01-25-2023, 01:11 AM
Hi Mr. Big,
Read your marked up schematic. I don/t think that it makes too much difference which side of R15 that the B+ to the output stage connects to. It should probably be on the other side of R15 but 2 bigger issues:
I compared this schematic to a FADA 1000, also a 6 tube set. Amazingly, except for Screen and B+ for all tubes other than the Output, Plate, the FADA having a loop antenna vs the CoRadio having a transformer for a long line antenna, and the presence of a wave trap, the FADA 1000 is remarkably similar to the CoRadio. A link to the FADA 1000 Schematic from Nostalgia Air is below:
http://www.nostalgiaair.org/PagesByModel...005622.pdf
The wave trap may be there if this radio was popular in the Great Lakes area or other maritime areas, as believe it or not, there was long wave marine communication via Morse Code (I remember hearing this on radios as a kid in the 60s, especially on fall nights.)
The most glaring issue is the 1st RF (12SK7) Screen which should be the B+ Value of 69V that the Output tube screen and IF Plate and screen should be, instead of almost zero V Check the wiring from the 1st RF Screen to the Convertor (12SA7) Screen and B+ to the Convertor side of the 1st IF transformer. Start out by ohming it. You may have a bad connection despite your great workmanship. Reheat them/ The lack of screen voltage is likely killing the RF Amp.
The other issue is the value of coupling cap C5 between the RF Amp plate and the Convertor grid and the coupling cap for the oscillator coil. You have a "?" for their values. For the FADA 1000, they are both 100pF
Also verify that you have the Antenna coil connected to the RF Stator of the tuning cap (larger plates) instead of the Oscillator (smaller plates). This will detune the Oscillator, and there would be no input to the RF like there should be.
Hope this helps.
Read your marked up schematic. I don/t think that it makes too much difference which side of R15 that the B+ to the output stage connects to. It should probably be on the other side of R15 but 2 bigger issues:
I compared this schematic to a FADA 1000, also a 6 tube set. Amazingly, except for Screen and B+ for all tubes other than the Output, Plate, the FADA having a loop antenna vs the CoRadio having a transformer for a long line antenna, and the presence of a wave trap, the FADA 1000 is remarkably similar to the CoRadio. A link to the FADA 1000 Schematic from Nostalgia Air is below:
http://www.nostalgiaair.org/PagesByModel...005622.pdf
The wave trap may be there if this radio was popular in the Great Lakes area or other maritime areas, as believe it or not, there was long wave marine communication via Morse Code (I remember hearing this on radios as a kid in the 60s, especially on fall nights.)
The most glaring issue is the 1st RF (12SK7) Screen which should be the B+ Value of 69V that the Output tube screen and IF Plate and screen should be, instead of almost zero V Check the wiring from the 1st RF Screen to the Convertor (12SA7) Screen and B+ to the Convertor side of the 1st IF transformer. Start out by ohming it. You may have a bad connection despite your great workmanship. Reheat them/ The lack of screen voltage is likely killing the RF Amp.
The other issue is the value of coupling cap C5 between the RF Amp plate and the Convertor grid and the coupling cap for the oscillator coil. You have a "?" for their values. For the FADA 1000, they are both 100pF
Also verify that you have the Antenna coil connected to the RF Stator of the tuning cap (larger plates) instead of the Oscillator (smaller plates). This will detune the Oscillator, and there would be no input to the RF like there should be.
Hope this helps.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
