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Topic: How do I time the Christie AW3 Platter without a rpm meter

Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 05-31-2008 12:58 PM

(

- love to pick-on words there...) When I got my tach a few years ago, I only paid $110 for it from a local dealer.. but, I guess with everything else, price increases have made its mark in this area.

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Tristan Lane
Master Film Handler

Posts: 444
From: Nampa, Idaho
Registered: Feb 2002

posted 05-31-2008 03:09 PM

quote: Sean McKinnon
Also just FYI the meter I used to have which I think was from Grainger required that you multiply the reading by 2 to get an accurate RPM reading for the AW3, If it said ten RPM, that was really 20 RPM.

The same method is required for the tach that is purchased from Christie.

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 06-01-2008 10:16 AM

good to know. I did not buy the tach I was issued I guess I just assumed it was third party because you had to multiply the results.

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Brad Miller
Administrator

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

posted 06-01-2008 02:41 PM

Who cares what the tach says??? Just get a platter timed perfectly, and take readings using whatever tach you want and mark it. Geez [Roll Eyes]

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Galen Murphy-Fahlgren
Master Film Handler

Posts: 405
From: Canton, MI, USA
Registered: Oct 2007

posted 06-01-2008 04:08 PM

While we are on the topic of AW3s, when setting the LED potentiometer, I set it to 70k ohms at 70 as normal, but when I crank it open to full throttle, the resistance is dropping to 26k ohms, whereas the Christie manual gives the extraordinarily vague figure of "less than 40 kilo ohms." Is this no big deal? My platters may never have been timed to spec before, and I am trying to get a stable system with uniform timing so I can have my spare cards close to plug and play.

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 06-01-2008 04:34 PM

When you "Crank it open" the resistance is supposed to drop. To be honest I never bothered to leave the meter on and move to actuator around.

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 06-02-2008 07:23 AM

Unfortunately Brad, when you are servicing 120+ screens it is must easier to know how to read your meters properly than to make guesses through trial and error to find a measurement that you can repeat.

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Brad Miller
Administrator

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

posted 06-02-2008 08:00 AM

Sean, you mark the tach ONE TIME. From that point on you know to set the speed to your marks. Besides, I have 2 tachs from Christie and both are slightly different anyway.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 06-02-2008 08:07 AM

This thread shouda been titled... "From Which Angle Do I Pick My Nose?"

[Roll Eyes]

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 06-02-2008 10:22 AM

I agree with mark.

I piece of tape and a second hand on the watch is all you really need with the newer LED kits. A platter is a self regulating device given any kind of chance.

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Kenneth Wuepper
Phenomenal Film Handler

Posts: 1026
From: Saginaw, MI, USA
Registered: Feb 2002

posted 06-02-2008 10:58 AM

As with all self regulating devices, these machines need to have the limits preset so that the automatic control will operate properly.

Like the cruise control on your car that it will not operate below a certain speed: the platter system is calibrated in the opposite way, using the maximum or other known speed as a limit.

Calibrating the payout sensor sets the linearity of control and the limit sets a range over which it will operate.

KEN

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Michael Dolan
Film Handler

Posts: 77
From: Deerfield Beach, fl.
Registered: May 2008

posted 06-02-2008 11:00 AM

Well before everyone picks there nose let me say thank you for all tyhe advice I have been able to get most of my platters timed pretty nicely and running smoothly. Now I can sit back and pick my nose!! [Razz]

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 06-02-2008 11:52 AM

quote: Brad Miller
Sean, you mark the tach ONE TIME. From that point on you know to set the speed to your marks.

Right, but you still need to time the first system properly in order to repeat the results. Even if you put a mark on your tach you need to know how to read it the first time. Tape also dries out and falls off, and even permanent marker will wear over time. Also, you could be in a situation where your tach breaks or your traveling and forgot to pack it and have to borrow one from another tech.

It's like drawing the ISO 2969 curve on your RTA, it's a handy shortcut but you still need to know how to read the RTA.

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 06-02-2008 03:06 PM

Kenneth,

I totally agree with you as well about the linearity. I worked endlessly on AW2's in the '70's and learned a thing or two about what was needed. I never could understand the requirement for something like 32 to 36 RPM max payout speed on a gear motor that would take off on a dime and fling a print without hesitation. Of course the print could only go so far on the AW2 as the payout would keep it from falling all the way off but I had one diasterous show where the outside of a long print unraveled and got under the platter until it came to a stop.

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Brad Miller
Administrator

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

posted 06-02-2008 10:33 PM

quote: Sean McKinnon
Right, but you still need to time the first system properly in order to repeat the results. Even if you put a mark on your tach you need to know how to read it the first time. Tape also dries out and falls off, and even permanent marker will wear over time. Also, you could be in a situation where your tach breaks or your traveling and forgot to pack it and have to borrow one from another tech.

You know Sean, I timed platters with a piece of masking tape temporarily stuck to the top edge of the platter deck for well over 10 years before I picked up a tach. I never had any problem with it, and if you read the tips section that is the procedure I found works best to get the smoothest operation (and coincidentally that was written before I got a tach).

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