Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!

:Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!

I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.

::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
:
: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.

I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.

:::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
::
:: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
:
:I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.

:::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
::
:: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
:
:I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.

::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
:::
::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
::
::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.

I sould not try to answer posts with a new computer, and only one cup of coffee.
In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
Lewis

:::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
::::
:::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
:::
:::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
:
:I sould not try to answer posts with a new computer, and only one cup of coffee.
:In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
:Lewis
:
:Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
Johnny

::::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
:::::
::::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
::::
::::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
::
::I sould not try to answer posts with a new computer, and only one cup of coffee.
::In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
::Lewis
::
::Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
:Johnny

Hello again Johnny .. Yes, the old #37 is in its golden years .. I would get another 37 for future use.
Could last years still. But could just burn out the next time you turn it on.

:::::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
::::::
:::::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
:::::
:::::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
:::
:::I sould not try to answer posts with a new computer, and only one cup of coffee.
:::In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
:::Lewis
:::
:::Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
::Johnny
:
:Hello again Johnny .. Yes, the old #37 is in its golden years .. I would get another 37 for future use.
:Could last years still. But could just burn out the next time you turn it on.
:
:Sounds great. Thanks much for the help.
Johnny

::::::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
:::::::
::::::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
::::::
::::::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
::::
::::I sould not try to answer posts with a new computer, and only one cup of coffee.
::::In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
::::Lewis
::::
::::Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
:::Johnny
::
::Hello again Johnny .. Yes, the old #37 is in its golden years .. I would get another 37 for future use.
::Could last years still. But could just burn out the next time you turn it on.
::
::Sounds great. Thanks much for the help.
:Johnny

It might be a good idea to add a CL-90 thermistor to slowly ramp up the voltage and filament current. Greatest surge current is at turn-on as filaments heat up. Adding this makes it a lot easier on those aging tube filaments. Mouser has them. See: http://www.mouser.com/Search/ProductDetail.aspx?qs=K5ta8V%252bWhtYTYrFAkIfaLQ%3d%3d
Steve

:::::::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
::::::::
:::::::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
:::::::
:::::::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
:::::
:::::I sould not try to answer posts with a new computer, and only one cup of coffee.
:::::In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
:::::Lewis
:::::
:::::Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
::::Johnny
:::
:::Hello again Johnny .. Yes, the old #37 is in its golden years .. I would get another 37 for future use.
:::Could last years still. But could just burn out the next time you turn it on.
:::
:::Sounds great. Thanks much for the help.
::Johnny
:
:It might be a good idea to add a CL-90 thermistor to slowly ramp up the voltage and filament current. Greatest surge current is at turn-on as filaments heat up. Adding this makes it a lot easier on those aging tube filaments. Mouser has them. See: http://www.mouser.com/Search/ProductDetail.aspx?qs=K5ta8V%252bWhtYTYrFAkIfaLQ%3d%3d
:Steve
:
Hi Johnny, I got tired of trying to pick the right thermister for my radios and used a different solution. The thermister would provide more protection, but my solution also provides a little protection and the warmup time will be quicker. I install a power resistor sufficient to drop our 120V+ line voltage down by about 5 volts, closer to the old days. This dropping resister will also dampen the inrush current significantly, since the inrush current is primarily due to filament resistances being several times lower when cold as when hot. Calculate the value for about a 5v drop at the radios' normal line current (probably 10 - 50 ohms), then choose a power rating about double the 5v * line current ( 5w or 10w wirewound). Just put the resistor in series with the hot-side of the incoming AC.
Eddie

Hi

A flashing bright filament is common especially in European tubes. Happens more on tubes with high voltage filaments but can be bright on any tube.

These tubes have a coated filament. The coating causes fairly slow heating. If coating comes off or one part of the filament is thinner a tube filament will start out bright in that area.

I don't like a bright flash at turn on but nothing wrong with the tube.

Norm

::::::::::Hi folks! On my Silvertone 1828 the #37 tube (in this case the "Phase Changer" as called out on the schematic) glows very bright for a second or so when I turn the radio on. Then it returns to normal. What will cause this? The tube tests good. I'm not even sure how to begin to troubleshoot this if it is a problem. The radio works fine. Thanks!
:::::::::
::::::::: I see this has a transformer for the heaters. #37 may be just showing its age a little. I don't think there is anything wrong if the tube glows normal after it warms up.
::::::::
::::::::I just noticed it has another #37 for the AVC ..Try and swap the two. See if there is any difference by what socket the tube is in.
::::::
::::::I sould not try to answer posts with a new computer, and only one cup of coffee.
::::::In the series filament radio, the tubes have a very large change in resistance between cold and hot. the tube that warms up fastest gets a much higher Voltage than the others, and, therefore gets bright until the others catch up, therefore the ballast tube in some radios. On a parallel string, or tranformer operated, that shouldn't happen, so I'll have to agree that it just might be showing it's age. Swap 'em like Warren says, and lesee what happens.
::::::Lewis
::::::
::::::Alright! I swapped the two 37 tubes and the one that glows still glows even in the swapped position. So you are saying that this tube is just getting old and maybe I should replace it? Thanks!
:::::Johnny
::::
::::Hello again Johnny .. Yes, the old #37 is in its golden years .. I would get another 37 for future use.
::::Could last years still. But could just burn out the next time you turn it on.
::::
::::Sounds great. Thanks much for the help.
:::Johnny
::
::It might be a good idea to add a CL-90 thermistor to slowly ramp up the voltage and filament current. Greatest surge current is at turn-on as filaments heat up. Adding this makes it a lot easier on those aging tube filaments. Mouser has them. See: http://www.mouser.com/Search/ProductDetail.aspx?qs=K5ta8V%252bWhtYTYrFAkIfaLQ%3d%3d
::Steve
::
:Hi Johnny, I got tired of trying to pick the right thermister for my radios and used a different solution. The thermister would provide more protection, but my solution also provides a little protection and the warmup time will be quicker. I install a power resistor sufficient to drop our 120V+ line voltage down by about 5 volts, closer to the old days. This dropping resister will also dampen the inrush current significantly, since the inrush current is primarily due to filament resistances being several times lower when cold as when hot. Calculate the value for about a 5v drop at the radios' normal line current (probably 10 - 50 ohms), then choose a power rating about double the 5v * line current ( 5w or 10w wirewound). Just put the resistor in series with the hot-side of the incoming AC.
:Eddie
: