Just purchased a Hasselblad 500c/m with A12 back. Was working just fine and then out of nowhere I was having troubles with the back. The film advance knob on the A12 keeps winding and winding but it's not advancing the frame counter. The '0' is half visible and stuck, and the window right next to it is neither white or red. When mated to the 500c/m (I have the 500 cocked before I place the A12 on) it fires; however, I am then unable to wind the film advance knob on the 500 again and I can't fire the shutter release as the colored dots on the 500 and A12 are not in sync. Any idea what the issue could be?
My initial though is if it's from a dealer tell them to give you another A-12 mag. If it's a private party, tell them to either get you another back or go back and tell them to take the back back...Jack. My second thought about this, if you can remove the mag from the body, is to test fire the body multiple times and advance or recock it and see if it happens without the mag on the body. That will help you isolate the problem to one or the other. If while the mag is attached, as you wind it it kicks the mag back slightly from the body, it's a gearing problem on the mag or the rear of the body. If it winds and sticks without kickback, it's in the winding mechanism itself on the body. Another way to test just the mag is wind it without attaching to the back. See if it feels smooth, with and without the darkslide in place and look to see if the flange on the rt. side of the mag that's turned by the body, stops in the same position each time you advance the magazine winder.. Sacrifice a roll of film and check the spacing with each frame advanced. Each frame should be about the same.
If it's just the mag, for example David Odess
http://www.david-odess.com/repair.html charges $90 to CLA an A-12. If it's the bod, $195. OTOH, a replacement/additional mag at KEH that comes with a reasonable warranty and replacement runs anywhere from $39 to $235.
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Spare mags are always really good to have as you've just discovered and gone are the days when used ones cost nearly as much as new. If you're on your own and have a repair shop in mind, I'd send the whole rig in for CLA. I say that because it's possibly the body gearing.
If you look at the back of the body, on the right you'll see the gear mechanism that couples with the mag. If that gearing is worn it'll cause the mag to either jam or skip frames. Just the same as worn gears on the mag will cause the body to jam. Hard to isolate even test firing and cocking the body without a spare mag that you know is good.
Nonetheless, welcome to the party. I'm sorry this happened to you right out of the gate. It's a truly great piece of equipment and actually remarkably durable. It's probably an easy fix but the labor is awfully pricey and don't try this at home. Light traps are easy. Mag and body gearing is a little different.
Take it light ;>)
Mark
