04-15-2016, 10:36 PM
The field coil on the speaker is part of the power supply filter. It does double duty generating the electrostatic field for the speaker. If your speaker is not connected, it breaks the high voltage path, so you won't get any DC high voltage at any of the tubes, only at the rectifier cathode and the positive of input filter cap (usually.) The schematics can be confusing, as they usually show the field coil in the power supply section, but it is actually on the speaker. Sounds like you have another choke, too, which might add a bit of confusion.
Check the continuity across the output transformer primary. If it is good, connect your speaker, power up, and you should have plate voltage at all tubes. If not, start with the input cap (the one connected directly to the rectifier cathode) and trace the high voltage path with a dc voltmeter through the field coil, the other choke, both sides of the output transformer primary to the plate of the 42 amp tube. Referenced to the chassis ground, you should see a voltage drop at each test point. Whatever amount the schematic says.
Let us know what happens.
It's a good idea to limit the AC current with a variac or dim bulb tester the first time you power up, just in case of shorts.
Check the continuity across the output transformer primary. If it is good, connect your speaker, power up, and you should have plate voltage at all tubes. If not, start with the input cap (the one connected directly to the rectifier cathode) and trace the high voltage path with a dc voltmeter through the field coil, the other choke, both sides of the output transformer primary to the plate of the 42 amp tube. Referenced to the chassis ground, you should see a voltage drop at each test point. Whatever amount the schematic says.
Let us know what happens.
It's a good idea to limit the AC current with a variac or dim bulb tester the first time you power up, just in case of shorts.
John Honeycutt