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Old Aug 16, 2011, 10:31 PM
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Duane's Avatar
Arlington ,Tx ,USA
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Can I hook up external servos on Cox/Nine Eagles Rx?

Lost the gears on the factory servos. I don't think I'll add too much weight, I'm only going to replace the elevator servo with a normal micro servo. I don't know how to wire it up, looking for ideas? Motor seems easy enough, two wires, but I'm not sure about the others. I hope the pic shows up ok...
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Old Aug 16, 2011, 10:57 PM
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coriolan's Avatar
Canada, BC, Vancouver
Joined Sep 2006
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Don't think you can get a servo pulse out of that board and use a 3 wires servo, but you can get a spare Rx(Receiver Set COXL5818 )for it here as it is the same as Skyranger:
http://coxmodels.com/airplanes/coxa6...ger/index.html
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Old Aug 17, 2011, 09:36 PM
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Arlington ,Tx ,USA
Joined Dec 2000
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I've seen the parts for somewhere around $60.00, way too much for it. I think the bind n fly from 9 eagles is around that. This is someone elses, and I thought maybe I could fix it. I was hoping to wire something in.
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Old Dec 16, 2011, 08:55 PM
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Servo connection for nine eagles RX

Hi all,
I have a sky eagle and lost the servo gear on the RX on the first night flying.
A dog in the local park took the plane after landing and broke the tail wing/elevator. The force knocked off the servo gear which was then lost as the dog took my plane for a wander around the park

Not wanting to buy a new RX which cost 2/3rds of a new plane. I managed to wire a micro servo to the RX board. It is possible!!!

You need to remove the original linear servo and trimpot on the PCB.
Then you can open up a standard micro servo. Run wires to the trimpot in the micro servo onto the PCB (connect in where the original trimpot was). Then extend the motor wires from the micro servo to the PCB (on the back where the original linear servo motor connected).

If the servo stalls/wont move but sounds like it's trying to move disconnect battery and reverse the polarity on the servo motor wires.

If you need to reverse the servo throw simply reverse polarity of the servo motor AND the outside contacts of the trimpot.

Hope this helps someone!!! Now you can replace the linear servo with micro servos. May add a small amount of weight but is a cheaper option then replacing the whole RX "brick"
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Old Dec 20, 2011, 09:55 PM
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Cool I need pics! I have about given up and started gutting this thing, I hope I can put it all back together.
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Old Dec 23, 2011, 03:31 AM
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Hi,
Only have a few pics hope they help. The servo is now installed and glued in so won't be able to show the finished wiring inside the servo.

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Here is the back of the rc board. I replaced the rudder servo. Unsolder the red and blue wires going to the servo motor. Remove the tiny screws that hold the servo onto the pcb. Then unsolder the 3 trimpot legs for that servo. (If you look at the bottom pic you can see where the trimpot connects from the other side). Then remove the oem servo assembly.

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Take the bottom cover off the micro servo (I haven't seen digital servos but im guessing they are diffferent!? use standard analog ones)
Remove 3 wires from the trimpot and solder on longer ones to connect to your rx board as shown in picture below. Extend the motor wires and solder onto the contacts where you removed the original servo motor wires. Refit bottom cover and then test servo direction before you mount the servo in the plane.
If the servo doesn't respond to your stick controls but tries to drive in one direction and stalls on the throw stops then reverse the motor polarity.

If the servo responds in the opposite direction to stick input (for the way you mount the servo) then reverse polarity on BOTH the motor and the trimpot outer wires only (leave center connection of trimpot where it is).
Once the servo tests ok and moves in the desired direction to the stick input you are ready to glue the servo into the plane. I found 3min epoxy works really well!
I used a small screw (cut down) put directly into the servo horn to connect the oem pushrod.

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Your finished rx board should look something like this. Motor wires are soldered on botton of pcb.
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Old Dec 23, 2011, 06:50 AM
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Quote:
Originally Posted by Duane View Post
Lost the gears on the factory servos. I don't think I'll add too much weight, I'm only going to replace the elevator servo with a normal micro servo. I don't know how to wire it up, looking for ideas? Motor seems easy enough, two wires, but I'm not sure about the others. I hope the pic shows up ok...

May be you can look for some servos as replacement. Once I went to the International Shanghai Model Show on April 2011. I found the smallest servo that only weigh 1.7g, 1.9g, but they are digital ones.
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Old Dec 28, 2011, 09:47 PM
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I think I understand now! Thanks!!!
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Old Dec 29, 2011, 09:49 AM
Sopwith Camel's Cousin
Between my tx and crashed aircraft
Joined Mar 2006
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Quote:
Originally Posted by Starry Xu View Post
May be you can look for some servos as replacement. Once I went to the International Shanghai Model Show on April 2011. I found the smallest servo that only weigh 1.7g, 1.9g, but they are digital ones.
Hobby King sells a rotary digital servo (the 5320 servo) that is "1.7g" (actually weighs about 1.9g on a scale). There is a RCGroups thread on it also:
http://www.hobbyking.com/hobbyking/s...c_0_075kg.html

http://www.rcgroups.com/forums/showt...1476183&pp=100

Hobby King also sells 2g to 2.6g analog servos (the 282 and 282A servos) that weigh a little more and have more torque.
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Old Apr 07, 2012, 03:43 AM
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Poland, Mazowieckie, Warsaw
Joined Mar 2012
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Hello I have noticed that you have quite good knowledge about Nine Eagles PCB.
Maybe you could help me with PCB in my Sky Eagle NE770B.
I try to explain my problem in this topic http://www.rcgroups.com/forums/showt...1240597&page=6

Do you have any idea how to repair it?

Thanx in advance for your help.
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Old Jun 13, 2012, 12:53 PM
WITCH HUNTER EXTRAORDINAIRE
USA, FL, Boca Raton
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