U3419W, where can I buy a new replacement main board?

I have a U3419W curved monitor connected to my Lenova Yoga Chromebook via USB-C.

This worked extremely well for a while but now if anything brushes the USB-C cable near the monitor the video stops working and the speakers make loud clicks. If I move the cable around I can get it to work again but any touching of the cable and the problem returns.

I've tried a replacement cable and get the same results. I'm pretty sure the USB-C connector on the main board has cracks.

What is the part number for the main board and where can I get a new replacement main board? I do see a used one on Ebay but if I am going to replace parts I would prefer to use new parts.

Thanks in advance.