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Author Topic: Christie AW3R Problem
Matthew McBride
Film Handler

Posts: 97
From: Tupelo, MS USA
Registered: Oct 2011


 - posted 06-02-2014 06:15 PM      Profile for Matthew McBride   Email Matthew McBride   Send New Private Message       Edit/Delete Post 
I searched the forums but couldn't find an answer for this particular type of problem. I am having an issue with my lower platter. When it is switched to normal operating mode, there is a constant audible hum coming from the column, near the control harness, and when it is switched to makeup/breakdown mode there is no more hum. These are the toggle type switches, the vintage of the AW3R is 2007. I noticed this when my bottom platter stopped functioning in normal mode, however it worked just fine for makeup/breakdown, so the motor is ok.

I have checked all of the motor cards and the LED card and those are fine too. I have also tested the LED/sensor assembly and it is ok too. I replaced the entire column control assembly from a spare of the same model/vintage and the bottom platter works again however there is still the hum. I thought it was the toggle switch but I replaced that and still the hum is present. I did notice that when the motor is unplugged the hum also goes away. I have run out ideas on what to check. I thought maybe there is a bad connection between the normal mode to the motor but not for the makeup/breakdown mode? Another reason why thought this is I detached the led/sensor assembly from the connectors and still the hum in normal mode. Any ideas. Thanks.

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Brad Miller
Administrator

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


 - posted 06-02-2014 09:14 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Turn the LO pot on the speed control card down just a touch.

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Matthew McBride
Film Handler

Posts: 97
From: Tupelo, MS USA
Registered: Oct 2011


 - posted 06-02-2014 10:39 PM      Profile for Matthew McBride   Email Matthew McBride   Send New Private Message       Edit/Delete Post 
I did just that and voila gone. Thanks Brad. Here's another question. What exactly then is causing the hum? Is there just enough current being set to the LO pot allowing electricity to flow to the motor but not enough to make it run?

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Justin Hamaker
Film God

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


 - posted 06-03-2014 12:02 AM      Profile for Justin Hamaker   Author's Homepage   Email Justin Hamaker   Send New Private Message       Edit/Delete Post 
Matt, that is exactly correct. If the LO pot was turned up just a little more then you would probably get a very slow creep. It might be a good idea to pull out your manual and check the for all three decks.

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Monte L Fullmer
Film God

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


 - posted 06-03-2014 11:45 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
One needs to do the mechanical and electronic alignment on these things.

Manual section to find the manual for these AW3R units and follow the alignment instructions. A VOM and a Platter Tach are your best friends.

Might have a bad photosensor under the deck arm. Take it out to see if any burnt traces can be seen under the glass. If so, this sensor is gone and needs to be replaced, for a bad sensor will cause some of this issue.

Also, the filter plate could be out of adjustment.

(Dang, haven't worked on a AW3R for a couple of years now since digital took all that away...but glad I can still remember how to work on these things..)

-Monte

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Matthew McBride
Film Handler

Posts: 97
From: Tupelo, MS USA
Registered: Oct 2011


 - posted 06-03-2014 07:20 PM      Profile for Matthew McBride   Email Matthew McBride   Send New Private Message       Edit/Delete Post 
I have a multimeter and I used it and the tape/stopwatch method to time/align it. I also timed/aligned per the instructions in the warehouse section in platter tips. Though I probably should redo the whole alignment procedure anyways. It's not terribly hard with the AW3's which is a great thing. BTW, I did check the photosensor when I was trying to rule things out and it is A-Ok.

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