8mm Forum: ST-1200 Drive Rolls

This is topic ST-1200 Drive Rolls in forum 8mm Forum at 8mm Forum.

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Posted by Lawrence Alan Fabbri (Member # 370) on April 04, 2005, 08:45 PM:

Glad to back on the Forum and thanks Kevin for the help registering. I have an Elmo ST-1200 that would not go forward or in reverse most of the time. After removing the back cover it seems that a spring was missing that pulled the drive wheels against the shutter blade. I carefully examined the projector for the spring. It does not seem like there ever was a spring there, no witness marks or scratches. I installed a spring that I had and it seems to work fine. I have not run it except to test it and was wondering if I am on the right track. The spring does not have much tension and it seems to work pretty good. If it does require a spring is there somewhere I can get the right one. The Elmo is in near new shape with hardly any wear on the rubber drive rolls and the belts look almost new. I am thinking be that the unit has seen little use because of this missing spring. Thanks Larry

Posted by Jan Bister (Member # 332) on April 04, 2005, 11:11 PM:

Hi Lawrence - we haven't met before but, well, glad to have you back [Big Grin]

Just wondering, were you having the same problem in both the 18fps and 24fps positions, and is your (temporary) solution affecting both speeds in the same manner as well? I don't really have the whole assembly before my mind's eye right now but I have a feeling there's a connection there...

Posted by Lawrence Alan Fabbri (Member # 370) on April 05, 2005, 07:57 PM:

Hi Jan
The spring is pulling the drive wheel assembly towards the shutter wheel. It is the assembly that has the 18 and 24 drive rolls on it that is changed with the lever that is on the back. I hope my description helps. Thanks Larry

Posted by Jan Bister (Member # 332) on April 05, 2005, 10:01 PM:

That's right! I knew there were two rubber rollers but forgot each one was for a different speed plus they can reverse direction (along with the motor). For some reason I was thinking of the way Bell & Howell designed their assemblies: there are two rollers as well but they only go one way (the motor does not reverse) and one roller pushes against the outside of the shutter wheel rim making it go forward whereas the other roller pushes against the inside of the rim making the shutter wheel go in reverse.

Oops. [Cool]

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