I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
Don Black.
:I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
Don Black.

:Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
:each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
:Don Black.

::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

:Yes, I do have a schematic, norm gave me one. Replaced tubes already to see if hum goes away..no luck. C14?..looks like its across the main line. Which way does the cap go +/-, or does it matter? I thought you couldnt put a cap across the wall a/c, wouldnt it go poof, maximum smoke. Or is the value small enough not to burn up? Isnt the chassis the ground on this set?
:
:I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
:Don Black.
:
::Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
::each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
::Don Black.
:
:::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

Hi Sean, That capacitor across the mains is small enough to not draw too much current. Actually, it's a bit large by today's standards, probably about 0.047µf would be a better choice but it's not critical. The set will work without it but might pick up some interference that the capacitor will block. It's a non polarized capacitor so it doesn't matter which way it's connected. If possible get one of the capacitors designed for use across the power line. They're self healing and less likely to fail. Otherwise a 630 volt plastic capacitor will be much better than the original paper type. The chassis is probably used as the common ground in this set, often it's isolated and a seperate B- line is used. Remember that one side of the power cable is tied directly to B- so if that's the active wire, the chassis will be live.
Remember the electrolytics are polarized. Let's know if you're still having trouble.
Cheers, Don Black.
::Yes, I do have a schematic, norm gave me one. Replaced tubes already to see if hum goes away..no luck. C14?..looks like its across the main line. Which way does the cap go +/-, or does it matter? I thought you couldnt put a cap across the wall a/c, wouldnt it go poof, maximum smoke. Or is the value small enough not to burn up? Isnt the chassis the ground on this set?
::
::I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
::Don Black.
::
:::Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
:::each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
:::Don Black.
::
::::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

:going to replace the .006 cap on the plate of the 43 tube...but with what, I think the smallest cap I have is a .047
:
:Hi Sean, That capacitor across the mains is small enough to not draw too much current. Actually, it's a bit large by today's standards, probably about 0.047µf would be a better choice but it's not critical. The set will work without it but might pick up some interference that the capacitor will block. It's a non polarized capacitor so it doesn't matter which way it's connected. If possible get one of the capacitors designed for use across the power line. They're self healing and less likely to fail. Otherwise a 630 volt plastic capacitor will be much better than the original paper type. The chassis is probably used as the common ground in this set, often it's isolated and a seperate B- line is used. Remember that one side of the power cable is tied directly to B- so if that's the active wire, the chassis will be live.
:Remember the electrolytics are polarized. Let's know if you're still having trouble.
:Cheers, Don Black.
:::Yes, I do have a schematic, norm gave me one. Replaced tubes already to see if hum goes away..no luck. C14?..looks like its across the main line. Which way does the cap go +/-, or does it matter? I thought you couldnt put a cap across the wall a/c, wouldnt it go poof, maximum smoke. Or is the value small enough not to burn up? Isnt the chassis the ground on this set?
:::
:::I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
:::Don Black.
:::
::::Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
::::each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
::::Don Black.
:::
:::::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

Hi,
That value should still work, but a .01 would be a bit closer, and close enough to original manufactured tollerences.

::going to replace the .006 cap on the plate of the 43 tube...but with what, I think the smallest cap I have is a .047
::
::Hi Sean, That capacitor across the mains is small enough to not draw too much current. Actually, it's a bit large by today's standards, probably about 0.047µf would be a better choice but it's not critical. The set will work without it but might pick up some interference that the capacitor will block. It's a non polarized capacitor so it doesn't matter which way it's connected. If possible get one of the capacitors designed for use across the power line. They're self healing and less likely to fail. Otherwise a 630 volt plastic capacitor will be much better than the original paper type. The chassis is probably used as the common ground in this set, often it's isolated and a seperate B- line is used. Remember that one side of the power cable is tied directly to B- so if that's the active wire, the chassis will be live.
::Remember the electrolytics are polarized. Let's know if you're still having trouble.
::Cheers, Don Black.
::::Yes, I do have a schematic, norm gave me one. Replaced tubes already to see if hum goes away..no luck. C14?..looks like its across the main line. Which way does the cap go +/-, or does it matter? I thought you couldnt put a cap across the wall a/c, wouldnt it go poof, maximum smoke. Or is the value small enough not to burn up? Isnt the chassis the ground on this set?
::::
::::I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
::::Don Black.
::::
:::::Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
:::::each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
:::::Don Black.
::::
::::::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things

:I,m just wondering what the .25 cap across the main power line does?
:
:Hi,
:That value should still work, but a .01 would be a bit closer, and close enough to original manufactured tollerences.
:
:
:
:::going to replace the .006 cap on the plate of the 43 tube...but with what, I think the smallest cap I have is a .047
:::
:::Hi Sean, That capacitor across the mains is small enough to not draw too much current. Actually, it's a bit large by today's standards, probably about 0.047µf would be a better choice but it's not critical. The set will work without it but might pick up some interference that the capacitor will block. It's a non polarized capacitor so it doesn't matter which way it's connected. If possible get one of the capacitors designed for use across the power line. They're self healing and less likely to fail. Otherwise a 630 volt plastic capacitor will be much better than the original paper type. The chassis is probably used as the common ground in this set, often it's isolated and a seperate B- line is used. Remember that one side of the power cable is tied directly to B- so if that's the active wire, the chassis will be live.
:::Remember the electrolytics are polarized. Let's know if you're still having trouble.
:::Cheers, Don Black.
:::::Yes, I do have a schematic, norm gave me one. Replaced tubes already to see if hum goes away..no luck. C14?..looks like its across the main line. Which way does the cap go +/-, or does it matter? I thought you couldnt put a cap across the wall a/c, wouldnt it go poof, maximum smoke. Or is the value small enough not to burn up? Isnt the chassis the ground on this set?
:::::
:::::I've just noticed the other replies and agree with them, replace all the electrolytic and paper capacitors. If someone has already replaced the paper ones with modern plastic type, they are still probably OK but make sure you replace that 0.006µf from the 43 plate (it should go to ground, not the grid according to the schematic) and the electrolytics.
:::::Don Black.
:::::
::::::Hi Sean, Forget a bridge rectifier for the filaments (heaters). This set uses indirectly heated tubes that have their cathodes electrically isolated from the heating element. It's possible that one of them has a heater to cathode short causing hum but the remedy is to replace the bad tube. The B+ supply is a little unusual on this set. It has a separate supply for the speaker field (using one half of the rectifier) and the other half provides the set's B+. Here, the filter choke L2 is in the negative lead and the voltage drop across it is used as back bias for the output tube. It's filtred by the 200k resistor R6 and 0.25 µf capacitor C8 (part numbers are hard to read but I think they're the right numbers). The electrolytic filter capacitors are connected with their positive ends both to the B+ line but the negatives of go to
::::::each side of the filter choke, not joined together. It's a common mistake to wire these incorrectly and cause hum. Check it against the schematic. If that's not the problem, short the grid to cathode on the output and 2nd. Detector tubes and see if that stops the hum. It will help locate the faulty stage. The oscilloscope should help but remember this is a transformerless set with a live chassis. If you don't have an isolation transformer the scope can short out through its ground connection to the receiver chassis. At least make sure the power plug is the right way round so the chassis (B-) is on the neutral side. Have you replaced C14 across the incoming power? Sometimes reversing the polarity of the power will solve hum problems (turn the power plug over). Do you have a schematic for the set? I may have a clear copy if not, let's know if you need one snd I'll email it to you.
::::::Don Black.
:::::
:::::::I have replaced the caps on the airline 62-104..hum is still there. replaced the volume control 23k ohms with a 15k with a switch. It didnt do anything other than I can now turn it off!(thats a bonus) I think I am begining to understand what the guy meant when he said the hum was hard to get out of this set. The volume still shuts off at 3/4 rotation of volume. When it is "shut off", you can hear the station real soft, so I guess the volume control wasnt bad or too far off original value. Oh well we're gettin there. Thinking maybe I should use my scope to find hum...or put a bridge rectifier on the filament side of things