8mm Forum: Smoke from Ditmar 2960

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Topic: Smoke from Ditmar 2960

Alexander Lechner
Expert Film Handler

Posts: 118
From: Leoben, Austria
Registered: Apr 2009

posted November 22, 2010 12:13 AM

I recently got this projector from the local photo shop; it looks to be in a very good condition and it does run. With the mechanical (top) part off there is no problem; but once I connect the top part there is smoke developing after some time. I localised the source of the smoke: it's coming from the inside (?!) of the ceramic tube that holds the resistance wire for the speed setting.
The mechanical parts run smoothly, so there is only a bit more load on the motor when it is connected - the resistance wire will therefore heat up a bit more by more current going through it; but what's there to produce smoke? So far I couldn't figure out what the immediate smoke producer actually is.
Anybody with any ideas?

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Alex

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Martin Jones
Phenomenal Film Handler

Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008

posted November 22, 2010 04:04 AM

How long have you run it with smoke being produced?
Remember that an ordinary electric fire which has not been used for some time may produce large quantities of smoke and a terrible smell for some time when used again... simply due to accumulated dust from the atmosphere which might not be visible to the eye.

Smoke does not always mean fire; if the resistance wire itself is not glowing (check in the dark) there is unlikely to be an overload.

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Retired TV Service Engineer
Ongoing interest in Telecine....

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Alexander Lechner
Expert Film Handler

Posts: 118
From: Leoben, Austria
Registered: Apr 2009

posted November 22, 2010 04:24 AM

I only had it running for about a minute with smoke producing. I'd need to go to a better ventilated place to try for a longer time - it also makes you uneasy when you see smoke coming out of the machine.
There is no visible dust, which I found amazing considering that this machine is about 75 years old, but as you say only what I could see with the naked eye. The only thing is spray that seems to be old oil from the gears (?). But again, I can't see any of it on the resistance coils.
I will follow your instructions and try to see whether the resistance wire starts glowing - if not I'll run it for ten minutes and research the outcome.
Thank you for your advice.

--------------------
Alex

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Alexander Lechner
Expert Film Handler

Posts: 118
From: Leoben, Austria
Registered: Apr 2009

posted November 23, 2010 12:25 AM

I let it run without (mechanical) load and after a longer while it also started smoking from the same place. There is no glow of the resistance wires in the dark.
After ten minutes of running there was still some smoke coming from the ceramic tube that holds the wires and I am convinced now that the smoke originates from oil that found its way from the mechanical part to the electric part - it makes sense when you think about the lubrication concept of this machine.

--------------------
Alex

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