hi guys i have an old glider with sanwa srm-102 servos in it which i want to use in another plane.these were driven by a 29 mhz am receiver. i have upgraded to 36 mhz ppl but the connection for the servos are different does anybody have experience with these servos


george

my bet is that they are old airtronics style servos.

All 3 wires are black with one having a white stripe?
The plug have the same pin spacing as your newer servos, but there's 3 "fins" on the plug keeping you from connecting to the receiver?

If the answer to BOTH is yes, then the way to plug them in is:

(First verify that the battery for the old radio had + at the white wire and - at the center lead... just to be EXTRA sure I am correct)

Swap the white stripe wire with the center wire at the plug and shave off the "fins"

The wire that used to be at center is the - (black for Futaba, brown for JR) The white stripe wire is + (red for Futaba and JR)

**************

That all assumes I have guessed correctly about your plug....

Cox-Sanwa radios were Airtronics compatible over here in the US in the 1970's and early 1980's.

fhhuber thanks for the reply on closer examination of the plugs they are numbered 123 from left to right.1&2 are black wires 3 is red.the battery plug goes into the 2&3 position with 3 being the +.thanks for the info i will experiment a bit and see if i can get them to work on my new receiver
thanks again george

as long as you don't get the + wire plugged in the wrong place you won't fry anything.

Sanwa is the manufactuer for both Airtronics and Cox radios.

Their old servo plug wiring is different from industry standard and was unpopular.
The battery positive wire is on the outside and the negative on the center of the plug, exactly opposite from other radios, and it will fry if connected to other brand receivers.

Airtronics finnally changed the wiring to conform to industry standard about two years ago and the new servo plug is now interchangable with JR, Hitec, Futaba.

Thanks for verifying that Sanwa = Airtronics.

I have done the converson of Airtronics plugs to make the servos work in Futaba and Hitech recievers. Get that + lead to the center and shave the "fins"... it works.

Note that if you "trade" the - lead with the signal lead instead of trading the + with the -... you can fry the servo's IC chip.

You can stull buy conversion "extensions" that let you plug the old airtronics servos into the modern "universal" receivers. If you buy one... you can trace which wires to swap and be 100% sure.

Perhaps this sticky will help.

Bill

thanks guys you have all been a big help .again many yhanks
george