8mm Forum: GS1200 Lower Loop

This is topic GS1200 Lower Loop in forum 8mm Forum at 8mm Forum.

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Posted by Paul Adsett (Member # 25) on June 03, 2013, 09:03 AM:

Can someone explain to me how the GS1200 sets the lower loop size right after the threading guides are retracted? I can see how the machine intially threads itself when the auto thread guides are set into place, but exactly what happens once the guides are sprung out by the solenoids? What exactly goes on to set the size of that lower loop, and is there any way to adjust it to get,say, a larger or smaller lower loop? The Eumigs, and other projectors, have totally enclosed threading guides which "lock in" the size of that lower loop, but the Elmo has nothing between the bottom of the gate and the sound head to fix that lower loop. What goes on here?

Posted by Maurizio Di Cintio (Member # 144) on June 03, 2013, 11:10 AM:

The extra, smaller pinch roller (the one placed right before the sound heads) takes care of this task: it's lifted during auto thread, but as soon as the machine is switched to FWD projection, the roller is lowered (along with the mag pressers or even without them if opt playback is required). This causes the lower loop to get its correct shape (facing both inwards and outwards, depending on machine series). As for what you mentioned in another topic, I don't think this might account for the problem you are experiencing with OPT playback...
Hope this helps.

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