Hello,
I've been on a bit of a journey with a beat-up 6x7 I got for free in a big lens purchase (the lenses were worth the entire purchase price). With a battery added, the mirror came free from half-cock and I was able to wind and both dry and "wet" fire the shutter. However, the frame counter was stuck at "8" from the moment I got it, and never advanced from there. I kind of wrote it off as a backup to my daily-driver 67 (which has its own issues; a missing meter chain and a chewed-up shutter speed wheel which means it can get stuck "between" shutter speeds and not fire correctly; still haven't mustered the courage to disassemble the shutter speed selector assembly myself, though I've had the cover off at least).
HOWEVER, I decided to take another crack at it recently and it is completely fixed! I wanted to document this fix online because it was a VERY SIMPLE problem that anyone with a fine flat-head screwdriver and a bit of nerve could solve.
So, again, let me explain the symptoms for the benefit of the reader, and to help people searching for answers:
- The frame counter was stuck
- The shutter would cock and fire
- but the frame counter would not advance when this was done
- The frame counter would not reset when the back was opened
The fix was literally accidental. worked up the nerve to remove the housing on the shutter, and so I took the first step (as far as I could see) of removing the cover of the frame counter by unscrewing the 3 grub screws around the edge of it. When I removed this cover, a black metal spring popped out, along with the frame advance "button" (the little knurled plastic button in the center, that you depress and turn with the back open to advance the frame counter for dry firing. Labeled "exposure counter handle" in the upcoming service manual.). In the excitement of that, it took me a little while to notice that
the frame counter had reset to zero.
I suspect that whoever had been in here last had reassembled the frame counter had done so clumsily (there were plenty of crude screwdriver marks around the set screws), or alternatively perhaps some part of the spring had bound on the frame counter. Regardless, the problem was fixed. I reassembled the pieces carefully, and reattached the cover and clamped the set screws back down, and the frame counter is now counting and resetting as it should.
The most scary part of this whole operation, and indeed probably the only truly scary part, is the microscopic grub screws. Please, for your own sanity, only back them off 1 or 2 turns at most, then see if you can lift the cover. You do NOT want to have to thread one of them back in the cover by hand with a cheap non-magnetized jeweler's screwdriver (ask me how I know!). I've attached a couple photos which make help in documenting the process. 0013 shows the bare frame counter, and 0014 shows the knob and spring replaced. I believe that 0014 actually depicts the spring upside down; I have since flipped the spring so that, at rest, it holds the knob up off the frame counter.
Part II: Service Manual
When I got my pentax 6x7 and 67, I had a hell of a time finding good service manuals and documentation. Given there are literally only a few guys in the world who are willing to work on these for money, and they all want quite large amounts of money to work on the cameras (not saying it isn't a fair price; they have a rare skill that's hard and expensive to acquire), I wanted to find a service manual or diagram to work from, to make working on the camera easier. It took me a good couple hours of chasing down dead links to find one. As such, I want to re-share that manual with you all, in the hope that it is easier to find in the future. I've uploaded it to archive.org, who are pretty good about keeping links around long-term, so hopefully in the year 2035 when we're still repairing our damn medium format film cameras because they're too much fun to use, people will be able to download it.
Here is the link:
Asahi Pentax 6x7 Service Manual : Asahi Opt. Co. Ltd. : Free Download, Borrow, and Streaming : Internet Archive (archive.org/details/pentax-6x7-camera-manual)
Originally posted by pentaxus 
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