Contax G1 Screw Drive Focusing Problems

Discussion in '35mm Cameras and Accessories' started by MAubrey, Feb 16, 2016.

  1. MAubrey

    MAubrey Member

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    All of the sudden my G1 has started misbehaving. When I focus, the viewfinder adjusts the parallax, but nothing happens on the lens. The screw drive either isn't moving or for some reasons isn't catching the lens screw.

    Advice? Suggestions?
     
  2. OP
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    MAubrey

    MAubrey Member

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    Well, follow up (despite the lack of response):

    It seems the problem is that one of the pins in the camera mount is stuck in a pushed down position and isn't coming in contact with the lens. I think I can fix this...I hope.
     
  3. tuanco1080

    tuanco1080 Member

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    Hi Aubrey, have you fix your contax G1, my G1 has similar problem. So sad
     
  4. OP
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    MAubrey

    MAubrey Member

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    Hi Tuanco,

    I had given up on the problem for a bit and let the camera sit. But a few weeks ago I bought a G1 repair manual on Ebay. I was able to disassemble things enough to get to the pin problem and I found that the pin was stuck because it had gotten bent. I'd go out a limb and guess if you had a stuck pin, too, then that's the problem. I'm not sure I can bend mine back. So I'm debating what I'll do. I have a second non-green label G1 that I could salvage a pin from, but making a still working camera into a parts camera doesn't seem right...
     
    Last edited: Jan 27, 2018
  5. neilt3

    neilt3 Member

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    Is the pin not something that a clock repairer could make for you , if you have one local to show the part too ?
     
  6. OP
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    MAubrey

    MAubrey Member

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    Interesting idea. I don't know what's available in my area, but if that's true, it would be worth checking out.
     
  7. neilt3

    neilt3 Member

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    The specialists that repair/restore old clocks and watches , 100+ year old types etc , can't buy replacement parts so have to turn spindles and the likes down on small lathes .
    They have to cut out their own new cogs and so on if needed too .
    The part your after would be fairly simple for them to do , or a modelmaker hobbyist if you know any .

    Might be worth making a few phonecalls , then follow up by sending some photo's with a ruler next to it to give a sense of scale .
    It shouldn't be too hard to find someone willing and able to help .

    You could start a thread in the Camera building , repair forum ;
    https://www.photrio.com/forum/forums/camera-building-repairs-modification.77/
    State what part of the world your in and ask if anyone can recomend someone to make /supply this part .
    You might even get a lead on getting a genuine replacement part .

    Good luck in your search .

    Regards , Neil .
     
  8. shutterfinger

    shutterfinger Subscriber

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    Heating it then immediately reforming it in the flat section of a pair of needle nose pliers should straighten it out. A 40 watt soldering iron should get it warm enough quickly to straighten.
    I assume the pin is 1/8 inch diameter or less.
     
  9. tuanco1080

    tuanco1080 Member

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    Special thanks for reply. I am thinking to repair, to bend the pin by my self. Can you show me how to disassemble the pin. Thanks
     
  10. OP
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    MAubrey

    MAubrey Member

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    This is do-at-your-own-risk procedure. I'm not responsible for anything...these pins are tiny and the springs are hard to get back in place, but here's what I did:
    1. Remove the bottom plate of the camera.
    2. There's a ribbon that goes across the center of the bottom the short way across that makes a T on the rear side. That ribbon connects the mount's contacts to the rest of the camera electronics.
    3. There are two screws on each end of the T to remove. You'll need to make sure you don't loose those pieces. There'll be a rubber bit, a couple gold rings, and the screws--note the order for reassembly.
    4. There are two black screws inside the mount with the pins in the middle that need to be removed.
    5. With the ribbon loose on the other end, you can pull the block with the pins out partially.
    6. On the backside of that block with the pins, you'll find two more screws connecting the ribbon to the pins. Held in place with a metal plate.
    7. Note the order of the layers before you remove the screws.
    8. Have a open surface that's bounded ready (I used a white 8x10 developing tray).
    9. When you unscrew those two screws and separate the ribbon, the pins are spring loaded against the ribbon and they'll fly out when the pressure on them is gone.
    10. Put the five tiny springs and five pins in some place safe.
    11. [fix or replace your bad pin]
    12. If you are successful getting the pin fixed, putting the pins back is much more difficult.
    13. I put the pins and springs into their holds again and put a piece of paper against them and tapped it around to the other side of the pin block in order to keep the springs in the tense position.
    14. Then screwed the ribbon & plate in place, but did not tighten the screws .
    15. I slid the paper out from between the ribbons and the pins and tightened the screws.
    16. Reasssemble everything else in reverse
    The "easier way" would be to buy the repair manual on Ebay and do a complete disassembly so that the ribbon is completely separated from the camera. That would make putting the pins back significantly easier, since you won't having to do it inside the mount. That would, of course, involve far more complication in the rest of the disassembly. The repair manual is on Ebay, if you want the reference or to go that route: https://www.ebay.com/itm/Contax-G1-Camera-Service-Repair-Manual/192438622109

    I can happily say, however, that I have a fully functional camera again.
     
    Last edited: Mar 5, 2018
  11. ozmoose

    ozmoose Member

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    For what this information is worth, I had this exact same problem with my G1 in 2006. A repairman in Melbourne, Australia (supposedly factory trained by Contax) repaired the pins for me. It cost me A$160.

    When I retrieved the (functioning) camera and questioned the (at the time) high cost, I was told all the pins had to be taken out and straightened, the entire pin area cleaned, and the pins reassembled.

    The G1 is still used regularly and it has worked perfectly ever since.

    The repair sequence by MAubrey (#10) may work for you, but I for one would never dare to try to do this...
     
  12. tuanco1080

    tuanco1080 Member

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    @MAubrey thanks for your sharing. Congrat your G1 fully function. I will try
     
  13. OP
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    MAubrey

    MAubrey Member

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    Yes, it's a difficult, tedious, precise, and high risk procedure. And as I said, very much a do-at-your-own-risk affair.
     
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