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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » AW3 creeping at take up

   
Author Topic: AW3 creeping at take up
Justin Hamaker
Film God

Posts: 2253
From: Lakeport, CA USA
Registered: Jan 2004


 - posted 04-26-2009 03:34 AM      Profile for Justin Hamaker   Author's Homepage   Email Justin Hamaker   Send New Private Message       Edit/Delete Post 
Tonight we discovered that one level of the AW3 at our drive-in is creeping when used for take-up. At the point where it should be stopped when the projector is threaded, it still turns slowly. What are the likely causes for this. I know one is the low pot is set too high on the motor control card.

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Scott Christopher
Film Handler

Posts: 69
From: Adelaide, South Australia
Registered: Apr 2001


 - posted 04-26-2009 04:27 AM      Profile for Scott Christopher   Email Scott Christopher   Send New Private Message       Edit/Delete Post 
Align the decks according to the manual. I had this a few times due to the LDR (could not get my low speed). Replacing the LDR solved the problem. There's a tweak guide under the TIPS section I think, that may help.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 04-26-2009 09:11 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
The tips guide is far better than the manual. The manual assumes (incorrectly) that the mechanical alignment is already correct. Louis

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 04-26-2009 10:45 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
If it has fixed centerfeeds...verify that the payout feed fingers are not binding on the first roller in the centerfeed cluster. In take-up, they swing back in that direction.

Steve

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 04-26-2009 05:04 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
Forgive the ignorance here, but what is the LDR? I've never heard that term in connection with a Christie platter before.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 04-26-2009 05:17 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
LDR = Light Dependant Resistor

You would know it as a cdS (Cadnium Sulfide) cell.

Carry on.

Steve

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 04-26-2009 05:33 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
If no luck, consider the infrad upgrade kit. Trying to get the old PC cards to work with new LED sensors (or the other way) can be, uhm, trying.

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 04-27-2009 05:53 AM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
Thanks, Steve.

So, Scott, did you replace just the cell, as in solder a new cell onto the board? Or did you just replace the whole LED/cell assembly?

John: The motor control cards should work just fine with either the visible LED or infrared. At least as far as I know. Now, perhaps if they are *really* old, there was some difference in the circuitry and they need to be replaced with current ones, but I'm not aware of that. The LED card, however, does need to be replaced when upgrading from visible to IR.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 04-27-2009 08:34 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Yea, Christie gave up on the old CDS cells as they became too inconsistant in manufacturing over recent years... some new cells were too far out of range to even work correctly! thats why the IR conversion kit... and it's self calibrating to boot. Also be sure the return cam is not broken. It's a question mark shaped nylon thingy inside the return arm mount. They become very brittle with age.

Mark

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Brad Miller
Administrator

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


 - posted 04-27-2009 03:36 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Without hearing back from Justin, we are all semi-guessing here.

First things first Justin, when you spin the LO pot counter-clockwise on that deck's motor speed control card...does the motor stop? That is always the first thing to check and 99% of the time the problem. Past that it would be a mechanical issue.

BTW Justin, don't rush out and order the new IR "upgrade" kit like Mark is suggesting. I've ranted about this for years. They suck! In fact I had to get Christie to ship out my last couple of AW3 orders with the old visible leds to get the quality level I expect from an AW3 that simply cannot be achieved with the IR kit. The IR kit makes the platter's response very touchy and it likes to sling prints around. While Mark is correct 1 in 50 of the older style will be defective right out of the box...big deal. Swapping them for a replacement only takes 2 minutes.

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 04-27-2009 08:49 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
Yeah, I was at a theater doing service work and I saw a block of foam with, like 25 of the older CDS cells in it. When I asked the operator what they were for, he said Christie sent them when the theater opened because the ones in the (then) new AW3's didn't work right. He said Christie did bend over backwards to get them running, sending all kinds of parts and a tech to get everything up. I've had CDS sensors work fine, with one type of control card, but poorly with another.

The IR kit includes a replacement filter card. But some people swear using the old one with the IR sensors works better.

So I wouldn't suggest changing out the older sensors right away, but the upgrade may be an option if you can't get them to work.

And an additional suggestion to Justin is to be sure no light is getting in behind the end cap cover.

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Scott Christopher
Film Handler

Posts: 69
From: Adelaide, South Australia
Registered: Apr 2001


 - posted 04-28-2009 05:54 AM      Profile for Scott Christopher   Email Scott Christopher   Send New Private Message       Edit/Delete Post 
Ken, I started out with replacing one complete assembly, then just rebuild the faulty ones (always having a rebuilt spare on-hand). I only had 3x AW3 platters, but just soldering a new cell onboard always solved the 'low speed' problem. If you can find a supplier of the cell, it's a fairly cheap way of keeping the platter going without any conversions. I haven't used the IR conversion so I cannot comment on them.

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