Hello All,
I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
If I do replace the speaker, how do I get it to fit where the original was?
Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.

Thanks,

Dave

This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).

Also, recheck all B+ levels.

Lou

:Hello All,
: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
: If I do replace the speaker, how do I get it to fit where the original was?
: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
:
:Thanks,
:
:Dave
:

Lou,
The voice coil is good but it cannot work if the field coil is open. So I'm not sure what a 9v battery is going to do if there's no magnetism to repel. But I'll try it.

Thanks,

Dave
:This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
:You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
:
:Also, recheck all B+ levels.
:
:Lou
:
:
::Hello All,
:: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
:: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
:: If I do replace the speaker, how do I get it to fit where the original was?
:: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
:: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
::
::Thanks,
::
::Dave
::
:

Lou,
B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
Otherwise it's ZERO volts.

Dave
:This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
:You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
:
:Also, recheck all B+ levels.
:
:Lou
:
:
::Hello All,
:: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
:: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
:: If I do replace the speaker, how do I get it to fit where the original was?
:: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
:: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
::
::Thanks,
::
::Dave
::
:

:Lou,
: B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
:Otherwise it's ZERO volts.
:
:Dave
::This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
::You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
::
::Also, recheck all B+ levels.
::
::Lou
::
::
:::Hello All,
::: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
::: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
::: If I do replace the speaker, how do I get it to fit where the original was?
::: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
::: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
:::
:::Thanks,
:::
:::Dave
:::
::
:
Terry

Terry,
It looks like the value that works is a 2.7 K ohms at 25 watts. Using another speaker sounds very very good. So the radio is working. For some reason when I have the new speaker across the old one, or if I don't connect another speaker, I can hear something from the old cone when the "field Coil resistor" is in the circuit. When I remove the resistor, of course there's no more B+.
I am in favor of using a filter choke as well. If you think it's at the very beginning of the winding, then I will take a look. I would rather skip the hot resistor. I have used a ceramic coffee cup to put such a resistor in, because it wouldn't fit inside the cabinet of the radio.
Thanks for the advice, and I will see if I can "repair" the field coil. Which end should I check? I guess both ends of the winding.

Thanks Again,

Dave
::Lou,
:: B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
::Otherwise it's ZERO volts.
::
::Dave
:::This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
:::You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
:::
:::Also, recheck all B+ levels.
:::
:::Lou
:::
:::
::::Hello All,
:::: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
:::: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
:::: If I do replace the speaker, how do I get it to fit where the original was?
:::: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
:::: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
::::
::::Thanks,
::::
::::Dave
::::
:::
::
:
:Dave- The open place in a field coil is usually at the very beginning of the winding. Start carefully removing the covering material and remove a few windings. The impedance, (actually inductance), of the coil is not critical and can be off by a lot. If you can't find it, and want to use a PM speaker, the secondary of a power transformer will work, or at least give you some idea of where to go from there. It's true that a resistor CAN be used successfully, but I always feel that is a cop out. The coil is an integral part of the filter circuit and is there for a reason. I always explore every other possibility before resorting to a resistor. Also, remember that not only the B+, but a LOT of current is passing through the coil. So don't forget to use Ohms law to calculate the wattage.
:Terry
:

Terry,
The ends of the coil seem very difficult to get to. Also that tape is very thick. I'll keep trying to get it off. Do I have to unbolt the speaker, the speaker transformer and then entire dial to do this? There must be an easier way. The sides of the speaker are welded to two metal posts.

Thanks,

Dave
:Terry,
: It looks like the value that works is a 2.7 K ohms at 25 watts. Using another speaker sounds very very good. So the radio is working. For some reason when I have the new speaker across the old one, or if I don't connect another speaker, I can hear something from the old cone when the "field Coil resistor" is in the circuit. When I remove the resistor, of course there's no more B+.
: I am in favor of using a filter choke as well. If you think it's at the very beginning of the winding, then I will take a look. I would rather skip the hot resistor. I have used a ceramic coffee cup to put such a resistor in, because it wouldn't fit inside the cabinet of the radio.
: Thanks for the advice, and I will see if I can "repair" the field coil. Which end should I check? I guess both ends of the winding.
:
:Thanks Again,
:
:Dave
:::Lou,
::: B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
:::Otherwise it's ZERO volts.
:::
:::Dave
::::This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
::::You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
::::
::::Also, recheck all B+ levels.
::::
::::Lou
::::
::::
:::::Hello All,
::::: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
::::: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
::::: If I do replace the speaker, how do I get it to fit where the original was?
::::: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
::::: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
:::::
:::::Thanks,
:::::
:::::Dave
:::::
::::
:::
::
::Dave- The open place in a field coil is usually at the very beginning of the winding. Start carefully removing the covering material and remove a few windings. The impedance, (actually inductance), of the coil is not critical and can be off by a lot. If you can't find it, and want to use a PM speaker, the secondary of a power transformer will work, or at least give you some idea of where to go from there. It's true that a resistor CAN be used successfully, but I always feel that is a cop out. The coil is an integral part of the filter circuit and is there for a reason. I always explore every other possibility before resorting to a resistor. Also, remember that not only the B+, but a LOT of current is passing through the coil. So don't forget to use Ohms law to calculate the wattage.
::Terry
::
:

Terry,
I got the tape off, and found the ends of the magnet wire (fine as a human hair). I used a lighter to get the enamel off near the end of the magnet wire, wrapped it around the lead wire, and soldered. I measure 165 ohms. I put the speaker back into the radio and it works. It doesn't sound quite as good as a modern speaker, but it's working and I don't need to add a large hot resistor.

Thanks Again,

Dave
::Lou,
:: B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
::Otherwise it's ZERO volts.
::
::Dave
:::This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
:::You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
:::
:::Also, recheck all B+ levels.
:::
:::Lou
:::
:::
::::Hello All,
:::: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
:::: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
:::: If I do replace the speaker, how do I get it to fit where the original was?
:::: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
:::: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
::::
::::Thanks,
::::
::::Dave
::::
:::
::
:
:Dave- The open place in a field coil is usually at the very beginning of the winding. Start carefully removing the covering material and remove a few windings. The impedance, (actually inductance), of the coil is not critical and can be off by a lot. If you can't find it, and want to use a PM speaker, the secondary of a power transformer will work, or at least give you some idea of where to go from there. It's true that a resistor CAN be used successfully, but I always feel that is a cop out. The coil is an integral part of the filter circuit and is there for a reason. I always explore every other possibility before resorting to a resistor. Also, remember that not only the B+, but a LOT of current is passing through the coil. So don't forget to use Ohms law to calculate the wattage.
:Terry
:

:Terry,
: I got the tape off, and found the ends of the magnet wire (fine as a human hair). I used a lighter to get the enamel off near the end of the magnet wire, wrapped it around the lead wire, and soldered. I measure 165 ohms. I put the speaker back into the radio and it works. It doesn't sound quite as good as a modern speaker, but it's working and I don't need to add a large hot resistor.
:
:Thanks Again,
:
:Dave

No problem. I'm just glad it helped. I forgot where I got that hint, but it works on most transformers, including power, audio and IF. If you think about it it makes sense. The open part usually isn't in the middle but the incoming lead.
Terry
:::Lou,
::: B+ is 195 volts only if I replace the field coil with a 3K ohm resistor.
:::Otherwise it's ZERO volts.
:::
:::Dave
::::This may seem silly but you should take a 9 v battery and tap the voice coil on the speaker. It may be open.
::::You should hear some weak clicks with any residual magnetism for the coil to work over ( I would think).
::::
::::Also, recheck all B+ levels.
::::
::::Lou
::::
::::
:::::Hello All,
::::: I don't see anywhere in the service data a resistance value for the field coil. It seems to be open. However when I use a 3 K ohm resistor in place of it, I still get no sound from the speaker transformer (connected to another speaker), and that's not open. I think that the voltages are a little low with the 3 k ohm resistor. Should it be more like 1.5 K or 2 K?
::::: The 6B5 could also be defective but I still think the voltages are a little too low for it to work. All paper and electrolytic capacitors have been replaced (all 13 of them).
::::: If I do replace the speaker, how do I get it to fit where the original was?
::::: Also one of the resistors in the voltage divider resistor on the back was open and someone substituted a 15K ohm resistor for the 25K ohm section. So that could be messing up the voltages as well.
::::: I'll let you know what I find. Someone replaced the 16 mfd capacitor with a .22 mfd capacitor, and someone added a 2 mfd capacitor between one end of the 8K ohm section of the voltage divider resistor and the chassis. What a mess! The leaky 16 mfd capacitor was still connected. Nobody ever replaced any of the paper capacitors, and it was sold to someone, not me, as a "restored" radio. I see this a lot. But the condition of the capacitors and continuing to use it that way probably led to the damage to the field coil in the speaker.
:::::
:::::Thanks,
:::::
:::::Dave
:::::
::::
:::
::
::Dave- The open place in a field coil is usually at the very beginning of the winding. Start carefully removing the covering material and remove a few windings. The impedance, (actually inductance), of the coil is not critical and can be off by a lot. If you can't find it, and want to use a PM speaker, the secondary of a power transformer will work, or at least give you some idea of where to go from there. It's true that a resistor CAN be used successfully, but I always feel that is a cop out. The coil is an integral part of the filter circuit and is there for a reason. I always explore every other possibility before resorting to a resistor. Also, remember that not only the B+, but a LOT of current is passing through the coil. So don't forget to use Ohms law to calculate the wattage.
::Terry
::
:

Can also test audio transformer with original speaker even if no field coil operation. touch the battery to the primary winding of the audio output transformer. I click should be heard.