Hello again, my sincere tnx & no apology needed! Problem solved, I had been seeing a black wire as the brown wire. As it went into the motor area, I couldn't see much. Anyhow, when I tried the old "straight pin" continuity test, I realized my mistake and found the brown wire leading me to remove a cover that revealed the missing upright switch, and the location of the cam & spring. So, I guess I just stopped stripping it down 1 step to soon!!!! I knew the brush motor and PCB were OK, so it had to be an open somewhere. I can sleep better now.
Yes, it's a complicated unit & I'll look into the link you sent.
Again, my sincere appreciation for your kindness. By the way, this yank was married to my (late) English Rose for 50 yrs!! I was at 3 USAF bases in the 50s/60s era. I owe you a pint!! Bill