8mm Forum: Sankyo projector film-engage problem

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Topic: Sankyo projector film-engage problem

Knut Nordahl
Expert Film Handler

Posts: 173
From: Norway
Registered: Dec 2005

posted February 24, 2006 02:01 AM

I have this little Sankyo Dualux 1000 that I use in my telecine set up. It takes no bigger than 120 m reels, but that is ok. It works almost fine but towards the end of a reel the take-up reel stops, but the feed reel keeps going. What can be the cause of this? It looks clean and ok Inside.

Also if someone can help with this: To thread the film you need to push down on a lever on top of film gate, above the lens. This lever locks and the film is pulled into the machine. When you turn to “lights” on the main switch the lever pops up again.
Is it the same for reverse projecting? OR is the lever supposed to be in locked position when doing reverse projection?
My projector does a nice r-r-r-r-r-r-r-r-r in foreword position both with the lever locked and unlocked, but when it comes to reverse projection the claw will only engage when the lever is held down, but I am not able to lock it, so I do not understand how it is supposed to be.

Regards, Knut

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Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

posted March 07, 2006 11:42 PM

Hi Knut,

(wondering why nobody has answered this one yet)

in regard to the take-up reel stopping, it could be a slipping belt or one that's very stretched and only provides very weak tension. (Another possibility is a worn friction drive or one that's maladjusted.) Try running the projector without film, stop the take-up reel with your hand and see how much resistance you feel and how fast it spins up to speed again once you let go of it... that will give you a good indication of the problem.

The lever you mention is only for threading (loading) film prior to projecting it - like you said, you lock it down to load the film, then it's "lights on" once the take-up reel catches the film and the lever pops up and you're watching the film. [Smile]

It stays up otherwise, including during reverse projection. However if you find that the picture is jumping and/or you hear an unusually loud chattering noise, then momentarily pressing the lever down should restore the film loops and return you to a steady image. That's all [Smile]

You do mention, though, that "the claw will not engage" while projecting in reverse, unless you hold the lever down (which you're not supposed to). Can you elaborate on what you mean by that?

--------------------
Call me Phoenix. *dusts off the ashes*

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Knut Nordahl
Expert Film Handler

Posts: 173
From: Norway
Registered: Dec 2005

posted March 08, 2006 04:02 AM

Hi Jan,

I have had some luck trying to figure out what is wrong with it.
The pin that holds the cover in place also serves as the screw that holds the film thread lever in place.
I accidentally turned this screw to hard with the result that the lever would not pop up when you turned to “lights” on the main switch. Also In reverse it would not pop up, and the projector ran smooth in reverse. When I forced the lever up again, the reverse projection started to act up again. Therefore I tried to adjust the framer button and this helped. The projector was smooth in reverse.

Now the lever will stick because of the screw I screwed in to hard, and I have to manually open it again, both in reverse and forward projection, but it seems to function.

I don’t know what the conclusion is but it seems to be sort of ok.

About the take-up.
It is easy to stop, and starts again fairly quick. I have changed one belt inside the projector. What is the friction drive and how would I go about to check that?

Thanks for your reply.

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Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

posted March 09, 2006 11:35 PM

That belt change might have done the trick... but why not try the "stop-the-reel-by-hand" test again with a FULL reel on the take-up side of the projector, rather than an empty one. See what it does then. [Smile]

Friction drives come in different sizes and shapes... generally they consist of two adjacent cogs with a cork disc (or similar) sandwiched between them, and a spring holding everything together, with some means of adjusting the spring tension. This is what allows the take-up reel to run only as fast as the film feeding onto it allows it to, and to provide a certain degree of tension in order to wind up the film without any slack. You will notice that when the reel is running free without taking up any film, it generally spins a lot faster, i.e. at the actual speed of the mechanism driving the reel spindle - but the friction drive allows the reel to slow down as needed (without the motor having to slow down, too). Hope that explains it somewhat. [Smile]

--------------------
Call me Phoenix. *dusts off the ashes*

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Knut Nordahl
Expert Film Handler

Posts: 173
From: Norway
Registered: Dec 2005

posted March 11, 2006 09:39 AM

Strange...
Just put 400 ft through it, and it seems fine. The take up reel didn't quit. True, I have splurted some wd40 on some shafts, but it didn't seem to help any until now.

I tried to stop the take up reel, and it starts again without any trouble, so I guess it is sort of ok now. Could not find anything that looks like a friction drive. What drives the take up is one of those long metal bands which is more or less in contact with the sprocket wheels inside the projector. Anyway, it seems that this has turned out ok, Jan so thanks for you help.

Knut.

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