My 88004 servo does not move at all. Don't know how I should connect the wires correctly.

I think the inner two cables are C1 and C2 and the outer two GND and VCC.

When I connect 6.5V to the outer two cables the breadboard connector cables smoke up. I connected one GPIO from the RaspberryPI with a PWM frequency of 1200Hz to C1 and kept C2 at GND but nothing happened.

I found a video on youtube with a wiring diagram for an Arduino to 88004 but there is also GND and VCC connected with outer cables.

I orientated my Code like from the page How to control a 88004 Servo Motor with a Raspberry Pi?

Nothing happened with this Code (but I think the problem is my wiring):

import RPi.GPIO as GPIO


GPIO.setup(12, GPIO.OUT)
GPIO.setup(16, GPIO.OUT)

Left = GPIO.PWM(12, 1200)
Right = GPIO.PWM(16, 1200)


  • 2
    Can you post a schematic of your setup? Smoking breadboard connectors is not a good thing - and, 6.5V shouldn't cause any smoking unless you are pushing excessive Amps through the wires. Also, check philohome.com/pf/pf.htm for all the wiring details regarding LEGO PowerFunctions motors - for the servo you need both GND+VCC as well as C1 and C2. The motor won't move if you only use C1 and C2.
    – Phil B.
    Oct 26, 2015 at 19:50
  • My setup: RPi #16 - C1, RPi #12 - C2, 6.5V - VCC + GND
    – Matthias W
    Oct 27, 2015 at 19:58
  • so you have VCC connected to 6.5V and GND to the GND of the same 6.5V source? You will also need to connect GND to the RPi GND, otherwise there is no common reference between the VCC and the C1/C2 pins. Finally - the motor was made to run with 9V DC - it would be best if you tried a 9V source first.
    – Phil B.
    Oct 27, 2015 at 23:32
  • ok thank you now it works. there were two faults... i tried 12V and now the servo turns around. and i inverted the GND and VCC of the servo -> no smoke anymore.
    – Matthias W
    Oct 28, 2015 at 19:21
  • I've converted my comments to an answer.
    – Phil B.
    Oct 29, 2015 at 11:50

1 Answer 1


Smoking breadboard connectors are never a good thing - so check your wiring to make sure all is connected well. Also, make sure that you have the GND of your powersource connected to the GND of the RPi, so that all voltages are relative to the same ground potential. Finally, I'm not sure if the Servo will work with 6.5V - it has been designed to work on 9V. A different powersource might give better results.

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