Film-Tech Forum ARCHIVE: Changeover Problems

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Posted by Zack Strickland (Member # 5503) on 03-07-2010, 08:43 PM:

Last one for today!!!
We have strong changeovers and about half of them in the booth are rubber banded in the up position because they "don't work" any more. We use the orange douser handles on the projectors to manually start the show. (we have platters) Anyone know why the changeovers go out? are they crappy? easy fix? thanks

here's some pics:

another:

Posted by Chris Slycord (Member # 4239) on 03-07-2010, 08:59 PM:

Based on the number of posts you've made recently on stuff like this, do you have a technician?

And actually, with platters there's no real reason to need a changeover. You could have a cue that strikes the lamp (or change the normal dowser open cue to strike it) and have your intermission cue kill it.

Posted by Mark Gulbrandsen (Member # 72) on 03-07-2010, 09:48 PM:

The basic idea is good, the implementation is lousy! You may find a blown fuse in the automation, coils that are burnt out, springs that ride along the rod on top that are too tight... or they may have just plain fallen apart... I've seen all of these happen on these change overs. IN the lower photo you are missing the small pin that goes through the hole. They break constantly and should have been made from hardened steel. The parts are cheap and some can be had from a decent size hardware store. If you don't have technical abilities then you should call in a qualified technician!!

Mark

Posted by Monte L Fullmer (Member # 2797) on 03-07-2010, 11:58 PM:

Ya, there is a common pin inbetween the two "push/pull" selenoids that loves to bust-a major weak link in the system (definitely a "piss-poor typical STRONG contraption"). I'll snitch a pin from the front to replace, then make a paper clip (or, even a piece of 18g solid wire) replacement pin where I did the snitch.

Also, if you want smoother douser openings, take the top off and right where the spring clips that run against the square shaft that holds the douser open or close, rub some petroleum jelly on that square shaft in that area. Makes that assembly open and close so much smoother.

-Monte

Posted by Joe Redifer (Member # 3) on 03-08-2010, 12:19 AM:

Chris has a good solution, but I am betting that this booth requires multiple strikes of the xenon bulb before it stays lit. Still, keeping the hand dowser closed is acceptable. After all, the xenon doesn't need to turn off multiple times at the end. A simple wire move (C.O. CLOSE) would enable the operation just fine and the audience wouldn't see the multiple strikes nor the tailing out. Don't switch the xenon on and the C.O. OPEN wires.

Posted by Louis Bornwasser (Member # 3063) on 03-08-2010, 03:48 PM:

Copy of a really good Kelmar changeover. No trouble with the Kelmar. Echoing Monte; pins are very poor. Order the pins from Kelmar and you will never break another pin. I have "repinned" entire complexes.

I am assuming that you are electrically OK. Louis

Posted by Scott Norwood (Member # 30) on 03-08-2010, 05:53 PM:

Joe--the c/o open/close should be a pulse, while the xenon automation control should be a held contact closure. You would need to do more than swap the wires to make this change (adding a latching relay would do it).

(I'm assuming a typical American-made projector/lamphouse here.)

Posted by Monte L Fullmer (Member # 2797) on 03-08-2010, 09:03 PM:

? What happens when you're getting a bulb that has begun to dbl or hard strike and you got a douser open?

And he's got STRONG consoles where these things are prone for dbl and hard strikes - not like Christie consoles with a lot better rectifer where dbl an hard strikes are rare.

I think that would to start to look pretty tacky.

I'd be getting that douser repaired..

-Monte

Posted by Joe Redifer (Member # 3) on 03-08-2010, 09:39 PM:

Scott, yes, but he only needs to turn off the bulb, not turn it on with the C.O. pulse. But still, you're right. There is no reason to do this in lieu of a changeover unless you have a lengthy piece of full coat mag or other black leader so the bulb has time to stabilize.

Posted by Joe Redifer (Member # 3) on 03-12-2010, 05:17 AM:

OK can anyone tell me what the difference is between this changeover and the Kelmar changeover? I have 4 of these Strongs and a Kelmar. They seem pretty much identical to me, inside and out. I had an issue with a Strong one Thursday night. The management was complaining that it either did not always open or close all of the way. The problem turned out to be the douser plate had warped to the point to where it was rubbing against the silver frame in front of it. Easy fix. The changeover itself is fine.

As for Zack's problem, it sounds like the the springs inside are too loose and it falls back down during the show due to vibration... at least that's what the rubber band leads me to believe. There isn't enough tension to keep the plate up without it. I wouldn't go poking around inside one of these things unless you know what you are doing, but the springs (they have a slight "L" shape) can be removed, bent back in the direction of the post and reattached. Just don't overdo it. But it would be best to replace the springs altogether with new ones. They are cheap, but I think Strong has a minimum $25 order or something like that. You have to remove the changeover from the projector to have decent access to the 4 screws to remove the top cover. The springs are held on with two screws each.

Posted by Louis Bornwasser (Member # 3063) on 03-12-2010, 09:04 AM:

The 2 companies make (almost) identical changeovers. The main deficiency of the Strong is workmanship, finish, and especilly the frail clevis pins mounted internally.

I have only a few Strong changeovers around; all of which now have Kelmar clevis pins in them. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 03-12-2010, 11:46 AM:

Louis is right Joe. The strong knockoffs are passable when used with a platter system but I'd never use them in a changeover house.

Even worse is the totally piece of [bs]

CFS/Rentec knockoffs. Wimpy coils prone to burnout (the Kelmars rarely do), weak springs which break, hardware that loosens or breaks, total CRAP!! They do make nice paperweights or are useful to throw at stupid people though. [Big Grin]