Hi Folks,

No I am not watching the game. I am working on my radios today. :-)
http://www.nostalgiaair.org/Resources/091/M0025091.htm

I just finished a complete re-wiring (plastic wire insulation was crumbling)and re-capping of the subject radio. I was very methodical in replacing the wires. I did it one by one to insure I had the right connections. The electrolytics and paper caps were all replaced. I haven't replaced the Mica caps. I haven't replaced resistors as the ones tested in the power section were fine.
The radio isn't picking up any stations. I do get a barely discernable hum if I put my ear right up to the speaker. Started checking tube voltages and found low readings at 35L6G pin 3 (plate) should be 79 vdc and is at 16. Other pins in the set that should be at 85 to 85.5 to 86 VDC are all very low near 16VDC. Most of these are tube plates. Output of rectifier tube is a little under the 117V, at around 80/90vdc.

I do have a list of all volt measurements for all tubes if needed.

Filament voltage looks pretty good but that is AC.
Any ideas on what to look for? What could be affecting voltage on tubes 12SA7G, 12K7GT, 14H7 and 35L6G. All tubes have been thoroughly tested including check for shorts.

I also need to know what type of dial lamp is right for this radio. It is bayonet, and appears to be 120V?. It says 10 on the schematic. I am used to low voltage lamps. The original lamp was missing.

Happy Super Bowl!

Kindest Regards,
Jeff

Update: I checked the speaker coils and they are within specification for resistance at 220 and 485 Ohms. I was thinking there might be a short...and am happy that doesn't seem to be the case.

:Hi Folks,
:
:No I am not watching the game. I am working on my radios today. :-)
:http://www.nostalgiaair.org/Resources/091/M0025091.htm
:
:I just finished a complete re-wiring (plastic wire insulation was crumbling)and re-capping of the subject radio. I was very methodical in replacing the wires. I did it one by one to insure I had the right connections. The electrolytics and paper caps were all replaced. I haven't replaced the Mica caps. I haven't replaced resistors as the ones tested in the power section were fine.
:The radio isn't picking up any stations. I do get a barely discernable hum if I put my ear right up to the speaker. Started checking tube voltages and found low readings at 35L6G pin 3 (plate) should be 79 vdc and is at 16. Other pins in the set that should be at 85 to 85.5 to 86 VDC are all very low near 16VDC. Most of these are tube plates. Output of rectifier tube is a little under the 117V, at around 80/90vdc.
:
:I do have a list of all volt measurements for all tubes if needed.
:
:Filament voltage looks pretty good but that is AC.
:Any ideas on what to look for? What could be affecting voltage on tubes 12SA7G, 12K7GT, 14H7 and 35L6G. All tubes have been thoroughly tested including check for shorts.
:
:I also need to know what type of dial lamp is right for this radio. It is bayonet, and appears to be 120V?. It says 10 on the schematic. I am used to low voltage lamps. The original lamp was missing.
:
:Happy Super Bowl!
:
:Kindest Regards,
:Jeff

So you answer the easy questions 1st? :-)

:Update: I checked the speaker coils and they are within specification for resistance at 220 and 485 Ohms. I was thinking there might be a short...and am happy that doesn't seem to be the case.
:
::Hi Folks,
::
::No I am not watching the game. I am working on my radios today. :-)
::http://www.nostalgiaair.org/Resources/091/M0025091.htm
::
::I just finished a complete re-wiring (plastic wire insulation was crumbling)and re-capping of the subject radio. I was very methodical in replacing the wires. I did it one by one to insure I had the right connections. The electrolytics and paper caps were all replaced. I haven't replaced the Mica caps. I haven't replaced resistors as the ones tested in the power section were fine.
::The radio isn't picking up any stations. I do get a barely discernable hum if I put my ear right up to the speaker. Started checking tube voltages and found low readings at 35L6G pin 3 (plate) should be 79 vdc and is at 16. Other pins in the set that should be at 85 to 85.5 to 86 VDC are all very low near 16VDC. Most of these are tube plates. Output of rectifier tube is a little under the 117V, at around 80/90vdc.
::
::I do have a list of all volt measurements for all tubes if needed.
::
::Filament voltage looks pretty good but that is AC.
::Any ideas on what to look for? What could be affecting voltage on tubes 12SA7G, 12K7GT, 14H7 and 35L6G. All tubes have been thoroughly tested including check for shorts.
::
::I also need to know what type of dial lamp is right for this radio. It is bayonet, and appears to be 120V?. It says 10 on the schematic. I am used to low voltage lamps. The original lamp was missing.
::
::Happy Super Bowl!
::
::Kindest Regards,
::Jeff

1st:
Was the radio working before you started re-wire?

2.) If it was... then perhaps you've just mis wired something.
The B+ is low... ok..
There should be AC (120v) on the plate
You should measure 120 DC or higher on the Cathode

So first check that the electrolytics are correctly polarized.
Then if so..
Measure 120 v AC on the PLATE of the 35Z5
Then..
Remove all loads by removing the wire from the 35Z5 CATHODE. Then it should measure about 120 VDC.

If it does not perhaps that rectifier is bad or mis wired.

If the cathode DOES have 120vDC or higher...good.

Then replace the wire to the Cathode.

Then remove the B+ leads to the rest of the radio from C12. Just leave the field coil lead to C12.
Then turn on radio and measure voltage at C12.

If good... then you have a short or excess load in the B+ load circuit...
If you still have low voltage on C12... then the problem is in the power supply.
Measure the B+ on C13... if that is good... then perhaps the field coil is open or not wired properly.

:1st:
:Was the radio working before you started re-wire?
:
:2.) If it was... then perhaps you've just mis wired something.
:The B+ is low... ok..
:There should be AC (120v) on the plate
:You should measure 120 DC or higher on the Cathode
:
:So first check that the electrolytics are correctly polarized.
:Then if so..
:Measure 120 v AC on the PLATE of the 35Z5
:Then..
:Remove all loads by removing the wire from the 35Z5 CATHODE. Then it should measure about 120 VDC.
:
:If it does not perhaps that rectifier is bad or mis wired.
:
:If the cathode DOES have 120vDC or higher...good.
:
:Then replace the wire to the Cathode.
:
:Then remove the B+ leads to the rest of the radio from C12. Just leave the field coil lead to C12.
:Then turn on radio and measure voltage at C12.
:
:If good... then you have a short or excess load in the B+ load circuit...
:If you still have low voltage on C12... then the problem is in the power supply.
:Measure the B+ on C13... if that is good... then perhaps the field coil is open or not wired properly.

I would expect the bulb to be a #47.
Lewis

:1st:
:Was the radio working before you started re-wire?
:
:2.) If it was... then perhaps you've just mis wired something.
:The B+ is low... ok..
:There should be AC (120v) on the plate
:You should measure 120 DC or higher on the Cathode
:
:So first check that the electrolytics are correctly polarized.
:Then if so..
:Measure 120 v AC on the PLATE of the 35Z5
:Then..
:Remove all loads by removing the wire from the 35Z5 CATHODE. Then it should measure about 120 VDC.
:
:If it does not perhaps that rectifier is bad or mis wired.
:
:If the cathode DOES have 120vDC or higher...good.
:
:Then replace the wire to the Cathode.
:
:Then remove the B+ leads to the rest of the radio from C12. Just leave the field coil lead to C12.
:Then turn on radio and measure voltage at C12.
:
:If good... then you have a short or excess load in the B+ load circuit...
:If you still have low voltage on C12... then the problem is in the power supply.
:Measure the B+ on C13... if that is good... then perhaps the field coil is open or not wired properly.

I would expect the bulb to be a #47.
Lewis

:1st:
:Was the radio working before you started re-wire?
:
:2.) If it was... then perhaps you've just mis wired something.
:The B+ is low... ok..
:There should be AC (120v) on the plate
:You should measure 120 DC or higher on the Cathode
:
:So first check that the electrolytics are correctly polarized.
:Then if so..
:Measure 120 v AC on the PLATE of the 35Z5
:Then..
:Remove all loads by removing the wire from the 35Z5 CATHODE. Then it should measure about 120 VDC.
:
:If it does not perhaps that rectifier is bad or mis wired.
:
:If the cathode DOES have 120vDC or higher...good.
:
:Then replace the wire to the Cathode.
:
:Then remove the B+ leads to the rest of the radio from C12. Just leave the field coil lead to C12.
:Then turn on radio and measure voltage at C12.
:
:If good... then you have a short or excess load in the B+ load circuit...
:If you still have low voltage on C12... then the problem is in the power supply.
:Measure the B+ on C13... if that is good... then perhaps the field coil is open or not wired properly.

I would expect the bulb to be a #47.
Lewis

Hi Lewis,
I found a bayonet lamp rated for 130V and ordered it. You can see on the schematic that it picks up from the AC side of the 35L6 at or near full line voltage. Thanks!

::1st:
::Was the radio working before you started re-wire?
::
::2.) If it was... then perhaps you've just mis wired something.
::The B+ is low... ok..
::There should be AC (120v) on the plate
::You should measure 120 DC or higher on the Cathode
::
::So first check that the electrolytics are correctly polarized.
::Then if so..
::Measure 120 v AC on the PLATE of the 35Z5
::Then..
::Remove all loads by removing the wire from the 35Z5 CATHODE. Then it should measure about 120 VDC.
::
::If it does not perhaps that rectifier is bad or mis wired.
::
::If the cathode DOES have 120vDC or higher...good.
::
::Then replace the wire to the Cathode.
::
::Then remove the B+ leads to the rest of the radio from C12. Just leave the field coil lead to C12.
::Then turn on radio and measure voltage at C12.
::
::If good... then you have a short or excess load in the B+ load circuit...
::If you still have low voltage on C12... then the problem is in the power supply.
::Measure the B+ on C13... if that is good... then perhaps the field coil is open or not wired properly.
:
:
:
:
:
:
:I would expect the bulb to be a #47.
:Lewis

1. I do not know if it was working before rewiring as the condition of the wires was unsafe. I didn't try it.
2. While possibe I miswired, I doubt it. I have rewired many radios. I replaced one wire at a time. It is possible it had a problem when I acquired it. However, if i find I did miswire I will purchase new reading glasses. :-)
Thanks for the suggestions, that is exactly what I was looing for. I have had my nose in this radio for far too long and couldn't see the forest for the trees. I will try this tonight.

Hi Folks,
:
:No I am not watching the game. I am working on my radios today. :-)
:http://www.nostalgiaair.org/Resources/091/M0025091.htm
:
:I just finished a complete re-wiring (plastic wire insulation was crumbling)and re-capping of the subject radio. I was very methodical in replacing the wires. I did it one by one to insure I had the right connections. The electrolytics and paper caps were all replaced. I haven't replaced the Mica caps. I haven't replaced resistors as the ones tested in the power section were fine.
:The radio isn't picking up any stations. I do get a barely discernable hum if I put my ear right up to the speaker. Started checking tube voltages and found low readings at 35L6G pin 3 (plate) should be 79 vdc and is at 16. Other pins in the set that should be at 85 to 85.5 to 86 VDC are all very low near 16VDC. Most of these are tube plates. Output of rectifier tube is a little under the 117V, at around 80/90vdc.
:
:I do have a list of all volt measurements for all tubes if needed.
:
:Filament voltage looks pretty good but that is AC.
:Any ideas on what to look for? What could be affecting voltage on tubes 12SA7G, 12K7GT, 14H7 and 35L6G. All tubes have been thoroughly tested including check for shorts.
:
:I also need to know what type of dial lamp is right for this radio. It is bayonet, and appears to be 120V?. It says 10 on the schematic. I am used to low voltage lamps. The original lamp was missing.
:
:Happy Super Bowl!
:
:Kindest Regards,
:Jeff

:Ah, Merci Mon Ami
:Oui d'accord.
::“You can see on the schematic that it picks up from the AC side of the 35L6 at or near full line voltage”
:
:
:
:
:Au contraire, mon sieur ….for certain that you ARE seeing the left connection of the ,lamp and referencing it to the full line voltage, BUT, its right connection is shunting across the low resistance of a portion of the 35Z5 rectifier tube, so therefore it would be more in the order of the mentioned #47 lamp and its ~6-8V @ 150 ma spec. That decreased voltage passage without a lamp in circuit could also account for a little degree your B+ malfunction.
:
:73's de Edd
:
:
:
:
:
:
:
:
::1. I do not know if it was working before rewiring as the condition of the wires was unsafe. I didn't try it.
::2. While possibe I miswired, I doubt it. I have rewired many radios. I replaced one wire at a time. It is possible it had a problem when I acquired it. However, if i find I did miswire I will purchase new reading glasses. :-)
::Thanks for the suggestions, that is exactly what I was looing for. I have had my nose in this radio for far too long and couldn't see the forest for the trees. I will try this tonight.
::
::Hi Folks,
:::
:::No I am not watching the game. I am working on my radios today. :-)
:::http://www.nostalgiaair.org/Resources/091/M0025091.htm
:::
:::I just finished a complete re-wiring (plastic wire insulation was crumbling)and re-capping of the subject radio. I was very methodical in replacing the wires. I did it one by one to insure I had the right connections. The electrolytics and paper caps were all replaced. I haven't replaced the Mica caps. I haven't replaced resistors as the ones tested in the power section were fine.
:::The radio isn't picking up any stations. I do get a barely discernable hum if I put my ear right up to the speaker. Started checking tube voltages and found low readings at 35L6G pin 3 (plate) should be 79 vdc and is at 16. Other pins in the set that should be at 85 to 85.5 to 86 VDC are all very low near 16VDC. Most of these are tube plates. Output of rectifier tube is a little under the 117V, at around 80/90vdc.
:::
:::I do have a list of all volt measurements for all tubes if needed.
:::
:::Filament voltage looks pretty good but that is AC.
:::Any ideas on what to look for? What could be affecting voltage on tubes 12SA7G, 12K7GT, 14H7 and 35L6G. All tubes have been thoroughly tested including check for shorts.
:::
:::I also need to know what type of dial lamp is right for this radio. It is bayonet, and appears to be 120V?. It says 10 on the schematic. I am used to low voltage lamps. The original lamp was missing.
:::
:::Happy Super Bowl!
:::
:::Kindest Regards,
:::Jeff