Film-Tech Forum ARCHIVE: Pay-out or brain wrap fail-safe

This is topic Pay-out or brain wrap fail-safe in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Justin Hamaker (Member # 2165) on 06-20-2008, 04:59 PM:

Are these fail-safe devices still available? I looked up AVASK Inc and while it comes up with the same address as on the unit, when I called the number, it was for a different company.

I want to find one for our drive-in projector.

If I happen to find one, how difficult are they to install? We have a Christie 4K lamphouse (I don't know the exact model) with a Simplex XL projector.

Posted by Joe Redifer (Member # 3) on 06-20-2008, 05:13 PM:

Lamphouse and projector are irrelevant. What this does is cut power to the platter causing the take-up to fail and the failsafes on the projector to drop. I don't see why you couldn't install Strong's tension-safe device on your "Drive-in" platter (is that seriously the brand name of the thing?) as it is definitely a better design than that thing in your picture, despite my hatred for most things Strong. It mounts at the very top of the unit. There might be some funky wire splicing involved.

Posted by Mike Blakesley (Member # 26) on 06-20-2008, 05:20 PM:

quote: Joe Redifer
on your "Drive-in" platter (is that seriously the brand name of the thing?)

There really was (or maybe is?) a company called "Drive-In Theatre Manufacturing Company" that made platters. Salespeople and techs would abbreviate it "DITMCO" and pronouce it "dit-m'co."

Posted by Joe Redifer (Member # 3) on 06-20-2008, 05:24 PM:

Waitaminute. For some reason when I think "Drive-in" I think "Speco". Any relation?

Posted by Justin Hamaker (Member # 2165) on 06-20-2008, 06:20 PM:

This isn't a brand thing, it's just that I have these fail-safes on the 5 projectors at my indoor and since it's the same brand of platter, I just felt it best to stick with what we know.

Joe, from your post, I don't think you know how these fail-safes work. They replace the bottom roller on the pay-out side of the platter. When the film gets pulled tight - like when you have a brain wrap, they cause the projector to shut down so that it doesn't ruin the film or pull the guidance rollers out of alignment or anything else bad.

Posted by David Zylstra (Member # 4230) on 06-20-2008, 06:53 PM:

I recall a little about this company - they had a niche market to retrofit platters with wrap detectors when polyester film had static issues. The biggest thing I remember is the reps at one ShowEast dressed up in drag as "Poly" and "Ester", another year I think they were the ones with headbands made of film (or was that the company that had a mechanism to cut the film if a wrap was detected?).

I have no clue if they are still in business, but many current wrap detectors should be adaptable to any platter if the geometry is correct. If you have Christie platters they may have a retrofit kit for theirs.

I do recall a unit that cut the platter power, but I don't remember which one it was.

Posted by James Westbrook (Member # 3690) on 06-20-2008, 06:55 PM:

The Drive-In Manufacturing Company changed it's name to SPECO in the 80s. SPECO is supposed to be an acronym, but I forget what it's supposed to mean.

Posted by Brad Miller (Member # 2) on 06-20-2008, 07:27 PM:

I want to say it was Systems and Products Engineering COmpany, but that may be wrong.

I have used the failsafe that Justin is showing. It mounts directly in place of the lower payout roller, but it only gives you two wires. You have to wire it into your failsafe. I believe Strong's payout is designed to wire right into the platter to cut power. I don't know, I wasn't impressed with either. Besides, who in the hell needs wrap detectors anyway??? [Razz]

A much better solution is Neumade's wrap detector here. It actually givs that lower roller some travel, as it can move up and down. This way when a wrap starts and pulls tight, the "elevator" can pull up as the projector is winding down to a stop without causing further damage.

Posted by Louis Bornwasser (Member # 3063) on 06-20-2008, 08:50 PM:

WE supply & continue to supply that wrap detector for National Amusements & others. On a Christie AW-3, it is wired to lift the center tap of the low voltage transformer, which cuts the power to the LED's. This effectively turns the platter off, right now. Louis

Posted by Tim Reed (Member # 137) on 06-20-2008, 09:12 PM:

As Brad said, SPECO is Systems and Products Engineering Company (formerly Drive-In Theatre Mfg. Co., or DITMCO). I still call their platters "Drive-In" platters.

The tension switch will work how ever you hook it up. It's easiest to do as Louis mentioned (thereby reducing wire runs). Just series it with the CT on the Christie transformer. FWIW, I learned that from Louis to begin with, years ago. I also loved the little AVASK units - it's easy to adjust the triggering tension by changing the springs (included).

Posted by Monte L Fullmer (Member # 2797) on 06-20-2008, 09:12 PM:

quote: Brad Miller
I believe Strong's payout is designed to wire right into the platter to cut power. I don't know, I wasn't impressed with either. Besides, who in the hell needs wrap detectors anyway???

I know of a small 4plex with A/AP3 units with these wrap detector units replacing the two lower rollers on the tower and tied in series with the leads from the machine drop failsafe.

And I do agree: not to impressed with these units.

This small plex needed these detectors since the owner is very anal on any problems and were sold by a local dealer to have these installed feeling that this what the owner needed even though the booth personnel did receive proper training in presentatin factors and maintenance procedures.

Posted by Joe Redifer (Member # 3) on 06-21-2008, 01:41 AM:

Yes, the Strongs cut power to the platter which causes the take-up to stop and the failsafes to drop. In one case you get film on the floor, in the other you have to run a wire from the platter to the projector. It's a lose/lose situation, I guess. The Strongs can at least be locked in the OPEN position.

Posted by Charles Greenlee (Member # 3856) on 06-21-2008, 04:05 AM:

Hmm, those Neumade platters look an aweful like redressed Strong platters. Hopefully Strong platters that have had their design flaws fixed?

Posted by Eric Burrel (Member # 4882) on 07-15-2008, 10:57 PM:

Having worked with the Neumade, Strong, and Christie platters, I can say the Neumades are not redressed Strongs, but more like the Christies. I personally like them better than the latest AW3s. The Neumade fail safes work very well especially in those cases of a sudden increase in tension from tape residue or someone taping the tail of a print and not removing it. [Mad]

Posted by Michael Hossen (Member # 4274) on 07-16-2008, 11:34 AM:

Our Cinemecanica platters have this as standard, I'm sure.

For example, when a brain wrap occurs the tension of the film causes the bottom roller on the payout side of the platter to lift up, which stops the projector. Am I on the right track? By the way, it works well.

Also, when the original poster said "Drive-in" projector I assumed he meant the projector at his drive-in cinema.

Posted by Tim Asten (Member # 4051) on 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

Posted by Sean McKinnon (Member # 612) on 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.

Posted by Michael Hossen (Member # 4274) on 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...

Posted by Dave Macaulay (Member # 813) on 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.

Posted by Justin Hamaker (Member # 2165) on 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.

Posted by Charles Greenlee (Member # 3856) on 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.

Posted by Jack Ondracek (Member # 1466) on 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.

Posted by Gordon McLeod (Member # 33) on 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

Posted by Eric Burrel (Member # 4882) on 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.

Posted by Jack Ondracek (Member # 1466) on 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.

Posted by Sean McKinnon (Member # 612) on 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.

Posted by Eric Burrel (Member # 4882) on 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.. [Mad]