I got a new servo a few days back (RC Servo, Futaba FP-S148). I first tested it out with the Sweep sketch on Arduino, powering it with the Arduino 5v and GND pins only. It was working, just fine.

Today I was trying to use it in my robot and I tried powering it with 2 LiPo batteries (Samsung ICR16850 2200mAh, from an old laptop battery) connected in series, giving 8.32v. As soon as I connected my servo, it started rotating randomly, I had not connected it to my Arduino yet. I quickly took it out.

Next, I used a L7805 to get 5.13v regulated supply out of my batteries that I used earlier. When I connected my batteries to the servo, and the servo to the Arduino, uploaded the sketch, the servo started behaving rather strangely, it first did a complete turn and then stopped. Only a humming sound came from the servo. Strange thing is, whenever I connect one of my Multimeter leads to the power cables, the servo immediately turned in the opposite direction only as long as only lead was in contact with either the positive or negative wire.
Otherwise, the servo just gives a humming sound.

Have I fried my servo? Or is it some other issue?

I stripped down the servo and checked the motor. It is working fine, seems like this is a gear problem.

  • $\begingroup$ What code are you using to control the servo? Are you using the Arduino Servo library or something similar? $\endgroup$
    – Octopus
    Apr 25, 2016 at 18:03
  • $\begingroup$ @Octopus I'm using the sweep example sketch $\endgroup$
    – YaddyVirus
    Apr 25, 2016 at 18:15
  • $\begingroup$ Did you ever try putting it back on the Arduino 5V and ground?? $\endgroup$
    – Chuck
    Apr 25, 2016 at 19:33
  • $\begingroup$ @Chuck yes I did... It didn't work. $\endgroup$
    – YaddyVirus
    Apr 25, 2016 at 23:36

1 Answer 1


Yes it's absolutely fried. Check the tech specs of your servo next time.

Power requirement: 4.8V or 6V (from receiver) Power consumption: 6V 8mA (at idle)

  • $\begingroup$ Time to buy a new one I guess $\endgroup$
    – YaddyVirus
    Apr 26, 2016 at 8:33

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