Sir Mike e C. . . . .

Feast your eyes upon this information below and see how the drawing of the speaker is relating you your sets circuitry.

Within the field coil area of the speaker there is the sole winding of the giant electromagnet of the field coil mounted
with its input wire [ RED ] and its output wire[ ORANGE ] that is both creating the magnetic field for the speaker and
additionally . . no extra charge ! . . . functioning as a filter choke, for the power supply, since it is inserted in line with
the B+ supply.( [ RED ] and [ ORANGE ] reference squares.)

It is totally insulated and isolated from any grounding or additional windings...

Ahemmmm . .with just such of a winding presence, being in the form of a hum bucking winding / coil , which consists
of some calculated turns of a heavier gauge wire. (Since it is soon to be associated with a higher current level path )

That winding then is then placed in series between the AF output transformer and the voice coil winding of the speaker.

The principle being . . . that if there is less than optimal filtering of the B+ supply there will be a residual level of 120~ ripple
present in the audio from the sets speaker as a low back ground hummmmmm.

Look now and notice that hum bucking winding [ BLUE ] [ VIOLET ] is being connected in series opposed phasing relationship to the voice coil winding [ VIOLET ] [ GREEN ] of the speaker.

You no digga that ? Well then, lets put it in the basic initial inelligentia gatherings of a 5 year old . . .ME . . . It seems like just
after the disassembly of the end of my uncle's Never Ready flashlight, that I then had the batteries fall out.

This was all new to me, BUT, knowing that I RAPIDLY had to get those back into the unit before anyone discovered what I had done.

I could just see Spank City coming up on the horizon! Needless to say, out of four possible combinations of the 2 cells, I initially came up with a non working unit.

So what I did was put it back up . . . from whence it did initially emanate forthwith . . . like I had NEVAH-EVAH seen that unit !

I just bet you have it figured out now, a pair of 1.5 volt flashlight cells arranged as . . . + - + - . . . or . . . - + - + . . . gives 3v.

But my situation happened to have ended up with . . . + - - + . . . or . . . - + + - . . . gives Zero volts.

Same situation on the series connected voice coil and humbucking coil, except dealing with AC voltages and phase relationships.

That means that if the AF output transformer starts sending an audio signal thru the voice coil, that 120~ signal will pass
as far as the humbucking coil where there is then the presence of an out of phase ~120 cycle signal that has been picked up
from the field coil winding.

That will counteract with the output transformers ~120 cycle signal and both of the ~120 levels nullout and diminish appreciably. With all of the other audio spectum not being affected.

An economy effective procedure of the utilization of a mere few turns of wire, as compared to many, many microfarads
more of capacitance used for filtering of the power supply.

So, in the testing of your Peeeelco, the lifting of one of the AF output transformer leads to the speaker then should let you explore the presence of a low ohms path thru the voice coil winding and that series hum bucking coil.

If an open circuit is found there, consider the next test of going to the flexible leads at the side of the cone to see if there is an
open connection there from flex failure.

Also there is a possibility of the smaller wire connection , from that flexwire terminal / rivet on the cone that routes down the side of the cone to reach into the voice coil winding.

Pee Ess. .the erroneous cross ref info on the 5Y4 tooobie, was not from me.