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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Kinoton 38E electric douser not fully blocking

   
Author Topic: Kinoton 38E electric douser not fully blocking
Abraham Robinson
Film Handler

Posts: 16
From: Oakland, California, USA
Registered: Oct 2017


 - posted 02-12-2018 04:40 PM      Profile for Abraham Robinson     Send New Private Message       Edit/Delete Post 
I can still see some of the image bleeding through (top-right corner on screen) from Projector-2, after I switch over to #1.

Is this something I can adjust myself?
For now I can lean over, and pull the manual douser asap after the changeover, but with the delay and bleed, it looks pretty amateur...

thanks!!

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12209
From: Annapolis, MD
Registered: Dec 1999


 - posted 02-12-2018 08:54 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
The European changeovers (all of them) are pretty lame and Kinoton is no exception. And think, the one you have is the VAST improvement to what came before it (the lollipop).

You CAN adjust it be you have to be VERY careful. The shutter is always spinning when the power is on and you CAN'T open that cover with the sutter spinning. there is no way to pull the cover off without catching the blade and damaging it.

Odds are, it isn't that the dowser is closing too far so much as the douser is bouncing. When the douser closes, there is a piston that dampens the closing action (accomplished via a spring).

The adjustments you have are:
1) Return spring tension
2) Damper Piston relative to the dowser arm
3) The block that attaches to the dowser pivot shaft in how it hits the damper.

I tend to adjust it with the power off and manually pull the dowser open and then release to see how it behaves. Adjust for best action then power the machine up with the shutter cover off and use the dowser controls to see if any fine-tuning is required. Then do the same on the other machine so they behave as close to identical as possible.

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Abraham Robinson
Film Handler

Posts: 16
From: Oakland, California, USA
Registered: Oct 2017


 - posted 02-13-2018 08:07 PM      Profile for Abraham Robinson     Send New Private Message       Edit/Delete Post 
Thanks Steve!

I was able to open it up today and you are 100% right. The dowser is bouncing back, with its final resting position landing slightly too far back towards the open position.

I wonder if this is also causing the 'ghosting' momentary double-exposure that happens on changeovers, though that appears to be happening on both projectors (while this issue only appears on 1).

We had our service tech come by about a month ago to look at the double-exposure issue (the closed-dowser misalignment wasn't appearing then), and he put some oil in the dowser mechanism, and said to wait a couple weeks to see if that would solve it (it did not).

I'm going to wait until next week to try to make an adjustment, we have a series this weekend and I'm afraid of making it worse. After that we likely won't be running 35mm for a couple months.

Do you have a suggestion for which adjustment to try first? it seems the piston is the most difficult to access.

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Carl Martin
Phenomenal Film Handler

Posts: 1395
From: Oakland, CA, USA
Registered: Feb 2002


 - posted 02-14-2018 03:50 AM      Profile for Carl Martin   Author's Homepage   Email Carl Martin   Send New Private Message       Edit/Delete Post 
abraham, apparently i haven't been posting enough lately to look at your profile, but i'm dying to know what venue you're working at. (i make a point of knowing about all film screenings in the bay area.) my best guess is it's the coppola theater at sf state, as i heard there was a kiarostami event happening this weekend, but of course i can't find any listing online of what actually is screening, or what format. am i warm?

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Sam D. Chavez
Film God

Posts: 2087
From: Martinez, CA USA
Registered: Aug 2003


 - posted 02-14-2018 12:12 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
Maybe MoMa?

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Peter Hall
Master Film Handler

Posts: 307
From: London, UK
Registered: Dec 2000


 - posted 02-14-2018 07:05 PM      Profile for Peter Hall   Author's Homepage   Email Peter Hall   Send New Private Message       Edit/Delete Post 
Hi - there were three types of changeove on the FP20 ;
1. Twin 6VAC coils, one for open and one for shut. These worked and gave a smooth but slow changeover and were prone to siezing as the low voltage coils were gutless
2. The same with 24VAC coils - I thought these were the best as they used the same coils to open and close, giving a quick and even fade
3. The later 24VAC coil to open, with a spring to close and a dashpot to dampen the bounce on close. Great for a single machine install however whatever you to do it, the coil to open will always be quicker than the spring to close, giving a quick "flash" on screen with both shutters open.
I liked the shutter on the DP70 / DP75 - a larger "open" solenoid and a massive return spring.
We had some issues with later FP30s and really short lenses in preview theatres with light leakage and it turned out to be stray light bouncing off the closed shutter - a can of black radiator paint fixed this.
Adam - curious that your tech oiled anything around the gate area - we run these clean and dry. Any oil or grease turns to glue after quick mix of heat and dust..

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Carl Martin
Phenomenal Film Handler

Posts: 1395
From: Oakland, CA, USA
Registered: Feb 2002


 - posted 02-16-2018 04:35 AM      Profile for Carl Martin   Author's Homepage   Email Carl Martin   Send New Private Message       Edit/Delete Post 
ah yes, must be moma, as they used to have simplexes and have kinotons now, and are wrapping up their claire denis series this weekend.

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