Sinar Shutter - Norma Version - Only firing on release of cable. Charge lever assembly not releasing tension ring assembly -VIDEO / SOLVED / now FIXED

[Flapper]

Hi all,

I've picked up an old Sinar Shutter (Old Norma Version). It only fires on release of the makeshift cable I'm using to test it (a wooden skewer).

I've opened it up. There's a hook on the Charge Lever Assembly that looks to me like it should reach a certain point on the Tension Ring Assembly and then release the TRA so that the shutter fires. Instead this CLA maintains its hook on the TRA until the cable is retracted. Then the shutter fires with seemingly slightly inaccurate speeds.
When I manually release the CLA with my finger the speeds look fine.

See here:

Video of the CLA interacting with the TRA

The piece on the CLA with the hook

The hook still catching the CLA with the TRA at full stretch

Does anyone know how to solve this. Am I looking in the wrong place?

Thanks. Sam

 

[Ian Grant]

It is only supposed to fire when the long throw cable release is used. First pressure sets the aperture, second cocks the shutter, and the shutter releases as soon as fully cocked the shutter. So effectively it's like a Press shutter

In the UK Linhof Studio sell a 3rd party long throw cable release that works perfectly. Bring it over tomorrow. I bought one in January for £20 at a camera fair, I assimed it was faulty, a visitor in April said hang on went to his car and came back his Sinar cable release and the shutter worked as it should

Ian

 

[Flapper]

I've figured it out.

The Charge Lever Assembly needs to strike a release roller at the end of its travel - this disconnects the CLA from Tension Ring Assembly and the shutter fires.

On my copy the release roller - parts 2-41. 2-42 and 2-43 are missing (it looks like they've broken off) : Missing Roller

See the attached screenshot from the service manual for the missing roller.

 

[Flapper]

I've fixed it - at least in the short term - by flooding a small plastic washer maybe 2mm deep by 3mm wide with epoxy resin glue in the place where the roller once stood. I left it to set for 2 hours.

On return it worked immediately with the Charge Level Assembly meeting the stop and disconnecting at the end of the stroke and firing the shutter. Very satisfying!

Then on the side that meets the Charge Level Assembly I've added a little grease to counter-act the stickyness of the expoxy.

I wonder if it will stand up to constant use, but with the price of sheet film, it's not going to get constant use!

 

[ComoDutch]

I've figured it out.

The Charge Lever Assembly needs to strike a release roller at the end of its travel - this disconnects the CLA from Tension Ring Assembly and the shutter fires.

On my copy the release roller - parts 2-41. 2-42 and 2-43 are missing (it looks like they've broken off) : Missing Roller

See the attached screenshot from the service manual for the missing roller.

Hi Flap, good problem solving! Do you have a copy of the service manual available to share?

Ps I just solved a sticky shutter issue for the same type shutter, turned out to be a dent in the plastic cover touching the front facing side. Can be a more common problem. 10 min work, shutter - purchased as faulty for very reasonable price - works like a charm.

Best, Erik

 

[Flapper]

Hi Flap, good problem solving! Do you have a copy of the service manual available to share?

Ps I just solved a sticky shutter issue for the same type shutter, turned out to be a dent in the plastic cover touching the front facing side. Can be a more common problem. 10 min work, shutter - purchased as faulty for very reasonable price - works like a charm.

Best, Erik

Hi. It's hosted here currently: https://www.galerie-photo.com/manuels/obturateur-db-sinar.pdf

Probably best to download it before it disappears.

 

[ComoDutch]

Many thanks for the link and document. Recommended for all Sinar shutter users! Erik