If C202 (47pf) SHORTED, you would expect potentially what is being seen.
If the 80 meter filter were invoked, and your frequency is above that, the input of the filter might act like a short.
If D15 shorted, this could happen, or if Q24 shorted this could happen
If the teflon insulation on the orange wire melted (this is not likely) then the output of the transformer might be shorted
If the antenna output connector or coax shorted, this low output might happen.
But chasing down every one of those is very time consuming.? ?Again, it might be easier to just look at what is coming out of the orange wire, disconnected from everything else.....much simpler than all the other techniques.
Anyone see something better?
Gordon KX4Z
On Fri, Feb 28, 2025 at 4:48?PM Gordon Gibby KX4Z via <docvacuumtubes=[email protected]> wrote:
But I can’t figure out is how disconnecting a Lowpass filter would result in a lower voltage. It should result in a higher voltage. ?
I tried to look for what things might be shorting out. There’s a chance that the high-voltage system is shorting out but it’s only connected by 47 pf?
?and that’s not much. ?
Gordon?
On Feb 28, 2025, at 16:35, Evan Hand via <elhandjr=[email protected]> wrote:
?
It should be possible to test the LPF selection process with a DMM.? Use USB, set the drive to 1 and the mic to 0.? Then, measure the voltages on the banded sections of the selection diodes.? Only one pair should be close to zero; the others should be close to the input voltage (12 volts) without the RF voltage doubler.
