Mode Zero

Finally I could lay my hands on a Futaba single channel rudder servo type FR-3B to complete my radio set that I owned in the sixties. Sadly due to electric( galvanic?) corrosion the original wipers partly disappeared. In order to bring it back to working order I need the schematics of the inside wiring. Some things are not quite clear to me.
Does anybody own a servo like this and can show me a photo of the inside? I know this servo was also sold in the sixties as a Ripmax.
On pole of the Furuchi motor is connected to common (green) of and the other pole connected to 1,5 V (white lead). But the instruction sheet calls for a battery pack, just for the servo, of three penlights (4.5 Volts).

The nearest Futaba servo I have is a FL-3PN, I'll find it tonight to see if it has similar internals

This looks not unlike an OS 103 rudder servo. I have a couple still in working condition. Attached are some pixs and wiring diagram. Although not the same they may give you enough to nut it out. I can strip down the 103 for more detailed pix if needed. My recollection is that one of the discs controls the rudder servo switching and the other has the contacts that connect to the motor servo.
Good luck
Cheers
John

Thanks John,
The OS servo sure does look a lot like the Futaba. The Futaba has an extra wiper for tripping the extra motor or elevator servo. It seems that the Germanium NEC 2SB220 transistor combined with a 200 microfarad capacitor is used to trip this feature.
I found a manual for a Futaba FR-3G servo (I suppose almost identical with my FR-3B) on the internet. By the way. Does your OS servo turns left and right or just in one direction, like i.e. a compound escapement?

Hi Henk
The OS servos rotate in one direction only.
John

Still a bit puzzled by the internal connections of the Futaba servo, especially how there is a difference in supply voltage for the servo ,4.5 Volt on the red lead and 1.5 Volt on the white lead, while the Furuchi motor is listed as a 2 Volt motor.
Mike, your photo of A Futaba FL3PN servo has the same color wiring it seems, so I'm still very interested in a photo and or diagram of the innards of this servo.

The OS servo Ryan, is obviously a bit different as by closer look there are two contact wheels and four plus three wipers and the Futaba has only one wheel and 5 wipers.

Another question is: can I make the wipers from brass or bronze? Mine are totally gone and I suppose the wiper blocks are custom made for the different types of servos and not available anymore.

Henk

Henk,
Here are some photos of my FE-3B servos. I hope they are of help.
John H.

Very, very helpfull. Thank you John.