Measure voltage between pins #5 and #8 on your 35L6GT. Pin #5 must be 5 volts or so, negative. If it's not negative the tube will draw excessive current, overheat & distort.
Both 35L6GT & 35Z5GT will operate hotter than other 12 volt tubes.
Norm
:I've got a Sentinel 293T that I've recapped and replaced all of the resistors in the power circuit. The radio gets fair reception but the 35L6GT output tube gets a lot hotter than I think is normal. After about 10 minutes, it's so hot that I turn the radio off. The tube test's good and I've used two others that react the same. I got the schematic off Nostalgia Air but it doesn't have the working voltages. Any ideas, thoughts, or suggestions???
:Hi Leon
:
: Measure voltage between pins #5 and #8 on your 35L6GT. Pin #5 must be 5 volts or so, negative. If it's not negative the tube will draw excessive current, overheat & distort.
:
: Both 35L6GT & 35Z5GT will operate hotter than other 12 volt tubes.
:
:Norm
:
::I've got a Sentinel 293T that I've recapped and replaced all of the resistors in the power circuit. The radio gets fair reception but the 35L6GT output tube gets a lot hotter than I think is normal. After about 10 minutes, it's so hot that I turn the radio off. The tube test's good and I've used two others that react the same. I got the schematic off Nostalgia Air but it doesn't have the working voltages. Any ideas, thoughts, or suggestions???
Voltage is close enough. These tubes run hot so maybe not a problem in your radio? Should be about the same temperature as a 35Z5GT.
Norm
:Thanks Norm
: I measured the voltages as you suggested. It reads negative 4.26 volts. I assume this is O.K.
:
::Hi Leon
::
:: Measure voltage between pins #5 and #8 on your 35L6GT. Pin #5 must be 5 volts or so, negative. If it's not negative the tube will draw excessive current, overheat & distort.
::
:: Both 35L6GT & 35Z5GT will operate hotter than other 12 volt tubes.
::
::Norm
::
:::I've got a Sentinel 293T that I've recapped and replaced all of the resistors in the power circuit. The radio gets fair reception but the 35L6GT output tube gets a lot hotter than I think is normal. After about 10 minutes, it's so hot that I turn the radio off. The tube test's good and I've used two others that react the same. I got the schematic off Nostalgia Air but it doesn't have the working voltages. Any ideas, thoughts, or suggestions???
Hi Leon
:
: Voltage is close enough. These tubes run hot so maybe not a problem in your radio? Should be about the same temperature as a 35Z5GT.
:
:Norm
::Thanks Norm
:: I measured the voltages as you suggested. It reads negative 4.26 volts. I assume this is O.K.
::
:::Hi Leon
:::
::: Measure voltage between pins #5 and #8 on your 35L6GT. Pin #5 must be 5 volts or so, negative. If it's not negative the tube will draw excessive current, overheat & distort.
:::
::: Both 35L6GT & 35Z5GT will operate hotter than other 12 volt tubes.
:::
:::Norm
:::
::::I've got a Sentinel 293T that I've recapped and replaced all of the resistors in the power circuit. The radio gets fair reception but the 35L6GT output tube gets a lot hotter than I think is normal. After about 10 minutes, it's so hot that I turn the radio off. The tube test's good and I've used two others that react the same. I got the schematic off Nostalgia Air but it doesn't have the working voltages. Any ideas, thoughts, or suggestions???
The 1973 edition of the RCA Receiving Tube Manual states that the maximum bulb temp for a 35C5 is 250 degrees Fahrenheit. (The 35L6 listing doesn't have a temp rating, but these two tubes are equivalent.) Normal operating temp is probably around 180 to 220 degrees.
If you are still worried about this, remove the chassis from the cabinet and attach the bulb or probe end of a cooking thermometer to the 35L6 and let the radio run for 20 minutes. If the temperature stays below 250 degrees, then it's probably OK.
::Thanks Norm
: I'll extend the run time and let you know if I have any problems.
:
:
:Hi Leon
::
:: Voltage is close enough. These tubes run hot so maybe not a problem in your radio? Should be about the same temperature as a 35Z5GT.
::
::Norm
:::Thanks Norm
::: I measured the voltages as you suggested. It reads negative 4.26 volts. I assume this is O.K.
:::
::::Hi Leon
::::
:::: Measure voltage between pins #5 and #8 on your 35L6GT. Pin #5 must be 5 volts or so, negative. If it's not negative the tube will draw excessive current, overheat & distort.
::::
:::: Both 35L6GT & 35Z5GT will operate hotter than other 12 volt tubes.
::::
::::Norm
::::
:::::I've got a Sentinel 293T that I've recapped and replaced all of the resistors in the power circuit. The radio gets fair reception but the 35L6GT output tube gets a lot hotter than I think is normal. After about 10 minutes, it's so hot that I turn the radio off. The tube test's good and I've used two others that react the same. I got the schematic off Nostalgia Air but it doesn't have the working voltages. Any ideas, thoughts, or suggestions???