I have a Falcon2 Pro 22 watt diode laser. I came across a user who asked the same question, how to replace the Y-Azis belt, and he still had no reply. Any pointers will be appreciated.
I also could not find a video directly, I suggested it to someone to make one, some other videos also should be remade for current FDS versions.
Generally most tutorials for the Falcon 2 (non Pro) also apply as the middle part besides the enclosure is quite similar, but I could only find videos for the older first generation one.