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Author Topic: Help me solve this mystery?
Michael Barry
Jedi Master Film Handler

Posts: 584
From: Sydney, NSW, Australia
Registered: Nov 1999


 - posted 02-27-2001 12:20 PM      Profile for Michael Barry   Email Michael Barry   Send New Private Message       Edit/Delete Post 
Usually when a problem occurs, the cause can be readily deduced. Here is a case which confounds me totally. Can anyone figure this out? Here is what I found upon entering the booth:

- Film jammed in gate, hole burned through frame. One or two feed rollers from platter out of position. This part is not so rare...however, consider that:

* The payout unit did not appear to be constricted in any way whatsoever. No film wrapped around, only one layer of film coming out, and feeding perfectly.

* The elevator had dropped (Speco LP-270) and there was about 80 feet of film piled up on the floor under the platter tree.

* The feature was about two minutes into reel 5 (of 7) when this occured.

* The next performance indicates no film damage whatsoever until a few minutes before the film actually jammed and stopped. The film remains perfect until suddenly, vertical green emulsion scratches appear a few moments prior to the end of reel 4.

* A patron who was watching the session that broke down commented about the green scratches just prior to the breakdown. These were not present beforehand to my knowledge, although they could have been (it was my first night there!)

* There is another feature in the complex which exhibits the same damage. Perfect, then halfway throught the feature, exactly the same scratch pattern. That print, according to management, had also been damaged whilst playing in that same auditorium.

That's about all I know. How is this possible? Of course, had I been lucky enough to have been there, the cause would have been apparent. As I was a little too late, I am totally stumped. Maybe I am just not thinking clearly and the answer is obvious to someone else. I am eliminating incorrect threading (I can't see how the film could have survived 4 spools without any trouble). Any theories or suggestions?


John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 02-27-2001 12:40 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Is it possible a misaligned or sticky tape splice at the end of reel 4 caused the film to jump off a roller and jam? As the film jumped off the roller, it could have rubbed on the flange or another component causing the emulsion scratches.

But that wouldn't explain 80 feet of film by the platter tree. To do that, the platter would have to feed out film faster than 90 feet per minute, until a jam at the projector shut things down. Maybe an occasional random platter malfunction?

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion


Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 02-27-2001 01:43 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Clarify please. Are you running soundtrack up or down? Was the film on the floor from the takeup end or the payout end?

Paul Cunningham
Expert Film Handler

Posts: 146
From: Melbourne, Australia
Registered: Jun 2000


 - posted 02-27-2001 05:25 PM      Profile for Paul Cunningham   Email Paul Cunningham   Send New Private Message       Edit/Delete Post 
So the platter has stopped taking up nearly a minute before the film jammed in the gate, and your green scratches occurred somewhere before the gate, strange.

Was your upper loop still OK? Was your reel 4/5 splice punched through OK?

Normally the microswitches on the Speco elevator will shut everything down if it drops, at our cinema this includes the zipper and dowser to prevent burn throughs.

Paul

Paul Cunningham
Expert Film Handler

Posts: 146
From: Melbourne, Australia
Registered: Jun 2000


 - posted 02-27-2001 05:32 PM      Profile for Paul Cunningham   Email Paul Cunningham   Send New Private Message       Edit/Delete Post 
I should have also asked this, you said film jammed in the gate. Do you mean film stopped in the gate or actually jammed with lots bunched up all around it. ie was the projector still running after the burn through or was it stopped before it.

Were the feed rollers way out of position or could they still be like that from a previous accident that was never fixed properly?

Paul

Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 02-27-2001 05:56 PM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
Are your payout platters using payout failsafes. Does the bottom payout roller on tree move up on a rail or is it fixed. if the takeup quit working the pile up would occure under the projector heads not the tree. Sounds like you had what I call a static pull down occur. This is where the static actualy pulls the film accross the payout rollers into the floor. I have seen this happen. The film could have caught in a roller causing the scratches and the projector to jam. This causes the burn hole in the film and the rollers to go out of wack. If you have the payout failsafes they are either disconnected or not working properly do to a lag on the takeup failsafe on the prjector head. This problem depends on how the failsafe were set up and the type of automation you are using. As far as what I mentioned above the sudden jam in a roller could have caused the film to jerk in the payout causing this static pulldown to occur causing the 80 feet to acumulate in the floor. This problem is worse when the roller is further down on the tree. Check all of your transport rollers and make sure they are turning and all in propper alighnment. You do not want any film edges riding up on roller flangs.

Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 02-27-2001 09:25 PM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
To me it sounds as if the platter jammed somehow and then suddenly released as the projector pulled on the film.

My first suspect would be as John P. pointed out: A splice somehow got stuck. Then it let go causing the film to "snap" like a rubber band.

I have had this happen when the splicer leaves "tabs" hanging over the edge of the film. You can do one of two things:

1) Inspect the entire print and use a knife or scissors to trim the edges.

2) Use a razor blade and "skin-off" any splices that stick up from the print as it sits on the plater. I don't think I need mention the pitfalls of doing this but be SURE you only cut the splicing tape and NOT cut into the film!

Finally, I have had a couple of occurances where some idiot who had the print before used masking tape to break down the film which left a patch of "Stick-Umm" on the film. If you are in a hurry to build up the film you don't always catch those kinds of things but it pays to double check, even if it takes you a few extra minutes.

John Wilson
Film God

Posts: 5438
From: Sydney, Australia.
Registered: Dec 1999


 - posted 02-28-2001 05:14 AM      Profile for John Wilson   Email John Wilson   Send New Private Message       Edit/Delete Post 
How is it that 80 feet of film ended up on the floor? It is automated now...so why didn't the switch shut down the show? Your answer is somewhere in there. If a speco loses the take up...the payout will perform eratically mmost likely causing your burnout then by the time you got there it had rectified (or seemed to have) the payout feed therefore the green scratches.

Does the take up ride low on the platter tree? It probably does if it's a four tier LP-270. If it rides too low, the switch may have been activated which would cause the above scenario.

Get the kill switch working with the automation...


Michael Barry
Jedi Master Film Handler

Posts: 584
From: Sydney, NSW, Australia
Registered: Nov 1999


 - posted 03-01-2001 05:39 AM      Profile for Michael Barry   Email Michael Barry   Send New Private Message       Edit/Delete Post 
Sorry to take so long to respond to everyone's responses; I've been away since then...it's a long story!

Let's get back to it:

Brad: Soundtrack down. The film was on the floor from the feed-out end now that I read what Daryl wrote, although I originally misattributed it as the take-up end. The elevator had dropped; or at least it was down by the time I arrived, with film piled up under it. To wit: if the take-up failed, wouldn't film pile up under the projector? That doesn't sit right with me either...

Paul C: The upper loop was pulled tight and the frame in the gate was burned through and feed rollers bent out of position: all the classic symptoms of a feed failure due to a wraparound or two layers of film being pulled through the payout unit. The strange thing is that no constricture was evident whatsoever and the feed unit was happy. The source of the lack of feed was not apparent. The reel 4/5 splice may be suspect; unfortunately there wasn't time for me to examine it personally. The film damage (aka green scratches) start well before the join from reel 4 to 5, however. It still could have been something sticky, however.

Paul C again(!): To address your second post. It wasn't a 'pile-up' (film collected in projector at upper feed sprocket). It was all single file, just pulled tight. The rollers were way out of position, yes.

Daryl: Correct: As you point out, the pile of film should be under the projector, not under the tree in the case of a take-up failure. The bottom payout roller is fixed (not on a rail and is located quite close to the floor. I have never experienced nor could I have previously imagined a 'static payout' but your theory answers all the variables and makes perfect sense. Could you tell me more about how it works...does the static accumulate between the bottom feed roller and the floor itself, thereby drawing film to it? This would of course cause the projector to 'fight' the feed for a while, dragging the film through everything until it finally gets snagged, and game over.

Daryl, John and others: Being my first night back at that theatre since it was automated I am not sure if there is a safety cutout on the elevator or feed rollers at all. I haven't had a chance to test it to see just what was done. I will have to check to see what's fitted. No payout failsafes as far as I can tell thus far.

Has anyone else experienced what Daryl describes? I probably would never have thought of this, but it all adds up now. Daryl, can you tell me more about this phenomenon. When you say that the lower the roller is the worse the problem, I take it you're referring to the charge that builds up to the floor - is this how it occurs? Sorry if this seems obvious but I'm just trying to see if I understand this correctly.

Thanks for all the responses and once again, I apologise for not responding sooner.


Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 03-01-2001 10:50 AM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
Michael,

What I was referring to involves the payout roller. We use three deck systems that have been retrofitted with payout failsafes. A way to shut the projector down before it damagege the film and causes a burn thru. This roller is located about a foot from the floor. What can happen is the film can loop it's self at that roller if it jerks just right or you are pulling it quickly when threading. Static from the floor can pull the film downward and the speed of the payout platter can push the film thru the rollers faster than the projector is pulling the film thru. I have only had this happen a couple of times. If not caught the film will pile under the platters and the film will become dirty and scratched. Since the film is piling in the floor the weight from it could force the film to snag in a roller causing the projector to jam. I never had this problem until I installed the new payout failsafes. If possable can you take some quick pictures the next time this happens and have brad post them here. Hopefully it will not happen again.

Michael Barry
Jedi Master Film Handler

Posts: 584
From: Sydney, NSW, Australia
Registered: Nov 1999


 - posted 03-01-2001 12:13 PM      Profile for Michael Barry   Email Michael Barry   Send New Private Message       Edit/Delete Post 
Darryl,

Thanks very much for that - I think you've got it! The wonderful thing about Film-Tech - and the internet in general - is that someone, somewhere will have experiened the same kind of phenomenon, no matter how obscure.

Over-tension payout failsafes in that theatre are well overdue. I think that eliminating static from the film (using FilmGuard) would also go a long way towards preventing this again (if the film bears no static, it cannot be attracted to the floor other than through gravity).

I feel that over-tension devices should be standard equipment on platters. So much damage could have been avoided if this was the case. Kinoton platters seem to come equipped that way. They also have no 'down' rollers on payout either, which helps: after the payout unit, the film exits upwards as normal, then continues going up and across to the projector without going all the way down then back up again. That design principle alone would make 'static payout' inherently impossible on a Kinoton!

John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000


 - posted 03-01-2001 11:52 PM      Profile for John Eickhof   Author's Homepage   Email John Eickhof   Send New Private Message       Edit/Delete Post 
Hi! Actually, Both the Strong and Speco platters are factory equipped with payout overtension devices! I personally like the SPECO model best, as it allows film accumulation of about 8-10 feet while projector coasts down to a stop after it is actuated! SPECO makes this in an easy to install retrofit kit p/n 23000 and has a list catalog price of $157.00 US Generally, it takes more time to hook up the two wires to your automation then it takes to install the unit itself!!

------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com

John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000


 - posted 03-01-2001 11:56 PM      Profile for John Eickhof   Author's Homepage   Email John Eickhof   Send New Private Message       Edit/Delete Post 
I forgot to mention a simular problem I encountered with the SPECO, except this platter was feeding film too fast and allowing a pile up on floor at bottom of post before the film entered the projector! I found this was unique to the 48" Diameter disk (optional for small booths) that were equipped with the overtension failsafe,and on the top disc feed out only, and only the first 5-600 feet of film payed out!!! what happened was the weight of the film going down the post to the failsafe roller (near bottom) was heavier than the film paying through the payout head up to the to roller! So, I remedied it by moving the top roller on the post up about 4 inches! Thus, balancing the weight of the film! Hopefully this may help someone else!

------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com



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