PiDog Left Rear Leg Shaking & Burning Smell from Speaker/Robot HAT

Robotic kit for Raspberry Pi
1

Hello SunFounder Support,

I am building the PiDog kit using a Raspberry Pi 3B+ and have run into a hardware failure involving a burning smell and a violent jitter. I need some assistance with troubleshooting or getting replacement parts.

The Issue:

  1. Left Rear Leg Shaking: Initially, my left rear leg was shaking/jittering. I completely disassembled the leg, ran the servo_zeroing.py script on PWM Port 11, and reattached the plates perfectly straight. However, the shaking continued as soon as the robot powered on.
  2. Electrical Burning Smell: While troubleshooting, I noticed a faint electrical burning smell. I took off the Robot HAT to inspect the underside and discovered that the red speaker wire is melting right at its housing/solder joint.

What I Have Tested:

  • I isolated the issue by completely unplugging the 2-pin speaker connector from the HAT.
  • The burning smell stopped once the speaker was disconnected, but the left rear leg continues to jitter/shake.
  • It appears the audio amplifier circuit on the HAT may have shorted out, which is dropping the voltage or corrupting the PWM signal to the servos on that side of the board.

Could you please help me determine if I need a replacement speaker, a replacement Robot HAT, or both to get my PiDog working safely?

Thank you!

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2

Thank you for your detailed report – this is very helpful.

We will send you a replacement Robot HAT. However, before we do, we would like to confirm whether the left rear leg servo itself is still working properly.

Could you please perform the following test?

Connect the left rear leg servo (the one that was shaking) to a different PWM pin on the Robot HAT (for example, a pin that you know is working, such as the one used for another leg). Then power on the PiDog and observe whether the servo still shakes.

If the servo still shakes when connected to a different pin, the servo itself is faulty and we will also send a replacement servo.

If the servo does not shake on the other pin, the original PWM pin (or the HAT) was the issue, and the servo is fine.

Please let us know the result, and we will arrange the appropriate replacement parts for you.

3

Thank you for the quick response! I performed the troubleshooting steps you requested. After unplugging the faulty speaker, I went through the calibration and fine-tuning process again. The left rear leg servo has stopped shaking and is now holding its position correctly. There is still a slight jitter but seems to be working. I also noticed on the right front leg it started doing a little jittering as well. Testing it on a different known-working PWM port also showed the same thing. However, the Robot HAT audio circuit is definitely damaged from the short, and the speaker wires are melted. Please let me know if you need my shipping address or any further details to process the replacement. Thank you!

4

We will send you a replacement Robot HAT V5. Please contact service@sunfounder.com and provide your shipping address and original order information if possible so we can arrange the replacement for you.

5

I forgot to add the order information. I ordered the Pi Dog kit from Amazon. Order Number: 112-6896279-6393043