Film-Tech Forum ARCHIVE: Changeover douser "drifting"

This is topic Changeover douser "drifting" in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by David E. Nedrow (Member # 4981) on 03-23-2011, 06:40 PM:

(Had been firewall shutter post, but figured out my mis-observation)

I just swapped XL heads and I'm having a problem where, after a relatively short period of time, say 1-2 minutes, the changeover douser starts to drift closed on what had been #2 (but is now #1). This projector had run without problem as recently as October.

What needs tightened? [Wink]

-David

Posted by Joe Redifer (Member # 3) on 03-23-2011, 07:24 PM:

I'm not overly familiar with fire shutters, but can you remove it? Chances are pretty slim that you'll be running any nitrate any time soon, so it's not needed.

Are you, by chance, talking about the electric douser/changeover?

Posted by David E. Nedrow (Member # 4981) on 03-23-2011, 07:38 PM:

Joe,

You're right. I didn't take the time to actually observe what was happening, beyond seeing what was happening on the screen. /me must be beaten.

It is the Simplex changeover that is drifting closed, which also explains why the fire shutter re-set button didn't work, which should have been my first clue it wasn't the fire shutter. D'oh!

-David

Posted by Scott Norwood (Member # 30) on 03-23-2011, 07:47 PM:

Are these Zipper changeovers, Kelmar changeovers, or something else?

On the Zipper, you may need to tighten the screw on the top (there should be a little ball in there, too; perhaps it slipped out when you moved the machine).

Posted by Randy Stankey (Member # 64) on 03-23-2011, 08:15 PM:

There's a little leaf spring in the Kelmar changeovers that often breaks or gets lose. If it does, the solenoid rod will gradually slip closed during the presentation.

Happens a lot.

Posted by Louis Bornwasser (Member # 3063) on 03-23-2011, 09:23 PM:

This has to be a Simplex/Zipper changeover. Just buy a Kelmar. Not worth fixing. No comparison. Louis

Posted by Joe Redifer (Member # 3) on 03-23-2011, 10:09 PM:

Yeah I had trouble with the zippers creeping back down during the show, not opening all of the way, requiring an insanely long pulse to open, etc. I couldn't get the thing to work properly for the life of me. Fortunately we had a couple of Kelmar changeovers which were brand new just laying around for reasons unbeknownst so me so I installed one. It required a bit of modification to the rod as it needed to be bent a little to avoid the shutter, but after that it worked great forever.

Since we had two new Kelmar changeovers, I'm pretty sure the other one is still there in the abandoned theater which has not been demolished yet. I didn't even think of it when we were taking everything out of the theater and it wasn't in an obvious place. Now it's just sitting there, never having been used, never will be used. Its dreams of the future are shattered, forever lonely. Oh well.

Posted by David E. Nedrow (Member # 4981) on 03-24-2011, 07:39 PM:

Yeah, now I've got two Simplex electric changeovers that don't quite work. [Wink]

The Kelmar replacement isn't terribly expensive, even at list.

Time to start saving pennies. Until then, tape to the rescue! [Wink]

-David

Posted by Joe Redifer (Member # 3) on 03-24-2011, 07:50 PM:

Are you running reel to reel? If not, I'd just remove them completely and use the had douser if need be. If you are running reel to reel, then yeah, tape for now I suppose.

Posted by John Wilson (Member # 269) on 03-24-2011, 08:03 PM:

quote: Joe Redifer
Yeah I had trouble with the zippers creeping back down during the show, not opening all of the way, requiring an insanely long pulse to open, etc. I couldn't get the thing to work properly for the life of me.

That sounds naughty...! [evil]

I had written a response when this was first posted and recommended then to make sure the screw was tightened on the cable but then before I posted it I re-read it and saw it had mentioned the fire shutter so I deleted it and moved on.

Sometimes (assuming it's a 'Zipper' brand) the mechanism can be forced manually and affect the cable by bending it so it doesn't have a straight friction-free run thus not getting full up/down action happening.

Are you sure it's OK from the start and that it gets worse during the show or could it be that it's not opening up properly in the first place? If it is indeed drifting closed, make a mark on the cable where the shutter is attached and make a mark to see where the cable is to start with. If the cable is found to be moving, then the solenoid is not holding on.