[Guest]

I've restored two Philco Model 90s with the single type 47 output tube and now I'm working on one with push pull type 45 output tubes. The former have three-wire speakers with a four pin connector; one pin is not used. The earlier model with the 45s has a four-wire speaker and I have no continuity in one of the speaker pins (not the same pin not used with the later type 47 model 90s). Do I have a problem or is this normal? Since the open pin on my four-wire speaker is not the same open pin on my three-wire speakers, I don't want to simply test my four-wire speaker by plugging it into one of my restored model 90s having the three-wire speakers.