It doesn't help that all (or most?) of the traces on the board go through internal layers, making them very difficult to trace out. It would probably help if someone with a fully working one traced all the paths out and did a schematic. My 145's board is fully working so I suppose I could, but I don't know what software I'd use to plot it all out. I've never done something like that before.
I'm lucky that the most trouble I've run into with mine is that the internal speaker on my 170 stopped working, with how many times I've had both apart.
I wonder if the "second gen" 100 series PowerBooks (160, 165, 180, color variants) are as fragile.