Dear Norm and Nostalgiaair:
I stepped away from a radio repair job for four years and recenlty started getting back into the project. I am so delighted to see this web site still functioning. Norm, I particularly remember how helpful you were.
Thank you for sharing all your expertise with newbies like myself.

Would you mind giving me some direction on my 1939 Zenith project?
I cleaned things up and got as far as the "smoke test". The radio is
putting out a strong 60 Hz buzz. Based on my reading,
my logical next step seems to be to check and replace capacitors. In particular,
the fixed capacitor that is rectifying the AC power supply input.
Is that a reasonable approach?

Thanks.
Regards
Paul Jebb

Hi Paul

Electrolytic filter caps should be replaced. They may be 10 mfd or other large value. Be sure voltage rating is at least as high as original. This should eliminate hum.

Other caps are most likely leaky. These can cause distortion, no sound, excessive current and other strange symptoms. Some find it easier to replace all paper caps.

Not sure of your radio model number but a schematic should be available here on nostalgiaair.

Norm

:Dear Norm and Nostalgiaair:
:I stepped away from a radio repair job for four years and recenlty started getting back into the project. I am so delighted to see this web site still functioning. Norm, I particularly remember how helpful you were.
:Thank you for sharing all your expertise with newbies like myself.
:
:Would you mind giving me some direction on my 1939 Zenith project?
:I cleaned things up and got as far as the "smoke test". The radio is
:putting out a strong 60 Hz buzz. Based on my reading,
:my logical next step seems to be to check and replace capacitors. In particular,
:the fixed capacitor that is rectifying the AC power supply input.
:Is that a reasonable approach?
:
:Thanks.
:Regards
:Paul Jebb
:

:Hi Paul
:
: Electrolytic filter caps should be replaced. They may be 10 mfd or other large value. Be sure voltage rating is at least as high as original. This should eliminate hum.
:
: Other caps are most likely leaky. These can cause distortion, no sound, excessive current and other strange symptoms. Some find it easier to replace all paper caps.
:
: Not sure of your radio model number but a schematic should be available here on nostalgiaair.
:
:Norm
:Thaks Norm,
That should do it. Looking forward to keeping in touch.
Paul
::Dear Norm and Nostalgiaair:
::I stepped away from a radio repair job for four years and recenlty started getting back into the project. I am so delighted to see this web site still functioning. Norm, I particularly remember how helpful you were.
::Thank you for sharing all your expertise with newbies like myself.
::
::Would you mind giving me some direction on my 1939 Zenith project?
::I cleaned things up and got as far as the "smoke test". The radio is
::putting out a strong 60 Hz buzz. Based on my reading,
::my logical next step seems to be to check and replace capacitors. In particular,
::the fixed capacitor that is rectifying the AC power supply input.
::Is that a reasonable approach?
::
::Thanks.
::Regards
::Paul Jebb
::

:Thanks Norm,
I'm off. Regards Paul

Hi Paul
:
: Electrolytic filter caps should be replaced. They may be 10 mfd or other large value. Be sure voltage rating is at least as high as original. This should eliminate hum.
:
: Other caps are most likely leaky. These can cause distortion, no sound, excessive current and other strange symptoms. Some find it easier to replace all paper caps.
:
: Not sure of your radio model number but a schematic should be available here on nostalgiaair.
:
:Norm
:
::Dear Norm and Nostalgiaair:
::I stepped away from a radio repair job for four years and recenlty started getting back into the project. I am so delighted to see this web site still functioning. Norm, I particularly remember how helpful you were.
::Thank you for sharing all your expertise with newbies like myself.
::
::Would you mind giving me some direction on my 1939 Zenith project?
::I cleaned things up and got as far as the "smoke test". The radio is
::putting out a strong 60 Hz buzz. Based on my reading,
::my logical next step seems to be to check and replace capacitors. In particular,
::the fixed capacitor that is rectifying the AC power supply input.
::Is that a reasonable approach?
::
::Thanks.
::Regards
::Paul Jebb
::

Hi Paul,
Replace the electrolytic filter caps as Norm suggests. I usually also replace the audio coupling cap to the power output tube(s) grid. At that point you can safely power up the radio and see what happens, without risking damage to the power transformer, field coil, or output transformer. You can then proceed to recap the rest of the radio, one capacitor at a time, and test after installation of each capacitor.

Poston

:Hi Paul
:
: Electrolytic filter caps should be replaced. They may be 10 mfd or other large value. Be sure voltage rating is at least as high as original. This should eliminate hum.
:
: Other caps are most likely leaky. These can cause distortion, no sound, excessive current and other strange symptoms. Some find it easier to replace all paper caps.
:
: Not sure of your radio model number but a schematic should be available here on nostalgiaair.
:
:Norm
:
::Dear Norm and Nostalgiaair:
::I stepped away from a radio repair job for four years and recenlty started getting back into the project. I am so delighted to see this web site still functioning. Norm, I particularly remember how helpful you were.
::Thank you for sharing all your expertise with newbies like myself.
::
::Would you mind giving me some direction on my 1939 Zenith project?
::I cleaned things up and got as far as the "smoke test". The radio is
::putting out a strong 60 Hz buzz. Based on my reading,
::my logical next step seems to be to check and replace capacitors. In particular,
::the fixed capacitor that is rectifying the AC power supply input.
::Is that a reasonable approach?
::
::Thanks.
::Regards
::Paul Jebb
::