Arriflex 16 SRII Highspeed mirror suddenly shutter stopping in the closed position

[Matthew J. Walker]

After shooting with my SRII at 150 frames per second accompanied by some new unusual noise, I switched off the camera and noticed the mirror shutter had not stopped in the open position when the camera is powered off, but instead stopped closed. I'm unsure, but I may have forgotten to engage the roller on the take-up side of the coaxial magazine, which in the past has simply led to a jam, however the film that was shot seemed to have spooled normally upon removing the film from the magazine. I usually don't make mistakes like that but again, I'm unsure. Now as stated in the user manual, "each time the camera is switched off the quartz controlled motor stops the mirror shutter in such a position that the finder is open for viewing". This was always the case with my camera and suddenly this has changed. When looking through the film gate, light can be seen coming through the lens, however when looking through the viewfinder the mirror shutter appears closed. If I rotate the mirror shutter by hand, an image becomes visible through the viewfinder again but the film gate is covered by the mirror shutter. What exactly has happened?

Edited July 25, 2023 by Matthew J. Walker

[Dom Jaeger]

Sounds like the belt slipped. On SR1s and 2s the motor stops in a fixed position so the belt timing determines the parking position. Should be an easy job for a tech to reset, though the belt may need replacing if teeth have been stripped or it's simply deteriorated. 

[Matthew J. Walker]

5 hours ago, Dom Jaeger said:

Sounds like the belt slipped. On SR1s and 2s the motor stops in a fixed position so the belt timing determines the parking position. Should be an easy job for a tech to reset, though the belt may need replacing if teeth have been stripped or it's simply deteriorated. 

Thanks! Would running the camera in it’s current sate cause further issues or would you suggest not running it until  I bring the camera to a technician? Manually rotating the mirror shutter after each take would not be the worst thing in the world, however the last thing I’d want would be to cause any further mishaps or potential damage to any camera mechanisms.

[Dom Jaeger]

Yes I would err on the side of caution and have it checked before running it again. 

[Matthew J. Walker]

4 hours ago, Dom Jaeger said:

Yes I would err on the side of caution and have it checked before running it again. 

I'm bringing it to get checked out tomorrow, thanks Dom!

[Mark Dunn]

On 7/25/2023 at 6:56 AM, Matthew J. Walker said:

If I rotate the mirror shutter by hand, an image becomes visible through the viewfinder again but the film gate is covered by the mirror shutter.

You do have a fault, but this is normal. You only see through the viewfinder when the shutter is closed- that's how a mirror shutter works.

[Matthew J. Walker]

@Dom Jaeger You were correct. A tooth on the belt skipped which was causing the timing issue with the shutter. Very simple fix as you suggested. And @Mark Dunn the technician also confirmed to me that  it still would have been safe to run the camera with the skipped tooth. It’s all fixed now. Thanks guys.

Edited July 29, 2023 by Matthew J. Walker

[Dom Jaeger]

Thanks for the update Matthew, I’m glad you sorted it out.