"It then sets the fan for full speed operation to bleed off the 60 V power and waits for the power button to be released."
I don't think fan is set to high speed to bleed down the 60 V supply. I think it is set to low speed but may revert to high speed when the firmware shuts down with 60 V is still present. Try this simple test - With KPA500 powered and On, use menu to set minimum fan speed 6. Then shut down with the front panel On button. Fan immediately reduces to speed 1 and holds speed 1 until it slows down as the 60 V supply bleeds down. The firmware could detect that 60 V has not decayed below min monitor threshold and issue a fault. That fault code could perhaps alert the operator to turn off the rear panel power switch and seek assistance. Better to be alerted at shutdown time than find the fans still running the next day. There is a potential safety issue with a stuck 60 V enable relay. The interlock switch is in the relay coil coil circuit and offers no protection if the relay is stuck on. On the other hand - how often does the 60 V enable relay fail .... 73, Andy, k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com