Hello James,
Welcome to Microsoft Community.
I note that you have tested this issue with another keyboard device. According to the test results, your Surface Pro X correctly recognizes your friend's replacement keyboard, and this keyboard is working properly, which means that the problem is coming from your keyboard.
Since it is not clear what recovery steps you have already tried, I will share a more complete recovery process here:
1. Remove and reinstall the keyboard.
- Unplug the Surface and remove the keyboard cover.
- Make sure there is no debris, damage, or anything that could hinder the connection.
- Reinstall the keyboard cover, making sure all magnets are touching the bottom edge of the Surface.
2. Check the connection.
Please make sure that the LED light will light up when you connect the keyboard. If the LED light is not on, there may be a hardware problem. Validation is required in UEFI.
Refer to the following support connection guidance to enter UEFI:
How to use Surface UEFI - Microsoft Support ****
If you notice that this keyboard doesn't work at all in UEFI, it means that the keyboard is damaged and needs repair.
I can direct you to Surface Live Support, who can help you create a repair order. Send your Surface to the Surface Technical Support team who have the expertise and equipment to inspect and repair your Surface:
- Use your personal Microsoft account (not your organization account) to access the following links:
- Type Surface, press Enter, and click "Contact Support" at the bottom:
- Select Technical Support and select the device model you are currently using in Produce family, then click Confrim:
- You will see contact options for Chat support and Phone support, please contact them during business hours:
However, please allow me to kindly remind you that currently we have received feedback from some users that they encountered errors when contacting through Chat support, and we are investigating this situation. Therefore, if you cannot contact the Surface technical support team through Chat support, please try Phone support and leave your contact information according to the guidelines. Surface support will call you back.
I wish you all the best.
Best Regards,
Mitchell | Microsoft Community Support Specialist