On the 5 lug strip mounted by the 9 pin socket, the outer pair of terminals should measure around 75V DC with the amp running, the inner pair of terminals should be around 175V DC with the amp running, and the middle terminal sits at 0V.
On the 5 lug strip mounted to the octal socket, the outer terminals should be 0V, the inner pair of terminals will be roughly 100V, and the middle terminal 0V.
Hi, I realize it's been almost exactly 1.5 years since I posted this -- life seriously got in the way.
I did the readings, and the 9-pin socket lug strip is actually quite wonky -- I'm getting ~0V on the outer pair, one of the inner pair reads ~110V and the other ~0V, and there's nothing soldered to the centre pin.
For the 8-pin socket lug strip, I'm sort of getting the values you learned for the 9-pin, i.e., ~75V outer pair, ~195V inner pair, and ~0V centre pin.
(I'm assuming the volume potentiometer doesn't matter here, but it was at the lowest position.)
I'd really appreciate any (more) help you could provide. Thanks in advance!