Bryan,
Point F should be close to the supplied voltage when keyed without any RF input to the amp.? This is because there is no RF pumping to get the voltage up using D2, D9, D10, D4, and C10 as a voltage doubler.? 9.3 volts seems low.? It should be closer to 12.75-1.4=11.35volts though not too low.? I would verify that the diodes are installed correctly.? Also, check the D4/D8 junction to confirm that there is supply voltage there when the PTT is enabled, and no RF is being fed to the input BNC.? Finally, check on Q3 Drain voltages.? It should be the same as point F.
What happens to point F when you supply RF to the input?? It should be over 2x the peak RF voltage to ensure that the diodes remain off.
You may have stated what band it is built for, but could you please repeat it as I can not seem to find it.? Higher frequencies will act differently than lower frequencies.? I am comparing it to my 40meter QCX and Amp.
73
Evan
AC9TU
