Gordon,
The diode you listed in your post has a max reverse voltage of 50 volts.? That is 13 volts short of the 63 volts I calculate for 40 watts in a pure resistive 50-ohm load.? I have found that all pin diodes are hundreds or thousands of dollars for a minimum purchase required to replace the eight diodes.
Maybe go back to relays for LPF selection and change the program to keep the relays on for the selected band to allow for QSK CW operation?? I believe that you did this for your DE.
Another chain of diagnosis might be the voltage doubling circuit (as you pointed out in a prior post).? There may be an issue with the doubler voltage not being filtered enough, or the capacitor is on the high side of the ESR spec.
As I have stated before, I am NOT an RF engineer, just an industrial controls engineer tinkering with radio stuff.
73
Evan
AC9TU
