Hello--

I recently undertook the restoration of a Delco 3205 radio which had been scabbed together with another unidentified radio. As such parts were missing and the wiring didn't follow the diagram. After much soldering I have run into difficulties. As this is my first experience with a tube radio, I am confused with what to replace the two IF transformers with. I have two (what I think) are IF transformers from the radio it was scabbed onto, but don't know if they are interchangeable. Furthermore, the AF transformer is missing, and the diagram has no mention of a rating or part number. To make matters even more difficult I am missing a third transformer (iron core) on the diagram, BUT, the diagram has no part listing for it, so I really have no idea what function this transformer serves. Looking at the wiring diagram it seems to be connected to the speaker. I am working from diagram 7-31 in the United Motors Service manual.

Any help would be appreciated.

Eric

Hello Eric.

Pleasure in you help him. I am in Brazil and I saw its report.
For the that I understood, you have two the same radios, but there is not reason to mutilate anyone of them in favor of the another.
Do you have a multimeter?
If you have, make the following. Meça cada coil duvidoso. The enrolamentos of FI´s should give something around the 16 Ohms, each one.
The Transformer of AF, he/she should give in the primary, in each one of the coils, since it is a push-pull, something around the 150 Ohms. The Secondary of that transformer, it should be of 4 Ohms.
Me not very I believe that the fi transformers, be with problem.
Do tell the experiences and if it cannot, do order me a photo of the radio, ok?
Thank you.
Indalécio.

officinadoradio@gmail.com

:Hello Eric.
:
:Pleasure in you help him. I am in Brazil and I saw its report.
:For the that I understood, you have two the same radios, but there is not reason to mutilate anyone of them in favor of the another.
:Do you have a multimeter?
:If you have, make the following. Meça cada coil duvidoso. The enrolamentos of FI´s should give something around the 16 Ohms, each one.
:The Transformer of AF, he/she should give in the primary, in each one of the coils, since it is a push-pull, something around the 150 Ohms. The Secondary of that transformer, it should be of 4 Ohms.
:Me not very I believe that the fi transformers, be with problem.
:Do tell the experiences and if it cannot, do order me a photo of the radio, ok?
:Thank you.
:Indalécio.
:
:officinadoradio@gmail.com

Yes, I have another radio chassis, however the other radio is not a Delco 3205, I have no idea what make that radio is. I am assuming my radio, since it didn't have IF transformers, was using the IFs from the other chassis. Are all IF transformers the same rating? The Delco 3205, has no AF transformer, and I'm not sure what size to put in. The wiring diagram makes no mention of size either. Any way a person could look at the diagram and make a guess?

Thanks-
Eric

::Hello Eric.
::
::Pleasure in you help him. I am in Brazil and I saw its report.
::For the that I understood, you have two the same radios, but there is not reason to mutilate anyone of them in favor of the another.
::Do you have a multimeter?
::If you have, make the following. Meça cada coil duvidoso. The enrolamentos of FI´s should give something around the 16 Ohms, each one.
::The Transformer of AF, he/she should give in the primary, in each one of the coils, since it is a push-pull, something around the 150 Ohms. The Secondary of that transformer, it should be of 4 Ohms.
::Me not very I believe that the fi transformers, be with problem.
::Do tell the experiences and if it cannot, do order me a photo of the radio, ok?
::Thank you.
::Indalécio.
::
::officinadoradio@gmail.com

Hello Eric.
Excuse the delay, it happens that my personal computer was invaded... The Transformer of AF that I recommend you, has to have at least 6Watts. Order in my email a photo of the radio, or of the chassis. It will be for me, easier.
Does some other one doubt?
Indalécio
:::officinadoradio@gmail.com

Here is the page with the wiring diagram: http://www.nostalgiaair.org/Resources/385/M0022385.htm

Also, where could I get an electrodynamic speaker, or how would I go about replacing the electrodynamic speaker with a permanent magnet?

Hello Eric.
:Excuse the delay, it happens that my personal computer was invaded... The Transformer of AF that I recommend you, has to have at least 6Watts. Order in my email a photo of the radio, or of the chassis. It will be for me, easier.
:Does some other one doubt?
:Indalécio
::::officinadoradio@gmail.com

:Here is the page with the wiring diagram: http://www.nostalgiaair.org/Resources/385/M0022385.htm
:
:Also, where could I get an electrodynamic speaker, or how would I go about replacing the electrodynamic speaker with a permanent magnet?
:
:Hello Eric.
::Excuse the delay, it happens that my personal computer was invaded... The Transformer of AF that I recommend you, has to have at least 6Watts. Order in my email a photo of the radio, or of the chassis. It will be for me, easier.
::Does some other one doubt?
::Indalécio
:::::officinadoradio@gmail.com

Hi Eric,

Congratulations on your radio find. This radio is one that was used on a 32 volt DC "Delco" system. I have seen one complete system and that was over 30 years ago. This system had once been installed in a house wired with 32 volt light bulbs. It had a 32 volt smoothing iron (clothes iron), a fan, a water well pump and a 32 volt DC radio. It had other electrical items which I can't remember.

I don't think adding a PM speaker will be that much of a problem. As for the speaker field, it is hooked across the 32 volt input so shouldn't have to worry about it. As for the output transformer you will have to look up the 48 tube in a tube charasterics manual to find the plate impedance and select an appropriate replacement (a universal replacement will probably work)output transformer. Have you checked inside of the IF transformers to see if they can be repaired? Sometimes the fine wire to the coils have corroded or broken loose from the solder connections. You could possibly build a 32 volt power supply to operate the radio or use batteries. Hopefully others on this site will jump in with some suggestions.

Radiodoc

Thanks for the response. This radio came from a ranch that used to have a 32v power plant that was charged from a windmill.

As for IF transformers, they are both still intact, but they are from the other radio that the Delco 3205 was wired into. Will the transformers from the other radio work? I assume that the Delco was using that part of the other radio.

If you look at the diagram, above the speaker symbol there is an iron core transformer that isn't given a part number. What is that? Is it a filter choke?

Thanks again-

Eric

:Hi Eric,
:
:Congratulations on your radio find. This radio is one that was used on a 32 volt DC "Delco" system. I have seen one complete system and that was over 30 years ago. This system had once been installed in a house wired with 32 volt light bulbs. It had a 32 volt smoothing iron (clothes iron), a fan, a water well pump and a 32 volt DC radio. It had other electrical items which I can't remember.
:
:I don't think adding a PM speaker will be that much of a problem. As for the speaker field, it is hooked across the 32 volt input so shouldn't have to worry about it. As for the output transformer you will have to look up the 48 tube in a tube charasterics manual to find the plate impedance and select an appropriate replacement (a universal replacement will probably work)output transformer. Have you checked inside of the IF transformers to see if they can be repaired? Sometimes the fine wire to the coils have corroded or broken loose from the solder connections. You could possibly build a 32 volt power supply to operate the radio or use batteries. Hopefully others on this site will jump in with some suggestions.
:
:Radiodoc
:

Eric,

I suppose if the IF transformers you mention were wired into the 3205 that they probably worked at one time (or maybe not). If I am looking at the same transformer you mention, that would be the audio output transformer (green and brown wires coming from it). The other transformer marked 31 on the diagram is a coupling/interstage transformer. It couples the signal from the plate (p) of the 85 to the grids of the 48 tubes. Since the output transformer isn't given a number, it may have been part of (mounted on) the speaker assembly.

Radiodoc

:Thanks for the response. This radio came from a ranch that used to have a 32v power plant that was charged from a windmill.
:
:As for IF transformers, they are both still intact, but they are from the other radio that the Delco 3205 was wired into. Will the transformers from the other radio work? I assume that the Delco was using that part of the other radio.
:
:If you look at the diagram, above the speaker symbol there is an iron core transformer that isn't given a part number. What is that? Is it a filter choke?
:
:Thanks again-
:
:Eric
:
::Hi Eric,
::
::Congratulations on your radio find. This radio is one that was used on a 32 volt DC "Delco" system. I have seen one complete system and that was over 30 years ago. This system had once been installed in a house wired with 32 volt light bulbs. It had a 32 volt smoothing iron (clothes iron), a fan, a water well pump and a 32 volt DC radio. It had other electrical items which I can't remember.
::
::I don't think adding a PM speaker will be that much of a problem. As for the speaker field, it is hooked across the 32 volt input so shouldn't have to worry about it. As for the output transformer you will have to look up the 48 tube in a tube charasterics manual to find the plate impedance and select an appropriate replacement (a universal replacement will probably work)output transformer. Have you checked inside of the IF transformers to see if they can be repaired? Sometimes the fine wire to the coils have corroded or broken loose from the solder connections. You could possibly build a 32 volt power supply to operate the radio or use batteries. Hopefully others on this site will jump in with some suggestions.
::
::Radiodoc
::