Samsung BD-J5700 (not listed): How do I replace the motherboard?

Hello amazing people!

I have a Samsung Blu-ray player BD-J5700. A few months ago it went into it's boot cycle when I turned it on, and continued booting every few seconds. I tried the remote buttons, none had any effect. I tried the buttons on the machine also to no effect. I tried unplugging it and holding the power button to hard reset the machine per instructions I found online. The machine reboots whenever it's plugged in, and that's all it does. I want to try replacing the motherboard. Has anyone done that with one of these? I have never attempted to repair any electronics before, so please address me as a beginner. :-) Thank you!