These things are way beyond the abilities of the home tinkerer.
If you're lucky, it may only be a board replacement. ...but the problem is determining which one, and that's where a skilled technician's knowkledge, experience, test equipment, and access to the correct parts comes in.
You're better off either taking it to someone who knows these things or simply replacing it. I've done a lot of stuff "under the hood" in my day but there are some things I won't touch. This is one of 'em. Wisdom is knowing which windmills to tilt at and which ones to avoid.