I can now confirm the part is the AD92-02282A. Following this guide worked very well and saved me risking $800 on ebay for a used nx500.
Nevermind, the parts are available at Samsungparts.com.
I believe the particular part of interest is the AD92-02282A, although I'll write a followup if this is not correct.
How do you actually get the mainboard for replacement? Is it directly through Samsung?