Film-Tech Forum ARCHIVE: Film Wrapping Around Payout Head at Start

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Posted by Matt Hollis (Member # 2954) on 01-28-2008, 06:26 PM:

Okay, here goes:

I've got the method for threading up without the leader hitting the floor down pretty good. However, on my wonderful Strong platters unless I pull the film EXTREMELY slowly when I thread from platter to platter, the film ends up wrapping around the payout head numerous times. Is it still alright to start the movie with the leader wrapped around the payout head several times or will this scratch the leader (and possibly the start of the movie) beyond belief? By the way, I've been walking back to the platter and turning it by hand to unwrap it which is very time consuming.

I guess I should throw this in while talking about threading as well:

After I thread my failsafes and let out the excess slack on my leader, the take-up arm never wants to make it all the way back to the top of its travel. I was always taught to make sure it is at the very top to prevent film damage. Do I have to walk back around the machine to the platter to inch it up to the top or is something out of alignment with my variac?

Thanks for the help.

Matt

Posted by Mark Gulbrandsen (Member # 72) on 01-28-2008, 07:47 PM:

Yes its definately bad to have the film wrap at all around the P.O. Head, its getting scratched. Sounds like either you have the pin in the wrong hole or your platter variac is way out of adjustment. Payout whilst threading should be quite rapid and should easily keep up. Also, is this a digital or microswitch(or linear piece of crap)on the payout head?

Sounds like you need to have the platter checked by a qualified tech if there's one near you.

Mark

Posted by Matt Hollis (Member # 2954) on 01-28-2008, 11:13 PM:

We have the phase control plates.

Also, when I thread I go from payout platter, top magazine roller, back to take-up platter and let the take-up arm drop then. Now lies the problem of pulling slack to thread the projector without wrapping because the payout platter won't respond. Strong platters appear to be poorly designed for a good presentation.

Matt

Posted by Monte L Fullmer (Member # 2797) on 01-28-2008, 11:33 PM:

quote: Matt Hollis
without wrapping because the payout platter won't respond

Oh, don't hammer on STRONG too bad: IF you take care of them, pay maintenance attention them, they'll perform in an excellent way. I babysit 28 of these A/P-3 units and have all of them running quite smoothly with no problems at all.

But do agree with MARK - I bet that a tech needs to look at the main control system variac alignment in that big box at the bottom of the unit.

With the phase control ones, there could be a possibility that the phase unit inside the little black plastic cover has gotten out of alignment with one of the two screws underneath the control plate working itself loose not causing the brain to be responsive when the feed arm moves to the right.

Also for your sake: see if your people can order and install wrap detectors for your STRONG platters - they'r well worth it.

good luck-Monte

Posted by Peter David Bruce (Member # 4447) on 01-29-2008, 07:22 AM:

we have the same setup, and the same problem BUT (and this is a big but) through experience you can pull it through quickly to a certain point and it simply unravels itself from the brain unit. problem solved.

BUT obviously the payout arm is a pain, when theres even one or two wrap-rounds it makes the arm stick in one place - often, unluckily at the fastest speed point - only causing it to wrap even more.

I swear strong make a better brain unit... they MUST do!!!!!

Posted by Sean McKinnon (Member # 612) on 01-29-2008, 10:16 AM:

You should have the take-up roller cluster locked with the pin into one of the holes on the platter tree.

quote: Matt Hollis
Also, when I thread I go from payout platter, top magazine roller, back to take-up platter and let the take-up arm drop then. Now lies the problem of pulling slack to thread the projector without wrapping because the payout platter won't respond.

That is the way the platter is designed, when the take-up cluster is at the very bottom of its travel it engages a microswitch to kill the power from the variac. Instead of letting thetake-up cluster drop make sure it is still locked into the hole in the tree, that way the payout deck will still continue to feed out and you should have no more wraps.

Posted by Barry Floyd (Member # 385) on 01-29-2008, 11:08 AM:

I do mine pretty much like Sean said. When I thread up, I move the take up roller cluster up and lock it with the pin before I ever remove the center ring. I pull the ring, thread thru the brain, thru the payout roller on the top of the tree, over to and around the projector (by-passing the projector threading), then back to the take up cluster and finally to the take up deck. When pulling the film over to the projector, the microswitch engages just enough to keep the film from wrapping. If you do it right, the take up deck won't start. Once the projector is threaded, I gently pull on the film going from the projector over to the platter, and that small amount of tension is usually just enough to engage the take up deck to creep the film taught. If you do it too fast it'll start up full speed and usually snap the film or pull the loops from the sound head.

One of my platters seems to be out of time just a little. On several occasions, when starting the movie the film will slowly begin to wrap and I'll have to babysit it for about 30 minutes until the speed of the payout deck finally slows down enough and will take care of itself.

Posted by Chris Slycord (Member # 4239) on 01-29-2008, 11:09 AM:

quote: Peter David Bruce
BUT obviously the payout arm is a pain, when theres even one or two wrap-rounds it makes the arm stick in one place - often, unluckily at the fastest speed point - only causing it to wrap even more.

If that happens OFTEN, then fix your payout arm.

Hint: It shouldn't stick in one place, be it the fast point or the slow point.

Posted by Peter David Bruce (Member # 4447) on 01-29-2008, 11:16 AM:

well true we are only having a problem like that with one of our brains.

- why they call them brain units?

anyway not sure why it sticks, ive dismantled this one along with others and all is in order. its just when a few layers of film gets round it, i guess it can no longer move the arm properly.

Posted by Monte L Fullmer (Member # 2797) on 01-29-2008, 01:25 PM:

You know, there is a crazy cure to all of the 'brainwrapping' on laceup that I do sometimes: (course, don't pull the film out so danged fast through the brain on the inital pull. I've seen some crazy booth clowns literally yank that film UP and AROUND, DOWN, THROUGH so danged fast, no wonder why the poor system can't keep up with things. Sorry guys, these ain't CHRISTIE AW3 units that can handle these "Speed Racer" laceups..!! [Mad]

)

When you come back to the platter, instead of going through the entire "W" assembly, lust loop the film "over and under" the two top rollers on the "W" when you attach the film to the rewind ring. THIS way, the "W" WON'T drop, keeps the payout platter ON and FUNCTIONING so the film will NEVER wrap around the brain. Then, after all is laced up, THEN finish lacing the "W", then tighten up the film by spinning the rewind deck by hand.

This way, when your done all lacing, there is no wrap around the brain - film's all ready for for a smooth and easy payout.

quote: Barry Floyd
One of my platters seems to be out of time just a little. On several occasions, when starting the movie the film will slowly begin to wrap and I'll have to babysit it for about 30 minutes until the speed of the payout deck finally slows down enough and will take care of itself

That can probably be taken out with motor adjustment. I bet the motor is mounted way too high, causing more rolling resistance on the drive tire. Lower the motor by gradually moving the motor release arm down until it's just barely touching the underside of the deck and I bet that deck will pick up speed. Then, loosen the two 3/8" mount bolts to lower the motor down to that area where the deck speeds up. Also, a warped deck will do this also since the up and down ride of the deck will cause the motor to run at different speeds - being a vacuum motor.

good luck all - Monte