8mm Forum: Help, Elmo ST-600 Slipping take up spool

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Posted by Stig Lundberg 2 (Member # 2999) on January 15, 2014, 05:30 PM:

Projector Elmo St-600: The connection to the spool arms goes via a spring loaded sliding mechanism, that seems to be too weak as the take up spool stops when the spool takes up film and becomes heavier. There is not enough friction between the belt driven plastic wheel and some kind of fabric plate. Spring tension is set with a bolt that is glued. (Usually means don't touch this)Ideas about the best way to adjust friction? Dissolve the glue and tighten the screw, or should the fabric plate be replaced?

Posted by John Capazzo (Member # 157) on January 15, 2014, 06:03 PM:

Sounds like the belts is too large. There is no adjustment on ST 600 to tighten the resistance. Also, the upper belt should be above the middle pulley. I can send you a pic what it should look like if you reply with your email.

John

Posted by John Hermes (Member # 1367) on January 15, 2014, 06:08 PM:

From time to time, I disassemble the take-up clutch and clean the parts, also relubing afterwards. The "glue" is a Locktite-type thing. I've found it's not really necessary, the screw will hold on its own. Turning the spring mechanism clockwise (part 6) in service manual figure 34 will increase take-up torque. Make sure you have a good take-up belt, too, as that is part of the equation. According to the ST-600 service manual (page 50), the take-up tension should be between 25-35 grams.

[ January 15, 2014, 07:13 PM: Message edited by: John Hermes ]

Posted by Stig Lundberg 2 (Member # 2999) on January 16, 2014, 04:09 PM:

Thanks John and John, the drive belts were just renewed and I've noticed the large one had to go over the middle roller as you wrote. The take up belt on front arm is none elastic and seems fine, but the problem is the rear arm which has no belt, but a line of cogwheels. I don't have the service manual (also wanted by another member Dave Alligan in another topic 2007). Could you please email me a copy of that page and figure John? The ends of the spring is stuck into holes in plates on each side so I don't figure how to twist it.

Posted by John Hermes (Member # 1367) on January 16, 2014, 07:30 PM:

Stig, just loosen the nut on the end of the shaft and then, using an open end wrench of the right size, turn the front plate a turn or so clockwise. This will increase spring tension and take-up torque. Snug up the end nut and test the torque with a take-up reel. If need be, adjust the plate again for the right torque, then tighten the nut against the plate as the final step. Unless you have a spring guage to test the torque tension, it's a trial and error thing. There is leeway of ten grams of torque so it doesn't have to be super accurate.

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