[klondike98]

I’ve started looking at the Stewart Warner model 415 speaker. (It could also be a 425 which looks the same on the exterior but came out a year later in 1927.) I previously had the backside off of it and today was able to get the front off.
[Image: https://www.dropbox.com/s/41r4kom1enh9yd....jpg?raw=1]
[Image: https://www.dropbox.com/s/51rvq8yfgnwifu....jpg?raw=1]
[Image: https://www.dropbox.com/scl/fi/v46s7qw23...n9og&raw=1]

The magnet and coils are connected in ways I have yet to sort out. The speaker cone center is connected with a small rod to two other rods that connect into the coil/magnet assembly. I could not get a good picture of it but Sonny at radiolaguy.com has some great images. Scroll down and see the “original drive” image. If I unscrew the two big screws on the bottom of the assembly it does come loose but remains connected to the speaker coil via the rods you see in Sonny’s photo, so I can’t just remove it. It appears I would have to remove the entire cone to access the the coil assembly. One or both of the coils are open.

[Image: https://www.dropbox.com/scl/fi/v46s7qw23...n9og&raw=1]

The main body of speaker seems to be brass (at least it is non-magnetic) although the rims that hold the grill cloth and “dancing ladies” are steel. Unfortunately with this set some of that steel has rusted badly and I suspect when I remove the rust it will be very thin, pitted and deformed. I’ll have to think about how to fix that, perhaps some car body epoxy. I don’t have the capability to weld but could solder in some metal if needed also. That’s for later.

[klondike98]

I was able to figure out how the speaker cone and driver/coil assembly went into the speaker and remove it from the speaker frame. The cone was held in place by several strips of felt behind, on the side edge and infront of the cone and finally a metal rim screwed in place to hold it all firm. Thus when I removed the screws holding the driver/coil assembly to the frame, the cone and driver all came out together.

[Image: https://www.dropbox.com/scl/fi/mwd5epicd...fz8y&raw=1]

[Image: https://www.dropbox.com/scl/fi/62vv5lp1s...i260&raw=1]

[Image: https://www.dropbox.com/scl/fi/rdeq6x1ej...innu&raw=1]

[Image: https://www.dropbox.com/scl/fi/h32a9as92...tkxs&raw=1]

This allowed me access to some of the connections for the wires in the coils. At first I thought I was going to get lucky and solve the coil continuity problem with a simple reflow of solder around the main speaker lead connections on the top of the driver assembly. It did solve one connection issue but there are others. You can actually get an ohm meter lead onto the wire just as it enters and leaves the coil as well as at a point midway through each coil and after checking all the various combinations to try and figure out where there might be a wire break, I find that there is a problem in all sections of the coils. Unfortunately, the dirver assembly appears to be a press fit together in multiple places. They probably originally had a jig of some type to place the various parts in and then pressed the driver frame together. I do not believe I can get it appart and successfully back together again so I've decided not to try. My next decision is whether I put it back together or fit it with a 1930s PM speaker with an audio transformer mounted someplace. (this is what Sonny, the radiolaguy, did with his, see: https://www.radiolaguy.com/Images/coneSp...425-Ri.jpg)

[klondike98]

I finally got back to this speaker and elected not to fit it with a newer driver and cone. I also elected not to remove the wire mesh that holds the speaker cloth in place. The cloth is discolored and dirty but I felt that a) I might easily damage the mesh in ways that kept it from going back into the frame correctly and would thus look bad and b) a more original look just felt like the right thing to do. So the entire unit got a cleaning with a mild detergent, the base got a bit more rigorous cleaning to get some of the corrosion off and then the dancing ladies got a paste wax coating to provide a bit of protection and a little luster. While the ladies are brass I did not polish off the patina which was original to the piece.

[Image: https://www.dropbox.com/scl/fi/t0mxosls1...hxcv&raw=1]