MacBook Pro 2010 not getting power at fuse

What am I missing here please? Isn't having PP18V5_DCIN at pin 1 of F6905 totally independent of whatever is happening in the one-wire circuit? I have a known good charger and DCIN board but no PP18V5_DCIN at pin 1 of F6905. How can this be?

Even I the donor board which now has U6900 and U6901 removed, I still get 16.5v at F6905 with that DCIN board so can't I assume that it is working? @oldturkey03