So, I naively bought two of these JX PDI-6221MG Digital Servos thought they would work with the Arduino straight out of the box, just like MG996R did, for instance, but it seems they won't. However, I hear some clicking noise when the motor is connected, tho.

These are the Servo specs:

Dead band: 2μs    
Working frequence: 1520μs / 330hz
Operating Speed (4.8V): 0.18 sec/60° 
Operating Speed (6V): 0.16 sec/60° 
Stall Torque (4.8V): 17.25 kg/cm 
Stall Torque (6V):  20.32 kg/cm  
Dimensions: 40.5X20.2X38mm 
Weight:  62 g 
Connector Wire Length: JR  265 mm 
Bearing: 2BB

Manufacturer site: http://www.jx-servo.com/English/Product/49513727.html

Additionally, I used 5V 2.4A power input alongside with the Arduino Nano running just some sample code:

#include <Servo.h>

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards

int pos = 0;    // variable to store the servo position

void setup() {
  myservo.attach(3);  // attaches the servo on pin 9 to the servo object

void loop() {
  for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
    // in steps of 1 degree
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(15);                       // waits 15ms for the servo to reach the position
  for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(15);                       // waits 15ms for the servo to reach the position

Wiring: enter image description here

I tested the same configuration with MG996R and SG90 and it worked. So what am I missing here?

  • Care to share your wiring?
    – Majenko
    Nov 20, 2017 at 19:36
  • Added wiring :)
    – Xoyce
    Nov 20, 2017 at 21:42
  • Maybe these serves move slower and you are changing position too quickly. Try a simple sketch where you give one position and hold it for 1 second. Nov 21, 2017 at 0:23
  • Thanks, good guess, but it didn't work. I also tried to increase voltage up to 7.4V but no progress. Only a clicky noise is to be heard.
    – Xoyce
    Nov 21, 2017 at 1:07
  • i have same problem. i found that they not work with a tester. But gear is very good, sow i did take them a part and use them as gear motor, sow it is not totaly lost, but as normal servo is NO GO!!!! Jan 27, 2018 at 19:46

2 Answers 2


I managed to get servos running with 6 V and 3 A powered from lab power supply (GOPHERT CPS-1620 0-16V 0-20A). I guess, at the end, it was power supply which was crucial.


If you connect the servo to the same power supply as the MPU make sure you have a robust amperage rating. As soon as the servo tries to move, the current draw shoots way up and your MPU will hit a brownout state and reboot. At the very least you will need a capacitor at the power input to the MPU.

  • this servo is an absolute power hog. You can run it off 5V (6V is not needed!), but it's drawing 0.44 amps of power Aug 17, 2021 at 18:07

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