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Topic: Trouble with Brand New Strong Platters

Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 09-03-2002 04:04 PM

All of them?

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-03-2002 05:23 PM

Joe, check and make sure they have a nice easy feather-touch swing with absolutely no binding whatsoever. I have experienced some binding in mine from time to time, especially if the roller fingers start dragging on the plate. A crowbar should fix that. I have had some pivot studs loose on those arms, too. Apparently the factory didn't tighten some of them down like that are supposed to be. I have received some that were just plain bent! (must have been squashed in shitment.)

Incidentally, make sure the platters are level. If they are not, the swing arms do not like it. They should practically stay wherever you set them.

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Wes Hughes
Expert Film Handler

Posts: 175
From: Raleigh, NC, USA
Registered: Aug 2001

posted 09-04-2002 12:17 AM

I agree with Paul about the feed arm dragging a tiny bit on the plate...have had that happen a few times.

In my phase control experience I have found it nearly impossible to time them so that they pay out perfectly without touching any of the feed plate bumpers for the entire show. SO, as I have said in previous threads, I time them to spec (as close as possible), then raise the motors a bit more so they are timed slow. Most of my Strongs and Potts platters will wrap 3/4 or more around the brain. I have platters that have been doing that for YEARS and I have NEVER seen any film damage from it....and no brainwraps with phase control or micro since they are timed slow.

After spending a small fortune to convert some of my platters to phase control a few years ago I am converting them, one stack at a time, BACK to microswitch as the phase control modules crap out.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 09-04-2002 02:00 AM

Too bad there is no way to convert to SCDC.

I have found a workaround and will post it in a few days if it seems to be a rock-solid method, which I think it will be.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-04-2002 02:05 AM

Let us know, Joe. We are all anxious to get those damned things to work right.

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Sam Hunter
Jedi Master Film Handler

Posts: 779
From: West Monroe, LA, USA
Registered: Jan 2002

posted 09-04-2002 11:20 PM

Just what is the theory behind platter operation?

------------------
Samual Hunter Sr.

KC5ZSL

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 09-05-2002 12:13 AM

The theory is:

1. Build up all film reels onto one of three decks.

2. Feed film out from center of roll using fancy-schmancy centerpiece.

3. Film goes into projector.

4. Film is projected and audience is amused.

5. Film exits projector and returns to platter system, taking up on different deck.

6. Show ends.

7. Repeat from step 2.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-05-2002 12:34 AM

Lower deck spins with film tail flopping around to amuse the booth cat.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 09-05-2002 12:50 AM

Sam, the first platters were called "no rewind" systems. It's effectively a cart machine without the loop splice.

73,
de KJ5KX

------------------
Better Projection Pays!

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 09-05-2002 04:22 AM

I used to have a problem with the spring-loaded arms on the feeders of Cinemecannica CNR-35 platters. The spring was designed to return the arm to its 'neutral' position when no film was passing through; but the flow of film would pull the arm, thus moving the variable resistor it was attached to and powering the motor.

I think the problem was that the springs were very sensitive to temperature variations. If you suddenly had a very hot day the spring would expand, which would make the arm reluctant to return to 'neutral', effectively running the feed plate too fast. On a cold day the opposite would happen, increasing the resistance on the arm and running the platter too slowly. I remember one very cold day on which I'd forgotten to switch the air handling unit on in one of the boxes: the first show virtually wrapped because the feeder arm was so stiff. If the temperature in the box remained steady at around 20-21, then no problem.

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Sam Hunter
Jedi Master Film Handler

Posts: 779
From: West Monroe, LA, USA
Registered: Jan 2002

posted 09-05-2002 08:35 AM

Thats pretty good Joe,
Man, that was a S.A. type answer.
HA HA.
Let’s try it this way;
The film pays out under a controlled resistance or tension.
The brain controls the take-up speed and tension.
The brain senses film tension and adjusts motor speed accordingly.
Is this accurate?

------------------
Samual Hunter Sr.

KC5ZSL

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 09-05-2002 04:13 PM

The brain does not control take up speed. Take up has its own separate control. Some platters, like the Strong, use a variac to control take up speed which ALSO controls payout speed based on the take up speed. That is very inefficient in my opinion, because then the timing of an individual deck can effect the timing of the other two.

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William Hooper
Phenomenal Film Handler

Posts: 1879
From: Mobile, AL USA
Registered: Jun 99

posted 09-06-2002 01:01 AM

It's basically a demand system.

The projector pulls the film from the center of a platter.

That film as it comes from that platter passes through rollers to create a slack segment, then through a widget called a "brain".
The brain detects by changes in that segment if the platter is moving fast enough to pay out the film at the speed the projector is pulling it. The speed of the payout platter is controlled by the brain.

Potts platters rule.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 09-06-2002 02:04 AM

Lets not forget about the 2-Ohm resistor in series with the motor used in the take-up platter. During the pay-out mode, this resistor is electrically removed from the circuit by a switch. It is very important. Without that resistor in series with the take-up motor, the pay-out will never keep up with the demand. CFS, Potts, and A-3 machines all use this 2-Ohm resistor in line with the take-up motor. I am certain you will find a resistor in series with the take-up platter in all non-digital platters where the operating reference for the entire machine is based on the take-up. The variac sets this reference.

As with any electrical/electronic device, it is necessary to establish a reference when you reverse engineer it for troubleshooting purposes.

It makes me angry when some manufactures won't release a schematic on some of their equipment. Any good technician will be able to reverse engineer practically anything on a simple PC board such as the Phase Control of the A3's. Ken ran into that snag.

Well, Mr. Engineer, We are not idiots! We will figure it out. If your design is patented, pony up, please. We have to keep some of your junk running in the field. At least make it easier for us to do just that! We are not interested in how "part happy" you are. We want to help you make it as good as it can be through our suggestons.

OK - Flame me....see if I care. I get tired of some of the I have to contend with in fixing some of your un-documented garbage.

You know it is true.

End of rant.....

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Sam Hunter
Jedi Master Film Handler

Posts: 779
From: West Monroe, LA, USA
Registered: Jan 2002

posted 09-06-2002 08:30 AM

I only ask these questions because I never fooled with one before or watched one long enough to see what was happening.
Why is it important to control payout? Is it because the film is basicaly just laying on top of the platter and would pull off if the feed speed was not fast enough or pile up on the floor if to fast?
Also according to yaw

, the takeup is kinda like a reel takeup system ie its speed is regulated by nothing more than the sound projector itself.

------------------
Samual Hunter Sr.

KC5ZSL

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