After replacing electrolytics, which went well, and replacing most of the caps, I still have a problem with this radio.. First of all the bass level at the tone control is really more hot, but After the radio gets really good and hot, the AM band just goes away.. The 6sf5 tests really weak, and the so does the 6H6 and the 6sa7 as well..Any answers, where to check?

Hi Jesse

The 6H6 and 6SF5 won't be the problem. They can test weak and still work fine in a radio.

Does the radio just quit or fade out with distortion? 6SA7 could be a problem if the radio all of a sudden stops operating. If volume goes down and you hear distortion could be loss of bias on 6K6 output tube. Measure voltage between pin #5 and pin #8. Pin #5 should be negative 15 volts.

http://www.nostalgiaair.org/PagesByModel/800/M0014800.pdf

Norm

:After replacing electrolytics, which went well, and replacing most of the caps, I still have a problem with this radio.. First of all the bass level at the tone control is really more hot, but After the radio gets really good and hot, the AM band just goes away.. The 6sf5 tests really weak, and the so does the 6H6 and the 6sa7 as well..Any answers, where to check?
:

:Hi Jesse
:
: The 6H6 and 6SF5 won't be the problem. They can test weak and still work fine in a radio.
:
: Does the radio just quit or fade out with distortion? 6SA7 could be a problem if the radio all of a sudden stops operating. If volume goes down and you hear distortion could be loss of bias on 6K6 output tube. Measure voltage between pin #5 and pin #8. Pin #5 should be negative 15 volts.
:
:http://www.nostalgiaair.org/PagesByModel/800/M0014800.pdf
:
:Norm
:

Norm,

Thank you for your help.. The Radio just quits, and if you turn up the volume knob, you can hear what sounds like a small amount of static, then If I turn off radio and let cool off, turn back on it works and then when radio re heats, it does the same thing.

Hi Jesse

The 6SA7 could cause that if it stops oscillating. Other tubes could also be temperature sensitive. Sometimes the internal cathode connection opens with heat.

Since you have a tube tester allow tubes to heat for a period of time then test. Might increase filament voltage a little to speed up the process.

Norm

::Hi Jesse
::
:: The 6H6 and 6SF5 won't be the problem. They can test weak and still work fine in a radio.
::
:: Does the radio just quit or fade out with distortion? 6SA7 could be a problem if the radio all of a sudden stops operating. If volume goes down and you hear distortion could be loss of bias on 6K6 output tube. Measure voltage between pin #5 and pin #8. Pin #5 should be negative 15 volts.
::
::http://www.nostalgiaair.org/PagesByModel/800/M0014800.pdf
::
::Norm
::
:
:Norm,
:
: Thank you for your help.. The Radio just quits, and if you turn up the volume knob, you can hear what sounds like a small amount of static, then If I turn off radio and let cool off, turn back on it works and then when radio re heats, it does the same thing.
: