07-28-2019, 07:13 PM
Today I grafted the rotor from 37-640 Philco tone control to the 45C. They have the same case. Possibly the shaft is longer in 640 but it will do.
I assembled the radio having installed the tone ctl and the tuning cap, and it was unstable. Then I realized I did not solder back the grid cap wure to the pentagrid. Hmmm....same problem. Then I remembered I have to solder the GND braid to one of the tuning cap screwes.
Then it worked normally.
However. I used the values for the tone ctl PN 30-4178 from Ray Bintliff's book, and it shows the permanently wired cap being 1nF, and then going CW it should engage 10nF and then 20nF in parallel.
So when only 1nF is engaged, the radio whistles, and then when 10nF is parallelled it plays fine with good highs.
So I wonder if the 1nF value is correct.
I will probably have to parallel an extra cap to the control, now that it's potted.
Anyone has the values for the 45, are those correct?
I assembled the radio having installed the tone ctl and the tuning cap, and it was unstable. Then I realized I did not solder back the grid cap wure to the pentagrid. Hmmm....same problem. Then I remembered I have to solder the GND braid to one of the tuning cap screwes.
Then it worked normally.
However. I used the values for the tone ctl PN 30-4178 from Ray Bintliff's book, and it shows the permanently wired cap being 1nF, and then going CW it should engage 10nF and then 20nF in parallel.
So when only 1nF is engaged, the radio whistles, and then when 10nF is parallelled it plays fine with good highs.
So I wonder if the 1nF value is correct.
I will probably have to parallel an extra cap to the control, now that it's potted.
Anyone has the values for the 45, are those correct?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
