Hey y'all, new here, but not to radios. I posted this question to a FB antique radio group, but got scant help, but maybe there'll be better luck here. This is for a serious restoration for a client.
At some point someone tried working on this thing, but buggered numerous things. The oscillator coil (32-2120) is missing entirely, so I need to source another one, or find turns\wire gauge data and make my own.
Speaker is missing both the cone and the voice coil. The speaker that was in the cabinet also doesn't match the part number for this radio model. It has a 32-9118, but it should be 36-1225. If anyone's got a source for a new speaker or just cone and voice coil for this (incorrect?) speaker, I'm all ears.
Appreciate it!
Since the original inquiry isn't gaining much traction, does anybody know what the impedance is for the voice coil of the original speaker for this model, or models that use roughly the same speaker? The schematics that I have don't show that specification. Part of me wants to default to 8 ohms, but I want to make sure. At this point I'm likely just to remove the field coil and output transformer leave them in circuit, and find a permanent magnet speaker with the same dimensions and impedance.
On the oscillator coil, is there a similar model that uses a similar coil with known specs? Any ideas there? The resistance readings shown in the schematic indicate that the RF coil has rather close resistance readings, so I may have to unwind the RF coil, which also needs work anyway, and use that to get a ballpark idea on rewinding a new oscillator coil, if I can find a bobbin.
Your speaker is a K-7 and can be found on pg 4 here.
https://philcoradio.com/library/index.ph.../speakers/
If it was mine I would send it to Rich over @ Sound Remedy. Does great work and prices are reasonable.
As for the osc coil I don't know of any published specs for the # of turns or inductance. You are probably looking at finding a replacement or doing some trial and error to get something that will work.
you could put an add in the wanted ads for the osc coil and speaker if you don't have it repaired.
The original speaker used was
S-16 per the "Philco Speakers" file available
here on this website (which Terry also linked to in post #3 above). Remember, the radio being discussed is a
37-89B, not an 89B which is a very different animal.
Anyway, the S-16 speaker has an 1140 ohm field coil, and appears to be the same as the
S-7 speaker which would be easier to find since it was used in several models between 1933 and 1938.
Regarding the oscillator coil, you are likely stuck with either finding one from a junk 37-89 or 38-89 set, or using one of those "universal" oscillator coils such as
this one from Antique Electronic Supply. The problem is, if you go that route, you will only have an AM radio and your band 2 will be dead.
Winding data was never published by the manufacturer.
37-89 and 38-89 sets come up for sale fairly frequently on the auction site, including just chassis. Be careful and don't pay too much, though. A fair price for a parts chassis for one of these is around $20 to $50. Those who ask $100 or more are living in Fantasyland.
That's kind of what I expected as far as the oscillator coil goes - I figured it might be a shot in the dark for technical info. I was already eyeballing the universal coil on AES. I might suggest to the client that the other band selection be changed to aux in, and get that universal oscillator coil just for AM.
On the speaker, hearing that it has the same specifications as a more common speaker from the same era, really helps. That opens up a lot more options.
I may still put in a want-ad in that section of the forum, though.
Thanks!