[Guest]

That was what I thought.

I think I know however where the mistake comes from.

The same exact 8.5" base speaker is used in Model 70. Sometimes they are listed as "Model 20 70 90" speakers.

But the XFMR installed on that speaker is no-centertap, as Model 70 uses Class A output cascade.

I will probably have to disassemble the XFMR to see if a wire got torn off. I just wonder...seems to be "built-like-a-tank" assembly - very hard to move the wire bundle at all, let alone to flex the cardboard solder contacts for the wire inside to break loose.