41 New servo's not working! Why? - TowerPro SG-5010

rvdokkum

I'm using the ''Propeller Servo Controller USB (#28830)''
to control servo motors ''TowerPro SG-5010''

i use a switching adapter of 5V 4A as power suply connected to the servo controller board.

from the 48 servo's i ordered only 7 work.

the others just sit still and make very small random movements.

To test the servo motors i use the ''Parallax Servo Controller Interface v0.9h Beta''

where do i start to clear up this mistery?

all help is welcome,

greetz from Amsterdam / The Netherlands.

erco

Have you tested all the servos on another controller, or on an RC unit?

Are they new? Where did you get them from? Did you ask THEM about your problem?

schill

Try putting a resistor inline with the signal from the board to the servo (typically the white wire, and labeled W on the PSC). There are several threads discussing this. Here is one of them:

http://forums.parallax.com/showthread.php?118121-Digital-servo-s-on-USB-servocontroller&p=862005

This problem can be caused by the level converters (5v <-> 3.3v) used to buffer the signals to the servos. The recommended value is 5K ohm or so. I have used 10K 1/8W resistors successfully.

In my experience, some servos have worked fine "out of the box" and others have required the resistor.

GordonMcComb

At the risk of overstating the obvious, have you checked each servo individually? I can't imagine 41 out of 47 servos in a batch being bad, but that's where I'd start.

-- Gordon

rvdokkum

1 k resistor in line with the signal did the trick.
all 48 are working. also the ones that did not need the resistor.

as i see the staff David Carrier explain in this post :
The Propeller USB Servo Controller cannot drive loads less with than 5 kΩ of impedance.