Speaker replacement on a 1941 Philco Tropic 41-705

In this video I replace a damaged speaker with an electrodynamic coil which is part of the power supply, I replace it with a permanent magnet speaker and show how to replace the electrodynamic coil with a power resistor of similar resistance.

[@justsumguy2u]

An alternate trick I like to use is to separate the field coil from the rest of the speaker, and mount it somewhere on the chassis or cabinet; that way it stays in-circuit, and the power supply operates the same as before

[@FranksPlace-jk7pj]

That's a good idea, but I'm hoping to maybe repair the speaker in the future.

[@hestheMaster]

This is the kind of radio with a special ballast tube. Philco number 33-3389. It was put
into a special octal socket with two keyways, one for 115 V and the other for 230 V. I
see the wiring diagram for the ballast tube on the schematic and looking at it is actually only used as a jumper for the connections for 125 Volts. It is needed for 230V when you
place it in the right position for that voltage. If you have the ballast tube and it is dead
check the ordinary wire connections in the base for continuity. Pins 2,3, and 7. Then you
can redo the speaker next. But not this way, yikes. Rotten insulation on many wires to
be replaced. And don't modify the chassis to fit a too large PM speaker!

[@FranksPlace-jk7pj]

My hope is to repair the speaker cone and put it back in the radio, as everything on the speaker assembly is good except the paper cone.

[@jimburns348]

Hacker