is my Sinar F1 back broken?

[Andrea Gazzoni]

I had this strange accident yesterday while shooting outdoors with my Sinar F1.
I was pulling the back assembly in order to insert the film holder and shoot when I heard a crack and the groundglass assembly just opened and detached itself from the back frame. No chance to have it reattached.

From what I understand the tab circled on the silver lever marked with A in the picture must lie under the B lever, but I don't know how to lift it.

Can someone using this kind of Sinar back post a picture of this part, so to confirm my idea?

Any advice on how to fix it without sending it to Sinar Assistance?

thank you
Andre

[Bjorn Nilsson]

Well, the B lever is acutally a leaf spring. But given that these two are both intact, i.e. of the same length etc. what you could try to do is to take out the small insex screws at the "foot" of the leaf spring B (to the left in both pictures) and then gently pry it back a centimeter or so. Then you fold back the locking lever A into the original position after which you have to get B back into position, now over (instead of under) A. Put back the insex screws and you're done.
What is strange is that this has happened in the first place. These springs are rather strong and should not just pop out of position. Just make sure nothing is cracked or broken and test the setup before you use it again.

//Björn

[Andrea Gazzoni]

Thank you Björn, do you have a picture of the same part so I can verify if anything's missing?

The screw you are suggesting to open is 1 or 2 in this picture?

Andre

[benrains]

The leaf springs "B" definitely need to go over the metal tabs you've circled on "A". The design of the rear frame on my meter back F2 is very similar, with one obvious difference. On my back, the ends of the leaf springs nearest those metal tabs are bent into hooks that wrap around the tabs. In your photograph it looks as though those ends of the leaf spring are either screwed into the frame of the ground-glass holder *or* they've something screwed into their ends that'll behave similarly to the hooked ends of my springs. (My guess would be that end–the right end of the spring in your photograph–isn't actually screwed to the frame though, because I can't imagine that would allow the springs to flex like they should.) You might see if you can pry up that end of the spring with a screwdriver or needle nose pliers to verify it's not attached to the frame. As for getting the spring back over the tab on "A", I'm not sure, but Björn's suggestion sounds reasonable to me. You might also be able to just flex the springs enough to get the tabs under it again without actually detaching the springs.

It's an odd sort of failure though, and at least looking at the hook ended springs on my back it doesn't even look like it'd be possible (at least not without either the spring or the metal tab on 'A' breaking.) But if on your version there is something screwed into that end of the spring to act like the hook does on mine, maybe it has become bent or it has broken off, allowing the tab to slip free of the spring when the bail mechanism is fully extended (?)

I think it should be an easy repair, but may have to send it in to get the two leaf springs replaced. My F2 is relatively new, and given the different design of the springs in mine, what happened to you might be a known problem that Sinar addressed with a design change in later models. (Just an educated guess.)

[Andrea Gazzoni]

thanks everyone guys, it really was an easy fix: as suggested by Björn all I had to do was to loosen the screw n°1 with a little allen key, sliding back the B lever, putting the A under B and finally tighten againg the screw.

final result and useful tool in the attachment, thank you again

andre

[Bjorn Nilsson]

Good thing that you sorted it out. (For once in a while we're enjoying really good weather here in Sweden, so I went out for the rest of the day, enjoying a very nice spring afternoon.)
I was about to suggest that you should take out the ground-glass while doing the repair, as the leaf springs seems snappy enough to cause a mis-hap of some kind.

//Björn