Well, I was not nearly that fast but did get it disassembled and back together with only one goof that I was able to fix. Inspection of the logic board back side showed no flaws that I could see with a magnifying glass. Attempting to resolder the ram slot pins would be a formidable job; there are hundreds of them in very close proximity and well beyond my solder skills. After putting it back together the symptoms are the same so at least I'm no worse off than before.
It appears that another logic board is indicated.