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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › Anyone seen a 9256 slow down?
02-12-2006 06:56 PM  12 years agoPost 1
danwr

rrApprentice

Maineville, OH

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I noticed yesterday before I powered up my Evo 90 that my 9256 servo took what seemed to be an excessive amount of pressure to get to turn. When I powered the machine up I started moving the rudder stick back and forth and at first the 9256 moved incredibly slow and then after a few times back and forth it sped back up to what I would expect. I took the servo apart expecting to find it full of fuel and much to my surprise I don't see any signs of fuel in the servo. Anyone seen this before? The servo was bought with the 611 in August 05 and has never been crashed or stalled. Gain is 36% I believe.

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02-12-2006 06:58 PM  12 years agoPost 2
Augusto

rrElite Veteran

US

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That indicates your servo has gotten oil into it and the resin that holds the coreless winding cup is melting with the oil.

Coreless servos have an armature that's made out of cup-shaped windings held together by a resin. There is no core (coreless) to make it light and therefore fast. This cup shaped armature rotates around a fixed magnet and inside a case. The problem with the system is that if solvents or some kind of oils get inside the motor they disolve the resin making it into some kind of a rubbery substance that rubs against the magnet and the case slowing down the servo.

It starts slowly and people usually refers to it as "the servo getting weak".

Unfortunately the only way to fix it is replacing the motor.

Hope this helps.

Augusto.

Avant Aurora Ultimate

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02-12-2006 07:12 PM  12 years agoPost 3
danwr

rrApprentice

Maineville, OH

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Thanks for the reply. I read this post of yours in another subject. What throws me is that I see no sign of oil or anything inside the servo after having pulled it apart.

Is there even a way to keep fuel and oil off of the tail boom mounted servo? I've read post after post with no options.

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02-12-2006 07:49 PM  12 years agoPost 4
DOKEY

rrProfessor

Northamptonshire UK

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Oil will just seep in anywhere, best option if possible is to mount the servo up front. (something I must get around to doing sometime)

Ryan.

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02-12-2006 10:52 PM  12 years agoPost 5
Augusto

rrElite Veteran

US

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danwr,

You would have to open the motor itself to see the inside windings.

Augusto.

Avant Aurora Ultimate

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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › Anyone seen a 9256 slow down?
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