I recently had trouble with spot lock on my minn kota v2 constantly disconnecting. Around the same time this happened I also noticed that my I pilot steering was acting up. Pressing the button would result in it turning properly and then other times not turning at all.
Long story short. I determined that the little motor was seizing up and drawing to much power which in turn would cause the spot lock to disengage.
I bought the turning motor online (complete unit, including the housing.. didn't want to mess with all those internal gears and it worked like a charm.
Turns like brand new and the spot lock works flawlessly. Had nothing to do with the board.
Thought I would post this to help anyone out that may be experiencing the same issue.