Hello All,
As usual, I have replaced all the paper and filter capacitors. I have also replaced the line resistor with a 126 ohm power resistor. I used a 500 ohm 225W adjustable resistor and have it set to 126 ohms. It runs very warm to the touch but it cannot burn the skin. This resistor works beautifully.
Anyway BC works perfectly but when I switch to Short Wave there is silence. I think I have the band switch cleaned. What else may I have overlooked? Could it be that the 78 can no longer oscillate at the SW frequencies?

Thanks,

Dave
The service data is here:
http://www.nostalgiaair.org/PagesByModel/866/M0018866.pdf

Dave,

If you haven't already, you could try substituting one of the 78s in the IF for the det/osc 78.

Radiodoc
**********

:Hello All,
: As usual, I have replaced all the paper and filter capacitors. I have also replaced the line resistor with a 126 ohm power resistor. I used a 500 ohm 225W adjustable resistor and have it set to 126 ohms. It runs very warm to the touch but it cannot burn the skin. This resistor works beautifully.
: Anyway BC works perfectly but when I switch to Short Wave there is silence. I think I have the band switch cleaned. What else may I have overlooked? Could it be that the 78 can no longer oscillate at the SW frequencies?
:
:Thanks,
:
:Dave
:The service data is here:
:http://www.nostalgiaair.org/PagesByModel/866/M0018866.pdf
:

Coils?

T.

Dave

As someone else mentioned, try another oscillator tube. They usually stop operating on higher frequencies first.

Norm

:Dave,
:
:If you haven't already, you could try substituting one of the 78s in the IF for the det/osc 78.
:
:Radiodoc
:**********
:
:
::Hello All,
:: As usual, I have replaced all the paper and filter capacitors. I have also replaced the line resistor with a 126 ohm power resistor. I used a 500 ohm 225W adjustable resistor and have it set to 126 ohms. It runs very warm to the touch but it cannot burn the skin. This resistor works beautifully.
:: Anyway BC works perfectly but when I switch to Short Wave there is silence. I think I have the band switch cleaned. What else may I have overlooked? Could it be that the 78 can no longer oscillate at the SW frequencies?
::
::Thanks,
::
::Dave
::The service data is here:
::http://www.nostalgiaair.org/PagesByModel/866/M0018866.pdf
::

Norm, All,
I was moving the band switch a little bit too far. If I move the contacts in just slightly I have short wave. If I pull it back out I have AM. It seems like it only has to be moved less then one centimeter one way or the other to change bands.

Thanks for your help,

Dave

:Dave
:
: As someone else mentioned, try another oscillator tube. They usually stop operating on higher frequencies first.
:
:Norm
:
::Dave,
::
::If you haven't already, you could try substituting one of the 78s in the IF for the det/osc 78.
::
::Radiodoc
::**********
::
::
:::Hello All,
::: As usual, I have replaced all the paper and filter capacitors. I have also replaced the line resistor with a 126 ohm power resistor. I used a 500 ohm 225W adjustable resistor and have it set to 126 ohms. It runs very warm to the touch but it cannot burn the skin. This resistor works beautifully.
::: Anyway BC works perfectly but when I switch to Short Wave there is silence. I think I have the band switch cleaned. What else may I have overlooked? Could it be that the 78 can no longer oscillate at the SW frequencies?
:::
:::Thanks,
:::
:::Dave
:::The service data is here:
:::http://www.nostalgiaair.org/PagesByModel/866/M0018866.pdf
:::

Dave,

I had a similar problem on a Model 580, which was manufactured around the same time. It turned out to be an open osc coil on SW1 band.

Gary

:Hello All,
: As usual, I have replaced all the paper and filter capacitors. I have also replaced the line resistor with a 126 ohm power resistor. I used a 500 ohm 225W adjustable resistor and have it set to 126 ohms. It runs very warm to the touch but it cannot burn the skin. This resistor works beautifully.
: Anyway BC works perfectly but when I switch to Short Wave there is silence. I think I have the band switch cleaned. What else may I have overlooked? Could it be that the 78 can no longer oscillate at the SW frequencies?
:
:Thanks,
:
:Dave
:The service data is here:
:http://www.nostalgiaair.org/PagesByModel/866/M0018866.pdf
: