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  • GS-1200 right side line/scratch

    After modification of the upper guides and replacing the lower tensioner with a roller I was still seeing a far right line close to the edge of the frame after initial run. Research of the Archive mentions the sound presser pins.
    The two at the rear that contact the main stripe also contact the printed image area. These pins or feet are polished hard plastic but can trap small dust or dirt particles and hold them there during projection causing the infamous Elmo right frame scratch. These pins were initially a different and better design in earlier GS versions but the problem can be easily resolved. You remove the sound presser roller part first, then the sound presser. The black square thing with four feet. The two that are at the back need to be filed to half the footprint with decent files. Screen your test print until the coast is clear.
    it has eliminated all film impressions.
    hope this helps GS-1200 owners.

  • #2
    Not a great design, a fixed pin with film passing over it at speed ?, i looked at changing mine for new one's, but when i saw what they were made of i thought it would have been a short term fix. If a small slot could be put in the pin, then perhaps a small thin wheel could be fitted to it, which would rotate but still make contact with the film because of the spring loading, perhaps change the pins to brass for easier machining, try one or two materials for the wheel part, at bit of R/D needed here i guess.........

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    • #3
      I usually clean and polish the 4 presser pins with a Q-tip and furniture polish before every screening, so far so good.

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      • #4
        You have the right idea Paul :-) Before the local cinema projectionist of some age retired bless him he used to keep saying 'clean everything that touches the films before a show'. A time served man and boy how we miss him since Digital came in.
        He got me into the leather tipped sticks instead of cotton buds which seem to cling to the muck rather than dropping it into the works. The leather sticks can also be found at 8mm width if you look hard enough.
        Burton my oldest GS still has original guides in and zero lines. I remove the guides, inspect and re-coat before replacing similar to Paul.

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        • #5
          No amount of polish would have fixed mine, with or without the leather, they were shot completely, big flat grooves on all of them. they are after all only made of a cheap plastic, polythene i would guess, not very tough............

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          • #6
            Excellent point regarding filing the presser pins Burton, I had never thought of that one, so far since I modified my guides I have not seen any problems with any scratching on the screen, but those pins might be something to look into in the future. I do clean the pins and sound head etc after every screening and the films I do have are clean as well, as much as possible without going over the top.

            Anyway this is what I did a few years ago.

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            • #7
              Superb Job Graham! I went the route of eliminating the Guide #2 microswitch. I used epoxy to secure the second roller screw which didn't alow enough room to re-install. I have 2 GS machines, both Mark 3. I modified the upper guides in both as soon as extra Elmo rollers were provided by a good Forum member friend.
              After doing so I ran test prints through both machines and still had right side lines with projector number 1, which is my dedicated recording machine. No lines on projector 2.
              I used diamond fIles to remove the portion or the main track pins that contact the emulsion side printed image. As I did so I would periodically put everything back together and run through a test loop. The line was moving further to the right. A few more stokes of the file then the test loop ran clear after 10 minutes continuous projection. The point here is my number 2 machine has not scratched a single film, so You, Paul and many others are doing the right thing. But this test proved that the presser pins can lead to lines at best, scratches at worst.

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              • #8
                Some very good ideas for GS owners here, you do get a bit paranoid with cleaning and maintenance so your prints are damage free, the important thing is dont take it for granted that your machine is not going to mark at some point, any pre film checks are a start, I had a tip I use on a regular basis and that's run some clear leader through the machine, Mark

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                • #9
                  Thanks Burton

                  The advice on those pins is something I will certainly keep an eye on. I somethings think it would have been a good idea if Elmo had made a manual threading GS1200 as well, to get rid of those guides and keep it simple. My old ST1200 has a rubber roller, that gently presses the film onto the sound head, that kind of thing would have, I think, be better than those four pins rubbing on the film.

                  Even a better gate arrangement would be better, I think we need to build a new scratch free projector from old machines, one using a 16mm lens and aperture plate that can manually open or close "top and bottom" to allow for the full Scope frame image, that is often there on the film, but we can't take advantage of it, due to that aperture plate

                  All food for thought, anyone game to build such a 8mm projector?

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                  • #10
                    I thought about this graham, what about modifying the elmo cl machine for super 8 ?, would be possible i wonder ....

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                    • #11
                      I am sure it is Paul, likewise I was given a ST180 for parts and a Eiki 16mm "blue model". Its all sitting there in the garage. I keep looking at it and think if I could fit the ST180 parts like the soundhead etc into the Eiki as a play back only machine it would be great, even just having a pre-amp with Aux out to a amp. Using a Eiki 38mm or 50mm lens. would be a lot better than any Super 8 zoom.

                      I am sure using a Elmo cl would work also. The thing is, as with the Eiki the motor etc on 16mm is solid stuff. I remember you could buy once upon a time, a converted 16mm for 9.5mm. If that can be done then I cant see any reason that a 16mm could not be converted to Super8 .

                      Just got to put on that thinking cap, anything is possible

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                      • #12
                        Click image for larger version

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                        • #13
                          The 9.5 conversion was by "Buckingham Film Services"
                          9.5 is nearer to 16 mm dimensions ,so maybe a simpler conversion than to super 8.

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                          • #14
                            Unless you are running a 'Cineavision' formatted print, super 8 (1.36:1) and 16mm (1.34:1) won't give you the full scope image because on 35mm it requires a 1.17∶1 frame. The top and bottom are cropped on reduction to S8/ 16mm.

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