Hello everyone,

This is a repost after I saw what happened at the end of the last one.

The old speaker has three terminal connections, one from the field coil and two from the copper coil in the speaker coil.

I cannot figure out how to wire in another speaker that only has two wire connections. Help on this?

The field coil and speaker coil are good, the speaker is shot.

If I opt to go with the resistor work around how would I do it with this set up?

Is there a web site that explains how to do the work around?

Thank you,

Mitch

If you notice by the schematic, the secondary of the audio output transformer is at chassis ground. This would have been the 4th wire. Only one wire to the voice coil. The field coil must have two wires. You would use a resistor that would match the resistance of the original field coil. I would select wattage value by the amount of current draw though the resistor.

:If you notice by the schematic, the secondary of the audio output transformer is at chassis ground. This would have been the 4th wire. Only one wire to the voice coil. The field coil must have two wires. You would use a resistor that would match the resistance of the original field coil. I would select wattage value by the amount of current draw though the resistor.
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Thanks Warren,

It has taken some time for me to figure this all out, I only have limited time to work on my radios due to a recovery time from an illness.

This is an FYI for the first time solutions for those who have not had this issue to deal with.

Start, just a real bad torn up speaker. Radio has a field coil and audio transformer, speaker cone is 85% missing.

Clip in a PM speaker, sounds great!

The cabinet is too small to just install a new PM speaker, nothing will fit. The audio coil and speaker are assembled like a tank.

Remove speaker assembly and find a used coil along with a used PM speaker that you can make a fit with.

So, the field coil is good, thank the radio god's.

Found a small audio coil from the junk box and a used PM speaker that will both fit in the space where the old assembly came out, modifications that we are used to making.

I was not sure how to wire this Mod, too many meds-foggy mind. Warren drew it in with the ground, missing 4th wire.

The two green wires go to the PRI of the audio transformer from the radio audio output circuit.

Yellow wire from the SEC goes to chassis ground. (4th wire)

White wire from SEC to PM connection and other white wire from Field Coil to PM connection.

The speaker output is just fine.

Now to install the separate audio transformer and speaker in the gaping hole left by the old tank assembly.

Comments welcome, info to help others.

Mitch

The original field coil also has a hum bucking coil. On the schematic shown as BC connected to speaker. You will have to add a resistor in place of the field coil. Measure the field coil resistance then pick a resistor around the same value. The wattage Depends on current draw. Start out with a 5 watt resistor for test.