# Fixing the Unitree A1 Robot Dog Leg Motor

For some reason the rear right calf motor is dead...

<figure><img src="/files/jz49FfXG1X8TgGWdG1fu" alt=""><figcaption></figcaption></figure>

Initially I was looking these screws to figure out how to disassemble the leg structure

<figure><img src="/files/Oo9aQ7zTjotm9Lzs0HDd" alt=""><figcaption></figcaption></figure>

Turns out we don't need to touch those. Instead, the leg is mounted with the screws around the motors.

The leg is tricky to work with, since the calf joint and the hip pitch joint is very close together, and there's not much room to insert the tools.

<figure><img src="/files/Y61Yha7p8n94THSx7mSy" alt=""><figcaption></figcaption></figure>

I've later talked with the USC ppl, and they suggested that we can take a L-shaped hex wrench and cut off the extra length. A normal metal saw should do the job.&#x20;

Haven't attempted this yet.

Since initially we could not remove those screws, I decided to remove the screws holding the actuator together, to see if we can diagnose anything.

<figure><img src="/files/r99B3JHLGQunpFsXQjuc" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/SS324rdrR09r5Zcn3iWY" alt=""><figcaption></figcaption></figure>

Driver board seems fine...

<div><figure><img src="/files/SWnObHgCrIjCql7K5ZT9" alt=""><figcaption></figcaption></figure> <figure><img src="/files/oko2eM7xoC46Krxy6Ztq" alt=""><figcaption></figcaption></figure> <figure><img src="/files/dt3zVeCSUmUoYAlljyt4" alt=""><figcaption></figcaption></figure> <figure><img src="/files/lO8olDDU51DfVuv7Zs7S" alt=""><figcaption></figcaption></figure></div>

Later with a newer hex wrench we were able to remove the motor.

<figure><img src="/files/srC5g7Eh4Dv1lNRPi3hc" alt=""><figcaption></figcaption></figure>

Always remember to take a photo before removing these signal cables, to remember which cable plugs where.

<figure><img src="/files/aOQYK02Abx3Gz3R3457q" alt=""><figcaption></figcaption></figure>

## Update

<figure><img src="/files/c27Q6woFxXWzEyCiih8X" alt=""><figcaption></figcaption></figure>

We got the spare leg from USC. Now the dog is working.

Thx USC.

<figure><img src="/files/qhWFlVNU56MGpJ6kS9b2" alt=""><figcaption></figcaption></figure>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://tk233.gitbook.io/notes/mechanical/dog-stuff/fixing-the-unitree-a1-robot-dog-leg-motor.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.