flyerdave

My Feedback: (212)

I'm replacing my 645MG servos with 5645MG digitals and the only problem I've had is on one elevator half.These are in a H9 27% Extra 260 and the radio is a Futaba 9CAP.Each elevator half has it's own servo. Had everything hooked up,plugged in the hobbico Y-wire for the elevators and when I turned the radio on, the right elevator servo just danced up and down,I mean this thing jitters continuously.I seperated them from the y-wire and plugged each side into ch.2 individually and no jittering at all.Is this normal? The 645's that were in it never gave any problems,and I was using the y-wire with them.I am new to digitals and maybe there is something I dont know.Thanks

nedyob

My Feedback: (67)

I had the same problem when I switched to digital servo's, I ended up getting a Y harness with a built in resister and servo reverser, and no more problem. Or you can omitt the y harness and program the elevator servo throught your 9C. its easy to do and less worry about something in the Y harness going bad later.
NEDYOB

BuschBarber

My Feedback: (2)

I have seen this type of thing before, over the years. My solution was to Replace the Y harness with a new one, preferably one that is 22ga or better. What I have seen happen is one or both servos will Bounce, whenever you move the Stick to a position. It is kind of like Boing, Boing, Boing and then it stops. When you let the Stick go back to Neutral, it does it again.

Question - Dual Elevator setups usually require one servo to be Reversed. You can use a Matchbox type device, use a Hitec Programmer to Reverse one of the Hitec Digital servos, or use a Reversing Y harness. The Reversing Y harness has a circuit and a pot on one side of the Y. You use that pot to match the Neutral of one servo to the other. I find that many of these Reversing Y harnesses will Drift off Neutral and every few flights, you need to readjust them. I do not like Reversing Y harnesses.

I have had a 9CAP for many years. When I have a Dual Elevator setup, I like to plug the Right Elevator servo into Ch2 and the Left Elevator servo into Ch8. I turn on Ailevator mixing, in the Tx. I set the Aileron component to Zero so the Elevator halves do not move like Ailerons. It is easy to Reverse one of the servos and set the Endpoints for each. The second best method is using a Matchbox type device. I forget what Futaba calls it, but you can connect up to 4 servos to one channel and Match them for Direction, Neutral, and End Points.

In some instances, people using a Y harness, have put the Servo Arm, for one servo, on the Opposite Side. While this will work to Reverse the Control Surface, it usually changes the Geometry of the Pushrod and you get Differential Throw between one Elevator half and the other. This is especially true when the Elevator servos are mounted on the side of the Fuse, under the Stab, and close to the Elevator halves.

dirtybird

My Feedback: (5)

Digital servos draw more current than analog servos. They also have a microprocessor that can reboot when the voltage gets too low. You probably have a plug that has a high resistance. Try cleaning all your plugs with contact cleaner. Also use heavy duty servo extenders.
One way to avoid this problem is to use 6v instead of 4.8v