Futaba s3306 fails, hiteks work


I am new to controlling servos, so bear with me. I am controlling 8 servos via the controller. The controller is receiving serial input from my basic stamp 2. There are 6 hitek servos and 2 Futaba S3306 ‘hi torque’ servos. I can get the hiteks to work just fine, but no matter what command I issue to the futaba’s they always move only CW about 30 degrees. I can’t get them to move any other direction. I’ve triple-checked connections and all seems fine. The indicator on the controller is solid yellow, but flashes green when receiving the commands. Also - what code should I use to reset the controller? I use LOW 1; HIGH 1 … is that correct?? (pin 1 is connected to the reset pin on the controller)

An example of my test code - trying desperately to get the servo to do something: (Baudrate = 84)

SEROUT 16, Baudrate, [“starting ServoTest…,”]
SEROUT ServoRCV,Baudrate,[255,5,128]
PAUSE 1000
SEROUT ServoRCV,Baudrate,[255,5,0]
PAUSE 1000
SEROUT ServoRCV,Baudrate,[255,5,254]
PAUSE 1000
SEROUT ServoRCV,Baudrate,[255,5,128]
PAUSE 1000

The above code simply makes it jolt forward 4 times. Yes the jumper is on.

Any ideas??


What are you using to power the servos and the controller, and how are they wired up? Are the servos and the logic side of the servo controller share a power source? Does the yellow LED come back on after one of these 30 degree twitches?

It sounds like the high-torque servos could be drawing more current than your power source can supply. If that’s the same source you’re using for the logic side of the servo controller, the resulting voltage drop could be resetting the controller, producing the type of behavior you’re seeing.