MacPro 4,1 (A1289) mother board replacement

Is a mother board the same as a logic board? Are there replacement instructions anywhere?

I have successfully bootcamped Windows 10 on a MacPro 5,1 running nvidia GPUs… OculusVR runs smoothly.

I am hoping I can replace or repair the motherboard on this 4,1, flash it to 5,1 and build a second VR station… these machines double duty as macOS / DaVinci Resolve edit bays.

Any ideas appreciated: located in Los Angeles - motherboard repair suggestions?