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Trim noise in Audio speaker

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longg(at)pjm.com
Guest

Posted: Mon Jul 14, 2008 5:05 am Post subject: Trim noise in Audio speaker

All,

I have a cabin mounted speaker setup which is fed off of a Garmin 340.

When I'm listening to the radio and run any of the trim motors (Ray

Allen), I get feedback noise through the audio system. Is there any way

to filter this or otherwise eliminate it?



Thanks

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nuckolls.bob(at)cox.net
Guest

Posted: Mon Jul 14, 2008 7:06 am Post subject: Trim noise in Audio speaker

At 09:02 AM 7/14/2008 -0400, you wrote:

 	  Quote: 	
		  



All,

I have a cabin mounted speaker setup which is fed off of a Garmin 340.

When I'm listening to the radio and run any of the trim motors (Ray

Allen), I get feedback noise through the audio system. Is there any way

to filter this or otherwise eliminate it?


	




   Sure. Start off with a capacitor wired directly across the

   motor leads (I presume they're still both white). Refer

   to schematic at:



http://www.aeroelectric.com/PPS/Flight/Trim/PitchTrim.pdf



   It's not common to have noise issues with these actuators.

   Let's assume the noise is radiated first. Try the .22 uF

   capacitor first 272-1070. Try the pair of 272-1436 if

   the first doesn't work. These need to be tied into the harness

   as close as practical . . . 2-3 inches outside actuator

   housing.



   Please let us know the results of your experiments.

   If the caps don't get it by themselves, we'll ratchet

   up a notch.



   Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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longg(at)pjm.com
Guest

Posted: Sun Jul 27, 2008 4:13 pm Post subject: Trim noise in Audio speaker

Bob,

Just a follow-up to eliminating the noise on the Ray Allen aileron trim

motor. I tested the 272-1070 first which removed some of the noise when

activated, but it was on and off. I took that off and did the six finger

test using the 272-1436. Worked like a charm. Not a hint of noise. Peace

at last.



Thanks



--------*****************************------------------------



   Sure. Start off with a capacitor wired directly across the

   motor leads (I presume they're still both white). Refer

   to schematic at:



http://www.aeroelectric.com/PPS/Flight/Trim/PitchTrim.pdf



   It's not common to have noise issues with these actuators.

   Let's assume the noise is radiated first. Try the .22 uF

   capacitor first 272-1070. Try the pair of 272-1436 if

   the first doesn't work. These need to be tied into the harness

   as close as practical . . . 2-3 inches outside actuator

   housing.



   Please let us know the results of your experiments.

   If the caps don't get it by themselves, we'll ratchet

   up a notch.

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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nuckolls.bob(at)cox.net
Guest

Posted: Sun Jul 27, 2008 6:29 pm Post subject: Trim noise in Audio speaker

At 08:07 PM 7/27/2008 -0400, you wrote:

 	  Quote: 	
		  


	


   Good data points sir. I'll file them away for future

   reference Thanks!

 	  Quote: 	
		  Bob,

Just a follow-up to eliminating the noise on the Ray Allen aileron trim

motor. I tested the 272-1070 first which removed some of the noise when

activated, but it was on and off. I took that off and did the six finger

test using the 272-1436. Worked like a charm. Not a hint of noise. Peace

at last.

--------*****************************------------------------

   Sure. Start off with a capacitor wired directly across the

    motor leads (I presume they're still both white). Refer

    to schematic at:



http://www.aeroelectric.com/PPS/Flight/Trim/PitchTrim.pdf



    It's not common to have noise issues with these actuators.

    Let's assume the noise is radiated first. Try the .22 uF

    capacitor first 272-1070. Try the pair of 272-1436 if

    the first doesn't work. These need to be tied into the harness

    as close as practical . . . 2-3 inches outside actuator

    housing.


	




        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Mon Jul 28, 2008 1:03 pm Post subject: Re: Trim noise in Audio speaker

Paul M. reminds me that the capacitors across the brushes also extend the lifetime of the brushes. If the noise appeared recently, it might be a sign that the motor brushes are worn out. Replacing the motor or brushes  should be easier than it is. And determining whether or not this is so should also be easier than it is....



But it isn't.



"Inventor: A person who makes an ingenious arrangement of wheels,

levers and springs, and believes it civilization."



        --Ambrose Bierce

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_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

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