Hello,
Similarly, I experienced several issues with the second-hand Loona robot I purchased. Since Keyi Tech does not have technical support in Turkey, I had no choice but to repair it myself.
First, its ears malfunctioned and started vibrating continuously. After exchanging emails with the Keyi Tech team, they kindly sent me two replacement ears free of charge. Once I installed the new ears, the issue was resolved.
Later, a few months ago, the right leg motor malfunctioned, causing Loona to completely lock up. It couldn’t move up or down and kept falling backward. To fix this, I ordered an N30 motor from AliExpress and followed the repair tutorial in the video below to replace the waist motor. Thankfully, after this repair, it has been working perfectly without any issues.
The only difference between my repair process and what was shown in the video is that I removed the gear system from the new motor and attached the original gear system from the malfunctioning motor to the new one. This way, I replaced only the faulty motor without changing the gear mechanism.
I’m not a professional in this field, but you don’t need to be one either. If you have some basic technical skills and a bit of dexterity, you can do it yourself as well.