd is that if I dry fire the camera, it works perfectly. Similarly, I tried it with some Portra 400 and TMax 100, and there were no issues at all.

Any ideas what might be going on? I can't figure out why a particular film would be causing problems.

 

[Monochrom]

Hi, if it happened with only 1 kind of film cartridge it may be fouled at some point. And that batch may have the same. Try to compare hte cartridges with the ones that are working ok, perhaps some difference will pop up.

🙂

 

[Vickko]

The film advance and shutter cocking gear train is probably "one gear tooth off".

This gear train controls the shutter cocking, stops the film advance at the right place and winds on just enough film for proper spacing. It also controls and sets the interlock between properly advanced film and enabling the shutter to fire.

It is an easy adjustment as the gear that is necessary to "adjust" is loaded on a spring. You just pop it up, move the mating gear one tooth over, and you are done.

I think the designers at Leica knew that such an adjustment would be necessary.

And yes, dry firing the camera will be fine; it is the additional resistance and back-pressure caused by a roll of film that causes the exact behaviour that you describe. Taken to its worse-case, the camera won't even fire, due to the interlock.

 

[Highway 61]

The film advance and shutter cocking gear train is probably "one gear tooth off".

What he wrote. Now back to Kindermann so that this adjustment is done.

 

[35mmdelux]

You shouldn't have t tweak it after it was CLAd. Return it.

 

[edge100]

But why is this affecting only one type of film? That's the odd part.

 

[Vickko]

My guess is that the film that causes the problems is stiffer or causes more film tension, and the film without the problem is more flexible and doesn't offer as much back-tension.

 

[edge100]

Thanks, everyone. I'll be sending it back to Gerry at Kindermann on Monday.

 

[edge100]

UPDATE: Just picked the camera up from Gerry this morning, and it's good as new. Thanks, everyone, for all the help!