Wanted:schematic for old Heathkit 4 wire servos.

[Rodney]

I have inherited several old Heathkit 4 wire servos. They use a capacitor for feedback rather than a potentiometer. They also use a center tapped 4 cell supply with the motor going to the centertap of the battery pack and the other pole being switched between the positive or negative terminal with the electronics. I won't be using them on a plane but would like to get them working again just out of curiosity. They also have linear travel, two arms that slide, one goes oneway while the other goes the opposite direction with signal. If anyone has an old schematic of this servo, I'd like a copy if possible, thanks.

[Miami Mike]

Maybe it's here:

http://www.vintage-radio.info/heathkit/index.htm

If not, try these other Google hits:

http://www.google.com/search?hl=en&safe=off&rls=GGGL%2CGGGL%3A2006-16%2CGGGL%3Aen&q=heathkit+schematics&btnG=Search

[pmackenzie]

Someone else posted this.
Looks to me like the servo itself only has part of the circuit.
Pat MacKenzie
edit - actually,on closer inspection perhaps it is all there.

[Rodney]

A great big thanks to both of you. I think the center schematic from pmackenzie is the correct one. Now I will see if I can get these to working. Thanks again Rodney

[Magico]

Very good!!!!!!!!!!!!!!!!!!!!!!!!