Hasselblad A12 back sticking

Discussion in 'Medium Format' started by matthew_delphenich, Feb 16, 2010.

  1. I recently bought a Hasselblad 501C with two A12 backs. The body, lens, and one back are in great condition but the second back seems to have an issue with sticking. As far as I can tell, there is a pressure spring next to the take-up reel, which is designed to keep the film tight on the plastic spool. In my back, however, the spring seems to be bent somehow, in such a way that after 9 or 10 exposures, the pressure it puts on the take-up spool is too great to continue to wind the camera (as evident in the second picture, the spring is already pushing against the empty spool). Since the other back I have is of a different design (it has spring-loaded buttons instead), I have no way of knowing what "normal" should look like regarding the spring. I think that I have narrowed down the culprit, but I wanted to see if anyone had any ideas about how much this would cost to get fixed, or whether there is something simple i can do myself? The seller from whom I bought it seems very willing to take care of any repairs I may need, but if this is relatively inexpensive, I would rather save us both the trouble and have it done locally. Thanks in advance!
  2. If your back is like mine, that spring should not curl like that. Here's how mine looks:
  3. Illustration 2:
  4. I've never seen a tension spring bent like that. Mine look like Bengt's, or a plunger style. This looks like a "home solution" gone bad. There are probably other issues as well. Either send it back to the seller, or have a factory repair and CLA performed on it (not a bad idea for any used back).
  5. Matthew, it's an "Ainryght" back presure spring.
    Translation: "It ain't right"
  6. Man, that piece of steel is bent all to hell. There should be a gentle curve to it. That needs to be totally replaced, there is no fixing it. You would almost be better off removing it rather than having it look like that
    Here are my two A-16 backs, one older and one newer style. As you can see on the left, it should have a nice gentle curve to it, not all bent up like the one in your back. And Bengt, yours looks pretty bent up too.
  7. As has already been written, the spring is badly distorted and must be replaced. This is something that you can do yourself, as it is only held in place with 2 or 3 screws, depending on the age of the film magazine. The part number for the spring is 12769. If you live in the United States, you can order this part from Hasselblad USA in New Jersey. Their telephone number is (973) 227-7320. Ask to speak with Nicole at extension 238.
  8. Thanks everyone for your help here. Bengt the spring you show is the one on the other spool, and on mine, that seems to be the proper shape (with the small downward curve at the end). Scott, your photo was exactly what I needed to see. I really think "bent all to hell" is an accurate description of mine. And David, thanks so much for all of your suggestions. I was actually planning to pay you a visit if this wasn't something I could do myself. I'll certainly do so if it's called for in the future!
    I'll order the replacement spring immediately, but is there any reason why it would be unwise to use the back without the spring in the mean time? If the pressure it puts on the spool is truly necessary I can wait, but it would certainly be nice to have two (mostly) working backs until the part arrives! Thanks again everybody.
  9. The spring is there to keep the film from unraveling once the trailing leader is clear of the pressure plate. You might need to unload in a changing bag.
  10. You are right, Matthew. Sorry about that - my bad. Just checked and the correct spring looks like Scott's... :)
  11. Scott Murphy , is right, that tension sprink is totally bent.
    The best idea, if you look at the top of the sprink holding 2 screwos, open them, remove the sprink, heat it up and try getting it to its normal position.

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