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Author Topic: Pay-out or brain wrap fail-safe Tim Asten Film Handler Posts: 98 From: Brighton, United Kingdom Registered: Nov 2006 posted 07-17-2008 06:24 AM                     Our Kinoton ST200 platters have a simple trip roller just above the top deck which, like the Cinemeccanica, stops the projector. However due to the inverter controlled slow ramp down speed of the projector(Kinoton fp40)the film can pull tight and cause damage. I would say though that most brain wraps are caused by operator error. Tim  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 07-17-2008 10:33 AM                        If you are handy with simple electrical curcuits, and simple mechanical engineering then this is something you could easily build yourself. Simply you just need a normally closed switch to interrupt power to the platter when the film tension causes a roller to be pulled up thereby opening the switch and killing the power to the platter.  |  IP: Logged Michael Hossen Expert Film Handler Posts: 136 From: Perth, Australia Registered: Apr 2007 posted 07-17-2008 11:31 AM                        Tim, I agree with you. The 1 time I can remember having a brain wrap happen the film did get a little damages by the sprockets. The wrap was caused by a large glob if sticky stuff that wasn't found by who ever made the print up...  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 07-21-2008 02:16 PM                     The usual wiring for these shuts off the platter power meaning the takeup platter stops and the film goes slack out of the projector. If you have automation with a failsafe switch this stops the show. If you run the projector manually - not entirely rare at a drive-in - the wrap detector doesn't help at all wired this way. Wiring it so the projector motor stops is good as long as there's a fire shutter and someone will get to the system before the fire shutter melts (drive-ins tend to have powerful lamps). The wrap problem turned serious when polyester base film became standard. The old acetate film would just break, polyester is quite strong and I've seen stripped projector gears and platters actually tipped over from brain wraps.  |  IP: Logged Justin Hamaker Film God Posts: 2253 From: Lakeport, CA USA Registered: Jan 2004 posted 07-21-2008 04:26 PM                        In all three theatres where I've worked, the brain wrapped fail safes were wired so they shut down the projector. This is the case on Xetron and Christie lamp houses with Simplex 1050, Simplex Millenium, and Century projectors.. After I started this thread, I asked my boss about this and he said it was a conscious decision because he and the techs felt it added an extra couple seconds of protection against damage from brain wraps. I'm not sure exactly how it's wired, but I'm guessing it's exactly the same as the take-up side fail safe. When the fail safe is tripped, it immediately stops the projector, closes the change-over shutter, kills the lamp, and sounds an alarm. Some times I think these might work just a little too well. My print of Dark Knight had a small amount of adhesive near a lab glue splice which I did not catch on build up. This caused the film to stick just enough that it tripped the fail safe, but by the time I got up stairs it had gone through and everything looked normal. Unfortunately this happened during our Thursday night midnight movie because we didn't get the print in time to do a dry run.  |  IP: Logged Charles Greenlee Jedi Master Film Handler Posts: 801 From: Savannah, Ga, U.S. Registered: Jun 2006 posted 07-21-2008 11:55 PM                        Our wrap detectors were wired in a similar fasion to the failsafe. The effect was the same as a dropped film anyhow. Cuts off both the projector, and platter, and sets off an alarm on the status panel. That's not including the alarm on the wrap detector itself. Since I don't work there anymore, I forget the name. But I'm picturing a blie box, with white screen printing on it, and stars. Mounts on the penthouse of the projector. I'm pretty sure sure it just wires into the same place (automation) as the cut out switch on the failsafe.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 07-22-2008 06:42 AM                        Is there any reason not to just wire the detector in series with the existing failsafe? Seems that would be much better than having it shut off the platter and letting the projector dump film on the floor. For theatres with no automation, a small contactor could be wired to disconnect power from the projector, break the lamphouse remote line, and maybe even mute the sound reader. That would be pretty easy for most to set up, and a lot less expensive than dealing with the damage a serious wrap could cause.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 07-22-2008 09:18 AM                     We wire our wrap detectors in serries with the film presence contact on the TA10 This guarentees quick positive shutdown  |  IP: Logged Eric Burrel Film Handler Posts: 10 From: Chicago, IL, USA Registered: Jul 2008 posted 07-22-2008 06:29 PM                     Our platters were wired directly into the automation to shut down the projectors. It was also nice that we had the lovely Neumade annunciator that announced any projector alarms over the radios right away. Someone did make the mistake of leaving the manual motor switch on one time and had a brain wrap. We had Kinoton PK60s. As gentle as they are normally with the film, if film gets caught in them, they will eat it up.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 07-23-2008 06:05 AM                        quote: Gordon McLeod We wire our wrap detectors in serries with the film presence contact on the TA10 This guarentees quick positive shutdown Exactly as I do mine.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 07-24-2008 10:26 AM                        Whatever way it is done I think it is important that it cut power to the platter system. If you have a "Stuck" pay out actuator causing the payout platter to spin at full speed and "reverse wrap" just shutting down the projector will not prevent the wrap from getting worse.  |  IP: Logged Eric Burrel Film Handler Posts: 10 From: Chicago, IL, USA Registered: Jul 2008 posted 07-24-2008 08:49 PM                     All discussion aside, I think most of us can safely agree that something in this regard is better than nothing...sadly, i am working with the nothing end of this..  |  IP: Logged

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