gary farmer

I have been given 5 old futaba, three wire servos(FP-S28). First, can I simply install new type J ( two wire) connectors on the red and black wires and use them with my new reciever? Next, I was also given a Futaba receiver (FP-R4F, mode II) can I just put a new channel 41 crystal in this and use it with my channel 41 futaba Sky Sport transmitter and forget about changing the connectors? Some one who knows about this please give me some input?
Thanks

florida817

My Feedback: (1)

Hi Gary,

I think all modern radio systems have 3 wire servos. Years ago there were 4 wire servos, but everything now is 3 wire I believe - positive, negative and signal.

Maybe you got hold of a battery wire with a J connector, that would be a two conductor setup that looks like a servo lead but isn't.

As far as adapting the old Futaba connector to the J connector it's as simple as cutting the old connector off the servo lead and splicing in a J servo lead. Just match the wire colors and you're home free.

Don't know about the receivers so I'll let someone else tackle that.

Tom

Maxime

If my memory is right, the R4F receiver was AM. If this is the case, it cannot be used with a FM Transmitter.

gary farmer

Thanks for the information. The planes are all in my studio, which is upstairs and away from the house and I am lazy and didnt want to walk up and look right now. But if the new servo wires are three wire also I think I will change them out and put on J type connectors.
thanks
Gary

larryflew

My Feedback: (13)

Gary, there have never been 2 wire servos. The connector you are talking about is a Futaba J battery connector with only 2 wires to the 3 spot connector. The old Futaba colors are the same as the new, so putting new wires on them should be easy.

Forgues Research

My Feedback: (7)

blvdbuzzard

Yes there have been TWO wire controled servos. Kraft and EK Logic used that setup. I have two of the OLD kraft servo's setting in the draw. This is from WAYYYYYYYY back.

Dru.

Forgues Research

My Feedback: (7)

How would these servos with 2 wires work. You need 2 wires for power, and at least one for signal.

I remember the 4 wire servos for different power level.

blvdbuzzard

I am not sure how they worked. I only know that the receiver would switch the power form positive to negative to change directions. The servos were so slow that they took for ever to swing 60 degrees. I am not totally sure that they could be called proportional.

Dru.

amcross

My Feedback: (2)

You can find data on old Futaba gear -- old servos, receivers, gyros, escs, etc....here..
http://www.futabarc.com/radioaccys/index.html

Your R4F is wide band AM, and is not recommended for use with current AM equipment as you may pick up interference.

bgi

My Feedback: (7)

Gary,

I replaced the old G connector leads on my old FP-S28 servos with new J connector leads a couple months ago. Since I didn't want a solder joint in the wire, I opened the case and de-soldered the old leads and replaced them with the new leads. Just match up the colors and they work fine. You can order servo leads for this or just cut the other end off an extension.

Yes, the old S28 servos are 3-wire.

They're not bad servos. They're a bit heavier than the new 3001 or 3004, so I put them in my GP 60 cub and they work just fine.

amcross

My Feedback: (2)

You can also purchase G to J converters if you really want to use your old servos, etc. And J to G if you want to use new equipment with old receivers.