Hi Steve,
Good to hear about your 813 progress... and employing the GFZ audio driver board. It sounds like a FB rig.
Take a look at pages 4 to 9 in this 4-1000A plate modulated "Fabio" thread. We all beat the sequencing subject to death. You should find many ideas to proceed. If you still have questions, ask away.
http://amfone.net/Amforum/index.php?topic=33816.75
Fabio is still working FB with this elaborate key up / unkey sequencing box. The key is being able to adjust key up and unkey timing and sequencing order if you run into problems.
BTW, the one thing that helped to cure my T/R arcing problems was putting a 5K power resistor in series with a vac relay across the mod reactor that quenched the arc on unkey. The reactor/mod iron power has to go somewhere. Start with that technique and go from there. It may simplify things for you.
** The cathode CT voltages always remain at low voltage with the 50K (cutoff bias) across the contacts to ground. A small 3A relay with a 50K two watt resistor will work FB there. Just like the commercial linear amps.
T
*** Coming soon:
"The Summer of Antennas." Watch for a new thread featuring
ten new multi-element antenna arrays - designed, built and raised at K1JJ over the summer/fall. Final testing and optimization is in progress. Pictures and performance data coming soon....