8mm Forum: ELMO SP Hi-Deluxe synchtonization

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Topic: ELMO SP Hi-Deluxe synchtonization

Bernd Ackermann
Junior
Posts: 3
From: Berlin, Germany
Registered: Nov 2007

posted November 27, 2007 11:03 AM

Hello everybody,

I am trying to synchronize my projector with my camcorder by feeding frame pulses from the camcorder to the synchronization input of the projector (pins 4, 5).
I am using every third frame pulse in order to achieve a 16.67 Hz pulse train.
The pulses have 3 ms length and 60 mA height.
Sometimes it works (preferably when there is no film in the projector), but most of the times the projector would run too slow and with oscillating speed.
I wonder if this is a fault of the projector or if my pulses have the wrong shape.

Does anybody know the correct specification of the synchronization input?
Also any hint would be helpful.

Thanks,
Bernd

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Mike Peckham
Phenomenal Film Handler

Posts: 1461
From: West Sussex, UK.
Registered: Jun 2003

posted November 27, 2007 11:52 AM

Hi Bernd

Welcome to the forum!

Not sure of the exact technical specification you might be looking for but I can tell you that I have used my Elmo SP Hi-Deluxe synchronised with one of Pedros boxes, these I think are designed primarily for the GS 1200. The spec for the SP therefore is probably similar to that of the GS so if anyone can offer that...

However, I had mixed success. It was necessary to thoroughly overhaul the projector before it was possible to get it to synchronise and then remain in synch, in addition, it had to have a good warm up time too, I would have to leave it running without a film in it for about 10 mins before I could be sure of getting to run smoothly in synch.

Once this was all done though it was possible to synchronise it to 16 and 18fps though it always struggles at 24 - not meant to run that fast I suppose and when it was fed the pulse for 25fps it sometimes had difficulty catching up with itself and the speed oscilated.

Hope that's useful.

Mike [Smile]

--------------------
Auntie Em must have stopped wondering where I am by now...

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Bernd Ackermann
Junior
Posts: 3
From: Berlin, Germany
Registered: Nov 2007

posted November 28, 2007 10:54 AM

Mike,
that was a speedy reply, and it was useful because it showed me which way to go.

With your experiences in mind I think the pulse shape is not the problem but rather the limited motor power which seems to take the stability of the speed control to its limits. Of course my projector would need to get overauled, too, to reduce friction.

Today I did some tests and I was able to start synchronous runs in cold condition with a film in the projector, but with the take-up reel removed. There seems to be a dynamical problem with accelerating the large reel. The only problem is starting, once it runs synchronously, it will continue. But driving the reel separately is not a practical solution.

Then I found out, that the projector is able to start at synchronous speed after a 10 mins warmup, with the air output of the projector covered with sticky tape so that it gets really warm. It seems that this solves my problem.

Many thanks for your hints,

Bernd

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