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Old 11-27-2024, 03:00 PM
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init4fun init4fun is offline
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The wiring diagram that jr_tech was very helpful in providing states that the field coil is 460 ohms. It's highly likely that the voice coil / "humbucking" coil (in series) are FAR less than 460 ohms. Only 4 wires lead out of the speaker to the chassis......

Use your Ohmmeter and find the two wires with 460 Ohms across the two (or pretty damned near it) and connect those to the proper places indicated on the schematic (one to the # 80 rectifier's cathode and one to the audio output transformer's primary center tap).

The voice coil / humbucker wires (the two with MUCH lower resistance) will go to the output transformer's secondary.....

There, see, I did your homework for ya........ Your welcome

Last edited by init4fun; 11-27-2024 at 03:11 PM. Reason: clarify my point.....
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Old 11-28-2024, 12:02 AM
vortalexfan vortalexfan is offline
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Quote:
Originally Posted by init4fun View Post
The wiring diagram that jr_tech was very helpful in providing states that the field coil is 460 ohms. It's highly likely that the voice coil / "humbucking" coil (in series) are FAR less than 460 ohms. Only 4 wires lead out of the speaker to the chassis......

Use your Ohmmeter and find the two wires with 460 Ohms across the two (or pretty damned near it) and connect those to the proper places indicated on the schematic (one to the # 80 rectifier's cathode and one to the audio output transformer's primary center tap).

The voice coil / humbucker wires (the two with MUCH lower resistance) will go to the output transformer's secondary.....

There, see, I did your homework for ya........ Your welcome
I had seen part of the link that he had posted and I thought he was posting the link to the digital copy of the Riders version of the service data for this radio chassis which I already have a physical copy of which didn't provide any useful information as far as giving any voltage or resistance readings or any blowup diagrams of each individual speaker wire connection, that's why I responded the way I did, I wasn't trying to be mean or rude to him, I just thought that he was giving a link to something I already had a physical copy of which had proven to be useless already to me.

I apologize if my comment came off as being ungrateful or mean in anyway, it certainly wasn't my intention.

By the way, what is the source of that service data? It's definitely not Riders or Beitman's (which is basically the same info as in Rider's) because the service data in Rider's was not this detailed.

Last edited by vortalexfan; 11-28-2024 at 12:08 AM.
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Old 11-28-2024, 09:08 AM
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init4fun init4fun is offline
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Quote:
Originally Posted by vortalexfan View Post
I had seen part of the link that he had posted and I thought he was posting the link to the digital copy of the Riders version of the service data for this radio chassis which I already have a physical copy of which didn't provide any useful information as far as giving any voltage or resistance readings or any blowup diagrams of each individual speaker wire connection, that's why I responded the way I did, I wasn't trying to be mean or rude to him, I just thought that he was giving a link to something I already had a physical copy of which had proven to be useless already to me.

I apologize if my comment came off as being ungrateful or mean in anyway, it certainly wasn't my intention.

By the way, what is the source of that service data? It's definitely not Riders or Beitman's (which is basically the same info as in Rider's) because the service data in Rider's was not this detailed.
Not to worry, I wasn't bustin your balls, , , , much....

I believe that info came from Stewart Warner themselves, via "Nostalgia Air".

As long as you get the field coil connected to the B+ supply, and the voice coil to the output transformer's secondary, you won't fry anything. You now know from the schematic the field coil should be right around 460 ohms, I'd be surprised if the voice coil (with humbucking coil in series) would by much over about 16 to maybe 20 ohms, maybe even less. As long as you get similar readings the speaker is likely not fried. If, after hooking it up and installing new B+ filter caps* you have excessive hum, try reversing the voice coil's two leads going to the output transformer (swap the two wire's positions, one for each other) and see if the hum is reduced.

PS, both the field coil and voice coil should only have continuity across their two wires, and not have any continuity from their wires to the speaker's metal frame

* Both caps listed as part #39, which are 8 MFD at 435 volts rating. Use 10 MFD 450 volt modern electrolytics in their place. DO NOT drastically increase the MFD rating of them, if it played fine when new with 8 MFD, it surely will play just as fine now with 10 MFD. Drastically increasing the MFD rating will in no way be "better", and will in fact stress the rectifier and field coil (which is also the B+ filter choke) more than needed.

Last edited by init4fun; 11-28-2024 at 09:40 AM.
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