Sure enough, there's nothing there on the SSD - a surge must have been the culprit, as you correctly assessed.
(I'm usually very cautious about grounding. I still wonder if the then new battery brought the charge?)
I ordered another SSD (low storage, good speed) and will install at the same time I put in another new battery (different vendor). I did not see any other connections necessary which might make me taint the M-Board; only the SATA connect. Anything else you would suggest to be aware of/prep for other than static mat and wrist band? (FWIW, I have used the
MacFixit tool kit since introduced; it's the best, IMHO.)
I suppose if the new SSD goes awry then the M-board is faulty - and probably not worth ROI to repair (at 3 years).
Thanks for the spot-on diagnosis. Good eyes