Film-Tech Forum ARCHIVE: Strong Platter Flinging Film Off During Credits

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Posted by Allan Van't Padje (Member # 5344) on 07-09-2009, 10:21 PM:

Hi Guys!

I'm new to the film-tech forum (definately not new to the website though), and just wondering if anyone can help with a problem with our Strong platter.

Our middle plate seems to be paying out too fast, but only during the credits of an average 2 hour film, causing it to 'fling' the film around. I've replaced all the motors fly wheel rubbers, re-adjusted all the motors and they all appear to be running similar speed (I engaged all the plates onto rewind and placed markers on each plate to tell if they are running at similar speed), the middle plate is ever so slightly faster, no matter how much I try and adjust it. Any suggestions appreciated. We've been running these platters for 12 years, never had any problems, so never really paid much attention to them, so don't know an awful lot about them (and the manual is next to useless).

Thanks, Allan [Smile]

Posted by Randy Stankey (Member # 64) on 07-09-2009, 10:28 PM:

Are they the kind with the electronic (phase control) payout circuits or just plain microswitches?

If they are the microswitch kind, have you checked your variac adjustment? (Zero adjustment.)

Check that then retime all three decks.

These procedrues are pretty straightforward.

All the information is in your manuals.
If you don't have the manuals you can download them from this site. Click on the "Manuals" button on the left of your browser window.

"Zeroing" the variac involves adjusting the linkage between the takeup elevator and the variac shaft so that the maximum speed and the cutoff point are correct.

"Timing" the platters involves running all three decks at the same time and adjusting them to be sure they all spin at the same speed.

My guess is that your middle deck is spinning faster than the others.

Posted by Allan Van't Padje (Member # 5344) on 07-09-2009, 10:49 PM:

Thanks Randy!

We are using plain microswitch. I'll download the manual as all our manuals are fax copies and probably missing the most important pages and I'll check the variac adjustment (our techs serviced the platters 6 months ago, so didn't think about the variac).

Posted by Tom Inglis (Member # 5181) on 07-10-2009, 03:00 AM:

to me, that sounds like a speed problem, pure and simple. We check platter speeds every two months, to ensure they don't need retiming, and i'd say we probably retime every platter every 4-6 months.

Posted by Brad Miller (Member # 2) on 07-10-2009, 03:20 AM:

For those who are serious about eliminating the problem...

Posted by Frank Angel (Member # 248) on 07-10-2009, 07:41 AM:

I don't know, you look at the platter ring and it seems so logical and simple that it almost seems like it should be part of EVERY platter design....like seatbelts on a car or handrails in stairwells. No one designs building and let's the buyer put in handrails as an option. Hell, if I were a distributor, I would have a "no ring; no print" policy. No prints shipped to theatres that don't have safety rings on their platters. How much could a ring of plastic like that cost? Whatever it is, it certainly is cheap insurance.

Given the catastrophic damage that can happen when a print is thrown, one who assume platter manufacturers would have incorporated rings and made them integral to their platter design by now. There are all sorts of other failsafes manufactures have used in platter design -- so why is something that it so simple yet makes it completely impossible to turn a print into estar spaghetti not become universal? Even a civilian could see that the rings make perfect sense. So where are they?

Posted by Don Sneed (Member # 955) on 07-10-2009, 09:46 AM:

Sound like the variac, check the movement of the take up carriage (the rollers on the rear for take-up the "W" as some projectionist calls it)if it moves more than an inch the variac is going bad, the variac can be rebuild under $100.00 USD, I do it all the time, very simple, takes 15-mins. if the travel arm is moving more than a inch the plate is burnt & the contact is probably gone or worn down...if this is OK, remove the feed arm on the brain & oil both bearings, even through it moves freely, the film can feel the drag & can cause this to happen...If only on one platter, than it's a motor speed problem, adjust the motor in question or replace it, good luck on your mission...

Posted by Pete Naples (Member # 761) on 07-10-2009, 11:05 AM:

My £0.02's worth.

The 'timing' procedure in the manual is not teh best method.

I ignore all the instructions about the decks being within 1/4 turn of each other after 10 turns or whatever it says.

Having electrically zero'ed the variac I then set each deck in turn to the SAME (not similar) speed, using IIRC 30 RPM as a reference. This is with the take-up dancer or 'W' as Don described it locked in the lower (fastest) of its two positions.

With the decks timed I run some film, if it's ok, then the job is done, if not then the pay-out module needs attention. I've never seen one with the microswitches over here, so I can't comment. With the LED phase control units I switch off the booth lights, removed the cover from the PCB and adjust the LED current until it runs smoothly.

I've set up countless numbers of Alpha platter this way, and it works very well.

Posted by Louis Bornwasser (Member # 3063) on 07-10-2009, 12:36 PM:

I do much as you do, Pete.

Using the top hole, I set the variac where each deck just barely creeps (24 inches per minute). The take up portion is now finished unless there is a wide speed difference on the 3 takeups.

On feed out microswitches, most are set incorrectly. The correct spot is where the switch has the maximum possible mechanical leverage. Then rotate the switch so that the click occurs in mid travel; bend the arm if required. Louis

Posted by Monte L Fullmer (Member # 2797) on 07-10-2009, 12:50 PM:

Sounds like you got a bent deck.

That will cause the takeup roller assembly to oscillate up and down since the motor rises and falls.

And when this roller assembly goes up and down, it's actually turning and shutting down the platter assembly.

And when it comes on, the speed is at full power and it could throw the print.

-Monte

Posted by Joe Redifer (Member # 3) on 07-10-2009, 02:59 PM:

Be careful about using the Film-Tech Platter Safety Ring on Strongs, though. Not each deck is the same size!

Posted by John Wilson (Member # 269) on 07-10-2009, 08:17 PM:

And definately don't use them on a Speco. [Wink]

Posted by Jarret Chessell (Member # 5077) on 07-11-2009, 02:19 AM:

just a random thought...
I remember someone once telling me they had trouble keeping film on a platter because someone in the booth had used pledge on all the platters to clean them. Perhaps someone spilled something on the deck and wiped it up with an inappropriate cleaner? (just tossing it out there)

Maybe film guard is good for cleaning platters? [Razz]