[NostalgiaRadioTime]

Before you give up on the speaker, you may want to check it over carefully to make sure that it didn't suffer from a broken lead going into the field coil. I will have a look at how the speaker on my console is wired, some sets had four pin plugs but one wasn't connected to anything since one side of the output transformer was often connected to the output side of the field coil so a fourth wire was unneccessary. Resistance of my field coil  won't help you, it has a 12'' in it not a 6''.
Regards
Arran

Thanks, Arran. I spent a good deal of time this afternoon checking over the speaker and it is definitely the field coil that is open. I carefully peeled back some of the paper covering the winding to expose the connections where the wires protrude out, just to be certain it wasn't a bad connection or broken wire. It's not.... where ever the break is, it's internal : All four pins are in use on the plug; the two larger diameter pins are for the field coil, and the smaller two are for the audio output transformer.