Question about Intel NUC NUC8i3BEH2 - Bean Canyon

Is there a suitable mainboard for this nuc? I can't find anything online right now... Mine is defective... Power button lights up blue for 20 seconds and then it restarts. It repeats this over and over again...the usb ports have no power and I don't have hdmi reception either. I also took out the RAM and ssd and rebooted...same problem. I also hard reset the bios, but to no avail. I removed the battery and reinstalled it. I also replaced the conductive paste on the processor... None of this helped. It must be the mainboard. It's a shame that it's already defective after 3 years.