Half pressing button doesn't fire shutter on Fuji GL690

[AveryMiller]

Hey there! Had a bit of trouble trying to figure out what to title this, so let me explain.
I've been having an issue with my GL690 where frames are randomly missing. Sometimes every shot would be on the roll, other times only two. I finally figured out the cause: if I lightly press the shutter button down (about half way) there is a small click: the shutter doesn't fire, but the film advance mechanism unlocks. I'm able to advance to the next frame without firing the camera.
I'm really relieved to know what I've been doing wrong, but I'm curious if this is expected behavior? I haven't heard of anything like this before, but not fulling clicking the shutter button is such a silly thing to do it might have not warranted mentioning
Let me know if you have any thoughts on this, and thanks!

 

[reddesert]

The Fuji G690 / GL690 cameras with interchangeable lenses fire the shutter in the lens with a linkage using a lever in the mount. If you have the lens off you can see this lever move as you push the shutter button.

Due to years of use and possible wear in either the linkage or the lens mount, it is possible that the shutter might not fire at exactly the same time as the wind lock is released. There is an adjustment for the travel of the shutter-firing link, which is described in the service manual and relatively easy to access, so I assume it was something that could be adjusted during routine maintenance.

I described the link and showed photos in this thread: https://www.photrio.com/forum/threads/fuji-g690-shutter-linkage-question.172654/#post-2251639 where I had a camera that sometimes did not fire the shutter at all. Unfortunately, nobody was able or willing to measure the intended travel of the shutter linkage, but I was able to adjust my camera so it worked. If you adjust the travel too far, then it interferes with the lens mounting (Fuji could have engineered that a little better). If you don't feel comfortable messing with it, then just remember to press the button fully.

 

[Huss]

Lomo LC-A 120 does the same thing. If you half press then release it unlocks the advance and then you have to advance it if you want to take a pic.

 

[AveryMiller]

The Fuji G690 / GL690 cameras with interchangeable lenses fire the shutter in the lens with a linkage using a lever in the mount. If you have the lens off you can see this lever move as you push the shutter button.

Due to years of use and possible wear in either the linkage or the lens mount, it is possible that the shutter might not fire at exactly the same time as the wind lock is released. There is an adjustment for the travel of the shutter-firing link, which is described in the service manual and relatively easy to access, so I assume it was something that could be adjusted during routine maintenance.

I described the link and showed photos in this thread: https://www.photrio.com/forum/threads/fuji-g690-shutter-linkage-question.172654/#post-2251639 where I had a camera that sometimes did not fire the shutter at all. Unfortunately, nobody was able or willing to measure the intended travel of the shutter linkage, but I was able to adjust my camera so it worked. If you adjust the travel too far, then it interferes with the lens mounting (Fuji could have engineered that a little better). If you don't feel comfortable messing with it, then just remember to press the button fully.

I'm sorry to bump this post but I thought I already replied to this, but I guess not:
Thank you so much!! That makes a lot of sense, and I'm so glad the fix isn't too complicated.
Appreciate the help!