You are proposing to repair a
consumer appliance?
And you describe yourself as "a total novice when it comes to circuit boards".
And you attempt to post links to a forum that requires a login to view it?
OK, I am not just trying to be harsh, but repairing a switchmode power unit in a treadmill is a major challenge to the best of us.
Whether or not I am in that category, the said power board from a treadmill which was handed me by a colleague a few years ago (in the absence of the
actual treadmill or needless to say, any information) with a view to my repair, is still sitting pristine in my trophy cabinet as an object for contemplation.