03-19-2015, 09:58 PM
Bob, the voltages you measured look correct. There should be - 1 V on the grid of the 75, which is developed across the wirewound bias resistor. The other negative grid voltages you measured on the other tubes are also correct.
As to the antenna coil, it does measure as if the lower .7 ohm section is open. This part of the coil is only used for the SW band, so for testing purposes on AM broadcast, you can short it to ground for testing. Connect a ground wire to chassis to the end of the 10K not connected to the antenna terminal.
Have you checked for proper oscillator operation by bringing a transistor radio tuned 455 Khz higher than the dial freq and listening for a carrier as you tune the dial?
As to the antenna coil, it does measure as if the lower .7 ohm section is open. This part of the coil is only used for the SW band, so for testing purposes on AM broadcast, you can short it to ground for testing. Connect a ground wire to chassis to the end of the 10K not connected to the antenna terminal.
Have you checked for proper oscillator operation by bringing a transistor radio tuned 455 Khz higher than the dial freq and listening for a carrier as you tune the dial?
