GX 680 - Batteries in the film back

Discussion in 'Medium Format' started by john_cullen|1, Aug 14, 2008.

  1. Greetings to all:

    I want to purchase a GX 680 and was wondering if the batteries in the film back power anything other than the
    LED? I would assume that the battery pack in the camera runs the motor, meter, etc. I also understand that the
    batteries in the back are not easily replaced. If all they power is the LED, then one could, I presume, continue
    using the back. Any information and/or comments would be most welcome. Thanks in advance for your help.
     
  2. I bought a set a few months ago. As far as my experience goes, the battery in the magazine onlu powers the lcd when the back is off the camera. When mounted on the camera, I have the strong impression that the battery in the camera powers the back, including the lcd. However, the batteries in both my backs still work so I am only 99% sure of this.
     
  3. I just acquired a Fuji GX680 outfit with one standard 6x8 back. The battery was exhausted and I found out that after detaching the back from camera you loose your count of taken frames. This does not happen immediately, but after a while. The battery must definitely be replaced.

    Fortunately this is easy: You just remove six visible cross head screws of the cover and also sensitivity selector knob. Removing the knob requires some kind of friction tool (thumb!) to open the flat head screw in the middle.
    After this the cover comes off easily. You can not miss the battery which is standard 3,6 volt lithium battery, size 1/2AA with wires for soldering. Soldering lugs are fully accessible and re- soldering very easy. The battery is available in every well- equipped electronics store. Just be careful to get the 3,6 V version, same size is available as 3,0 V version also.

    Naturally you need to have some basic skills in fine mechanics and soldering and trying this repair is on your own risk. For me it worked!
     
  4. Thanks Frank and Matti for your kind response and the information. I appreciate the time you took to respond
    very much and wish you both the best of luck. I look forward someday to possibly returning the favor. Best -
    John
     
  5. Matti Lietepohja wrote (some time ago): "Fortunately this is easy: You just remove six visible cross head screws of the cover and also sensitivity selector knob. Removing the knob requires some kind of friction tool (thumb!) to open the flat head screw in the middle."
    I used an old trick I learned from a watchmaker. To take the screw-down back from a Rolex watch, you're supposed to use a specific Rolex tool whose serrations fit perfectly into the knurled surround of the watch back. However, some of these watches are eighty years old now, and the backs have seen some wear and often some damage. So the tool no longer fits true. Solution? A little rubber ball. I used one of these "power balls", the type that bounce high in the air, to shift the flat head screw. It worked perfectly – and incidently it does the same job on the film-advance lever on my Leica too.
     
  6. could also make two holes in the top to make it easier to open using those needle nose deviders or pliers
     
  7. Hello,
    I just obtained two GX680 film backs but the batteries are dead. I understand you need to remove the back cover to access the batteries. Matti and Martyn say that you first have to remove the ISO selector knob: I see a flat round thing in the middle of the knob, is this what I have to remove? I assume it is a threaded cover which needs to be unscrewd to access the screw underneath. I have tried my thumb with no success, I'll try the "power ball" next, but is there something else I am not understanding right?
    Thanks in advance for any help,
    Mario
     
    terrymc likes this.
  8. necessary to make an incision for a flathead screwdriver. then you can do everything with that screw. you can also polish the screw head after that
     
  9. John Impeller: "necessary to make an incision for a flathead screwdriver"
    On the contrary, NOT necessary. That is just vandalism that will damage the camera. A soft, sticky ball will do the trick – try a squash ball.
     
  10. Hi Martyn, I have tried WD-40, and the soft rubber ball trick, and taking it to a jeweler to use his specialized pliers and tweezers and rubber ball. Any other suggestions before taking a Dremel tool to the screwhead?
     
  11. Is it left-hand thread by any chance?

    I've used double-sided tape on a lollipop stick as a friction wrench. It saves having to push down hard and twist at the same time.
     
  12. Thanks. Just tried what you said. In both directions. No go. Either I'm doing something incredibly stupid, or somebody really did on number on this back.
     
  13. The threads might have been deliberately gummed with Loktite or similar thread adhesive.

    This can usually be released using heat (soldering iron applied to part) or a solvent (acetone - nail varnish remover). However you'll have to be careful if there's any plastic in the vicinity. Both heat and acetone will damage plastic.
     
  14. My friends at Nippon Photoclinic in NYC finally got the screw loose using strong hands and what looked like a piece of bicycle innertube.
     

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