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Old 15th August 2010, 12:22 PM
Kev M Kev M is offline
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Default Bronica film back repairs

About a year or more back I bought a 645 film back form someone which didn't work properly, I can't remember if the film counter didn't work or if it didn't wind the film on or both.

Anyway, I started taking it apart but couldn't get one screw out so I put it back on the shelf. Yesterday I decided to drill the screw out and steal one from my 220 film back that I don't use. Turns out the reason I couldn't get the screw out was because it has a left hand thread instead of a right hand thread. Luckily I found this before I drilled the screw out.

So the problem is there are two circular plates under the film counter which sit on top of each other, one is fixed to the film counter and the other is meant to be free to rotate a little. Each has a set of groves cut into it's edge which overlap and there is a separate lever which sits in the grove preventing the film counter from rotating. When the shutter fires the lever retracts from the groves and the free plate is meant to rotate so that the groves don't over lap, it does this under the tension of a very tiny spring. As the film is wound on the film counter and the fixed plate rotate around until it catches up with the free plate and the groves line up. At this point the lever engages with the grooves and locks the film off ready for the next shot. The problem is that the free plate is sticking and so sometimes when the shutter fire the grooves stay lined up and the lever goes into the same position. This means the film doesn't advance and so you end up shooting over the same bit of film.

I've separated the plates and there was a bit of oxidisation on one of them which could have been causing the friction. Alternatively the spring might have lost some of its tension over time.

Do you think these plates should be lubricated or should they be dry? If they should be oiled what sort of oil would you recommend?

Alternatively, is there anywhere I can get Bronica spares from?

These things really are a work of art you know, proper engineering excellence (relatively speaking, it's a camera not a space shuttle)
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Old 15th August 2010, 09:20 PM
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Larry Larry is offline
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Hi and good evening Kev_M,

Sorry, but I can't advise you on your problem but it may be useful in speaking with: http://www.intro2020.co.uk/pages/service.htm

They were the UK importer and distributor for Bronica/Tamron and still do have a service department repairing Bronica equipment. There are very professional and I'm sure they can you give you some advice on the best way forward with your problem. It's worth a call at least!

best wishes
Larry (a Nikon and Bronica user).

Last edited by Larry; 15th August 2010 at 09:23 PM. Reason: missing word
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Old 16th August 2010, 08:01 AM
Kev M Kev M is offline
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Thanks Larry.

I think I've got it sorted now, I put it back together and slackened a couple of screws just to the point where the plate was moving reliably. I'll give Intro2020 a call just in case they've got some spare plates and springs in case it fails again.

Thanks for the info,
Kev
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Old 16th August 2010, 08:29 AM
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Steve Smith Steve Smith is offline
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Quote:
Originally Posted by Kev M View Post
These things really are a work of art you know, proper engineering excellence (relatively speaking, it's a camera not a space shuttle)
I expect they explode less often too!

Pleased to hear you have got yours sorted. I was going to offer you my spare 120 back which needs a new screw for the wind on lever on the end of the take up spool.


Steev.
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Old 16th August 2010, 10:15 AM
Kev M Kev M is offline
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Cheers for the offer Steve. If you send me a picture of the screw you need you can have the one off of my 220 back. Seeing as I can't get 220 film any more it's just a shelf ornament. It sounds like the one with the left handed thread that I had problems with. If it is then the problem is you can't nick one from elsewhere on the back as it's the only left handed screw I've come across so far.
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Old 16th August 2010, 10:24 AM
Paulographic Paulographic is offline
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I've a 6x4.5 220 back (and some Tri-X 320 in 220 left in the fridge),
which works Ok with 120 film just winds on tighter.
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Old 20th August 2010, 10:08 AM
Kev M Kev M is offline
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Has anyone got one that they could post a a few photos of the internals of? I seem to have a bit of plastic and two screws left over from when I took mine apart
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Old 20th August 2010, 10:26 AM
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Quote:
Originally Posted by Kev M View Post
Has anyone got one that they could post a a few photos of the internals of? I seem to have a bit of plastic and two screws left over from when I took mine apart
But does it still work?......


Steve.
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Old 20th August 2010, 12:16 PM
Kev M Kev M is offline
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Mechanically it seems fine (for the time being). I've run a spare roll through it a few times with the side cover off and the film counter is now working again and the film is advancing.

I'm a bit wary of trusting it with a proper roll of film though to take some pictures until I figure out where this bit of plastic should go.

Story of my life this, start something, get distracted, come back to it several months later and can't remember what I was doing in the first place.
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Old 20th August 2010, 12:25 PM
Dave miller Dave miller is offline
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Quote:
Originally Posted by Kev M View Post
Mechanically it seems fine (for the time being). I've run a spare roll through it a few times with the side cover off and the film counter is now working again and the film is advancing.

I'm a bit wary of trusting it with a proper roll of film though to take some pictures until I figure out where this bit of plastic should go.

Story of my life this, start something, get distracted, come back to it several months later and can't remember what I was doing in the first place.
The "several months" suggests that there is some hope for you. The time to worry is when the interval gets down to minutes.

Now, what was I going to do?
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Dave
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