update 3. my replacement board got ‘zapped’ when the magsafe connector was at a weird angle and shorted. At this point i think it was the age and/or wear and tear and/or non-OEM nature of the magsafe connector coming off my wall-wart and also the cheap used replacement board i got. I replaced the power mini-board with a newer one and the magsafe connector on the wall-wart with a newer one, and everything seems OK so far. It is true you can skip most of these steps and just unplug the video connector and gingerly slide out the magsafe board, but its a bit tricky and im glad i went through the whole thing.
Note 2 - Another interesting tangential note about this repair is there seems to be a situation with dodgy connectors on the internet marketplaces. The repair guide is excellent and everything works, but my own personal charger-brick side aftermarket connector is glitching out on occasion if not plugged in precisely in the right position. Once it even started ringing at high frequency and got rather hot. I’m not sure if its used connectors with mechanical wear or if its sub-standard parts on the secondary markets or what.