Film-Tech Forum ARCHIVE: Failsafes

This is topic Failsafes in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ian Bailey (Member # 1752) on 02-07-2005, 08:42 PM:

I know this topic has been talked about many times but I am having a lot of trouble purchasing what I feel I need.What I want is a failsafe that will sense too much tension on the print(at the start of a Brain Wrap or any sort of jam) and then give the projector enough time to stop before major print damage occurs.A failsafe with enough "YO-YO" action to allow the projector to stop before ripping sprocket holes is what i have in mind.Do they exist and where can I purchase them or are they a one off thing that is made to suit each installation.I have heard Speco make one but they would have to be the hardest company i have had to track down to get information from.I always have trouble trying to find them on the internet.

Posted by John McConnel (Member # 2000) on 02-07-2005, 09:10 PM:

If you happen to use Kinotone platters, the fail-safe that Kinotone makes for their new platters can be retrofitted to it. I use older Kinotone platters on which I installed the new fail-safes, and while they may not have the yo-yo action you mentioned, they stop the projector before film damage occurs. Cost is less than $200.

Posted by Darryl Spicer (Member # 711) on 02-08-2005, 12:31 AM:

Those made by speco are honestly not worth the money. They caused to many false shutdowns and in some cases had to be weighted or tied down to prevent the false shutdowns.

Posted by Robert John Jeromson (Member # 2559) on 02-08-2005, 12:46 AM:

The position of the polyester reflex switch on the Kinoton ST200E platters has moved since last year it is now at the bottom of the yo-yo behind the platter as opposed to just above the top plate on the tower.

Either or is pretty effective, our ST200E have been retro fitted with an seperate yo-yo on the side of the tower utilising the older reflex cofiguration giving us a two second run down time.

I'll snap a pic later, if this is at all useful.

Posted by Monte L Fullmer (Member # 2797) on 02-08-2005, 02:48 AM:

(to all if needed) .. if you have Strong platters, Strong makes a "wrap detector" for the A3/AP3 units, whereas all you do is replace the top roller assembly with this device and wire this unit in series with the failsafe wiring on the automation board. Works like a charm and saved many a "poly" print wraps.

Chrisite has basically the same for their Aw3(R) units as well and with the same roller configuration.

One can do a search on aftermarket "wrap detectors" for their make and style of platters.

Posted by Chase Hanson (Member # 2779) on 02-08-2005, 03:07 AM:

Not much love for the Strong units. In all the brain wraps ive seen, ive never seen the Strong Tension detector stop a print before it can be damaged. These are, in practice, damage minimization units, not damage prevention units.

Posted by Monte L Fullmer (Member # 2797) on 02-08-2005, 03:12 AM:

quote: Chase Hanson
Not much love for the Strong units

..trick is, to take out that tension thumbscrew on the backside of the "wrap detector" unit, thus it'll make the device "hair trigger" happy.

Plus, one has to set the bobble rate to "zero" on the cue detector/proximity failsafe units, to work effectively and quickly.

-Monte

Posted by Ian Bailey (Member # 1752) on 02-08-2005, 04:49 AM:

I have one AW3,one old Speco(pre LP 270) and one LP 270 platter.
Robert a picture of your retrofit would be good.
I have heard that a retrofit Failsafe that has a YO-YO effect of about 1.2metres is available in OZ.They are usually mounted off wall brackets between the platter and the projector but I supppose it could be mounted on the platter tree if space is avilable.Just not sure if it will really do the job or not.If projector motors had some form of braking system(like they have on some Power Saws)then it seems that the failsafes would actually do what they are supposed to!!

Posted by John Pytlak (Member # 331) on 02-08-2005, 12:42 PM:

The ones with a "yo-yo" or "trolley" are preferred, as there is some extra film in the loop to allow the projector to coast to a stop after a shutdown. Without the slack, even if the failsafe immediately detects the jam, the inertia of the projector could still damage the perfs or stretch the film.

Posted by James Faber (Member # 2796) on 02-09-2005, 03:56 AM:

We mounted the failsafes where the uppermost roller on the tree ought to be. And, I have to go with Darryl on this one - they are not worth it. They produce was too many false shut downs, and make threading quite annoying(especially if you still have the original brain for the LP-27). Even the tension from threading will set them off and the platter will stop paying out. These failsafes have actually CAUSED brainwraps for me, although not during a show, but ANNOYING nonetheless.

Posted by Dave Callaghan (Member # 1544) on 02-10-2005, 03:29 AM:

From my experience, there are 2 kinds of wraps, gradual and instantaneous / catastrophic.

A slow feed / payout platter allows the film to gradually build up around the centrepiece because the payout is running slower than the takeup / rewind. This can happen on a Strong non-digital controlled platter. The payout speed can be corrected by adjusting the motor's position, and I believe this adjustment is explained in the manual.

I have found that the Strong wrap detector works perfectly when it comes to this sort of wrap.

A catastrophic wrap is not so certain.

Static or masking tape left accidentally causes the film to tug suddenly, bringing the feed to a halt instantaneously.

Think about it for a second, and it's anyone's guess what the state of the film will be. No matter how "trippy" the wrap detector might be, once the film is no longer feeding freely, can ANY wrap detector stop the projector fast enough to prevent film damage once it has stopped moving through the projector? A projector is a mechanical device which inherently possesses inertia. Since it can't stop on a dime, film damage seems like an inevitable consequence of a catastrophic / sudden wrap.

Posted by Bill Langfield (Member # 818) on 02-10-2005, 11:06 AM:

Ian, contact Associated Sound Newcastle.

(I'll chase up their phone number if you like - Don't have it here at home right now))

They retro-fitted all our older Speco's at the Hayden Cremorne Orpheum, with the yo-yo elevators.
But I've a feeling the mod is not really easy self install, perhaps Barry can point you to someone in your state or give some advice.

As for the claims of false trip/shut downs, I've found that only happens if a print (particularly older ones - being an art house, we tend to get some prints THAT HAVE DONE THE ROUNDS!) only happens if the print was not inspected properly at make up.

IE, not cleaning old tape splices (also where you peel the old tape of a each reel head/tail, because you need to save every frame you can, after seeing the the last 20 'projectionist's' just keep cutting another frame further in) with shell-lite or FG and removing gunk from old cue foils etc.

It's almost a good a thing. A show shuts down, then you straight away go OK WHO MADE THAT UP - Lazy shit did a crap job!
(Though in your case with the clinging etc, that wont work)

Possibly just get Film-guard (for the clinging and shreading - though Kodak blames the Vic projectors for EVERYTHING), we finally got our test set-up at GUO just the other week. Thank god all the bosses are happy with the results - As I was the one who talked them into trying it.

Bill.

PS What John said is correct. However some projectors stop quicker than others.
Centuries run 'forever', Vic-5's stop much quicker.

Posted by Dennis Udovich (Member # 1066) on 02-10-2005, 01:48 PM:

I have 13 screens, using 3 5-tier and 7 3-tier Strong platters. All are equipped with Strong wrap detectors. They work GREAT! Saved many shows. I can't be without them. The few platter wraps I encounter are from static and the wrap detectors save the show. [Smile]

Posted by Gregory N. Jones (Member # 805) on 02-11-2005, 01:51 PM:

Ian,

We do sell a platter failsafe that sounds like it would fit your needs perfectly. Maybe I'll send one to Brad so he can test it out and give you guys some feed back on it? Here is the literature sheet on it:
Neumade platter tension failsafe