Film-Tech Forum ARCHIVE: Timing older AW3 at 45 degees

This is topic Timing older AW3 at 45 degees in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Michael Rourke (Member # 1142) on 05-25-2002, 09:43 PM:

I am having a lot of trouble timing the older towers at the 4 plex I work at. They were bought used over 20 years ago and I am swapping out parts left and right so it's becoming increasingly harder to time them perfectly.

I usually set it for 22 rpm at 70 and 2 rpm at 20, and 28-30 at full speed. When I start the feature the film will run along the post and will not compensate by going faster. I cleaned out the platter hub and found a lot of hair and broken platter work light bulb glass so I figured that was defenitely the problem but it wasn't. Then I saw that the bottom plate on this brain had a slash mark depicting 45 degrees and wondered if there was a certain speed that you would set that for because that is where the speed arm is "hanging out" with an utter disdain for the film running along the post. Would I make that adjustment on the LO or HI pot? Would an adjustment of that sort make the 70 or 20 degree setting too fast? Should I get new motor control cards and start over?

Thanks for your help, Mike.

Posted by Brad Miller (Member # 2) on 05-25-2002, 09:50 PM:

First things first, level your platters with the "V" or "U" shaped legs.

Since you have the older stationary brains, insert a screwdriver behind the two white film stripper rollers and unscrew the half circle dust shield and remove. Now remove the payout arm (one screw). Next remove the main black brain plate (two screws). There on the top of the axle you will see a small black helmet shaped piece with a fine spring inside of it (the payout arm connects to this part). You need to loosen that spring one (sometimes two or sometimes only 1/2) of a revolution so that the film will not "drag" around the backside of the brain. Reinstall and verify the payout arm does not snap back quickly to 0 degrees. Be forewarned with the older decks and springs, you may have to spend a while with trial and error until you get a feel for just how much to loosen that sucker. Since this will be your first time, you might get lucky and hit it on your first shot, but you could also be playing with it for a good half hour too. (That's a hint saying "don't do this between shows, wait until the end of the day.") In the end, you want the payout arm when reinstalled to not "snap back" to 0 degrees, but to "float" gently back to 0 degrees on it's own.

Turn the platter's power off. Remove the speed card from the deck to be timed. Put something in the brain of the deck to be calibrated so the feed arm is sitting on 100%. Insert a multimeter's test probes into the two connectors fartherest away from the platter decks. Turn the platter's power back on. Read the resistance and adjust on the led trimpot card to 25 ohms. Turn the platter's power back off. Reinstall the speed card. Turn the platter's power back on. Start the platter running at full speed and adjust the HI pot for 5 3/4 revolutions per 15 second intervals (put a piece of tape near the outer edge of the deck for reference). Set the platter to full stop and adjust the LOW pot to the point it starts creeping, then back off a tad so it does not move. Double check to verify the LOW adjustment did not alter the speed at full throttle and in most situations that will yield very nice results without further tweeking. If you can lightly tap the payout arm into a higher speed and the speed increase does not have a noticeable "bump", you're ready to roll. If you notice that within a 10-20% frame of the payout arm the speed has a noticeable increase, you're not done and you must adjust the LOW pot until you get that payout smooth.

If you have a lot of AW3 or AW3R platters in your booth, consider buying one of Christie's platter tachometers. They allow you to precisely time a platter system in only a couple of minutes. They are wonderful!

These timing instructions work for AW3Rs too, but in order to adjust the payout arm backtension spring you have to remove the 4 bolts mounting the axle to the arm and remove the assembly and work on it inverted on a table with good lighting, then reinstall.

If you have the auto timing kit (the led cards will have resistors in place of a trimpot), you mine as well give it up and order the "visible led" kit. You will never achieve a smooth payout (at least what I call smooth) with the auto timing/infared leds. The only prints I've ever thrown on a Christie platter were on units that had the infared led kit installed. Remember, "auto" is not always better.

Posted by Joe Redifer (Member # 3) on 05-25-2002, 10:25 PM:

The Christie AW3R platters are the best platters in the world (the ones with the smooth deck and not the one where the axle sticks up 1/4 inch. But that can be fixed easily for about $13 or so for a 12 plex). But with that auto timing nonsense installed I think would rather just have a Strong platter. Of course I haven't used the latest version of the Strong platter with the flashing LED's in the brain and the super high tech computer hook up, internet connection and toilet paper dispenser etc etc etc. But the ones with the LED brains (not microswitch) that we had at Greenwood were pretty good for the most part. No flashing lights but they still worked well. Strong still needs a redesign on the brain. Pat if you are interested please ask and I will show you how you can make your platter brains 100 times better and it will cost you next to nothing in manufacturing. Threading the thing would be quicker, easier and far more enjoyable than the current "design". You can do it with the current parts.

Posted by Manny Knowles (Member # 1171) on 05-26-2002, 12:54 PM:

Brad:

Could you post a pic of the tachometer? And please tell us a little bit about how it works..? I'm definitely interested in getting one of those!

------------------
~Manny.

Some people can read "War and Peace" and come away thinking it's a simple adventure story while I, on the other hand, can read the ingredients on a chewing gum wrapper and unlock the secrets of the universe.
Lex Luthor, "Superman: The Movie"

Posted by Michael Rourke (Member # 1142) on 05-26-2002, 01:36 PM:

I have the tachometer, they are about 50 bucks Manny, and they read half the rpm that the platter is spinning at so you just double it, it is a must have for a tech like yourself.

So there is no adjustment for the 45 degree hash? I thought that was the answer. Oh well, I'll try it your way Brad and let you know how it went, thanks a lot.

BTW, Why do you say "mine as well," instead of might as well? Is that a Texas thing?

Posted by Joe Redifer (Member # 3) on 05-26-2002, 04:00 PM:

Must be a Texas thang because I've never heard "mine as well" before I met Brad either. It's always been "might as well". Maybe Brad is evil.

Posted by Brad Miller (Member # 2) on 05-26-2002, 08:56 PM:

Naw, it's just cuz we Texans occasionally slip into a state of stupidity when we talks.