sfarrer

Hi,

I'm using Futaba servos and I have to reverse one of them using the hardwire method. Does anyone know which wires I need to crossover? It's my guess white and red? I'll assume black is negative and white or red is energized depending on direction servo needs to go. Some may want to tell me to use my controller, 6EX , to reverse the servo but that won't work in this application; read on.

It's for my 1/3 Pitt's which has two servos on the elevator. I've used the mixer on the ailerons ( 4 servos ) already.
My goal is the same angle of attack from each side which can only be achieved if I reverse one servo.

Red and White ?

thanks, Scott

TLH101

My Feedback: (90)

They need to be disassembled, and some of the wires between the board and motors need to be reversed. I'm sure of the exact procedure. Just switching wires in the plug will not work. It usually just lets the smoke out. They don't work without smoke.


If you do not have the capacity to do it in the transmitter, you might try a "reversing Y" harness. Several companies make them.

sfsjkid

I'd say Terry's method would be the easiest. He is right you'd have to open up the servo. There are 3 wires going to a feedback pot, the two other ones need to be reversed, then the wires to the motor reversed. This will affect the centering of the servo also.

gzkpez

To reverse a servo you need to open it up and switch the two wires going to the motor and reverse the two outer wires going to the pot element; thw two outer wires if there are two outer wire. If there is only one you need to put it on the unused connector on the pot. You will then need to recenter the servo, by adjusting the pot (it vaies on how from servo to servo). You will need good solder skills to change the wires, or you can have a repair place do it for you.

THIS CAN NOT BE DONE ON SOME IF NOT MOST NEW SERVOS, well at least the ones I looked at as the pot was mounted on the circut board, and changing a circut board is well just to hard to do. The Black is negative, the red is postitive; and the white is a pulse signal at plus voltage. If memory serves the pulse is from about 2 ms to 1 ms with 1.5 ms being center.

You could get programable digital servos (like a HITEC) and have one reversed at purchase or program it yourself or one of those servo reversal circuts suggested (ask about latency, it might be a problem).

I'd ask Futaba for a solution, they will have one I am sure. It probally will be another Servo Synchronizer for about 60 or 70 dollars. This will also give you better end travel adjustments It will cost, but a 1/3 scale Pitts is worth it.

Remeber always land with the greasy side down, what you do in the air is up to you.

Greg

Dr1Driver

Some servos have the motor and feedback pot hardwired to the PC board. These are extermemly hard to reverse. DO NOT simply reverse the red and black wire going into the servo. You'll burn out the PC baord and render the servo useless. Swap the two leads to the motor and swap the two outside wires to the feedback pot. This requires VERY small soldering. From your post, it sounds like you aren't very experienced with electronics. I'd leave the reversing to a more capable person or simply buy a Y harness with a reverser in one leg of the Y.

Dr.1

sfarrer

Thanks guys,

I was hoping to press " The Easy " button on this one; not so. I don't want to go on to the circuit board and do any soldering; I'll leave that for the electronic gurus. Reversing harness sounds "easy"- thanks guys!

Scott

Rodney

Another possible solution is to change brands of servos; for instance, Hiteck and Futaba servos turn in the opposite directions.

davewallace

My Feedback: (29)

sfarrer,
Since you are now getting into the bigger, more complicated models, you may want to just buy a better radio. You can get a great deal on a 9CAP used off RCU classifeds like I did. Many people are switching to DX7, making very good 9C's available cheap. I bought a great 9CAP with six receivers for $225. The 9C is so easy to program, a caveman can do it. I got rid of my older stuff, since there is still a used market at the low end. If you want a Futaba reversing cable PM me. I don't use it anymore.

Dave

sfarrer

Thanks for everyone's advice. The easist solution was to buy a special Y harness with reverse capability. The manuf. is Expert Electronics and I found it at my local hobby shop but I also saw it for sale at Horizon. Anyway, the solution was $8.95 plus sales tax, welcome to Florida. I'm glad to have this forum. You guys saved me a bundle and the hastle of opening up a servo.

Thanks again,

Scott