Description: Radio amateur, ham radio blog
But first, I do actually have experience in blowing the finals. That happended under testing prior to leaving, and all it took was 9.5 Volts for my 9 V build and what I thought was a dummy load, but which might have been an open circuit load. One BS170 developed a short between drain and gate with the result that 9.5 Volts was passed directly into the outputs of the driver IC5, 74ACT08, so IC5 blew as well.
My three tips for avoiding such failures are:
This is screen number 39 for this clock, all of them selectable by rotating a rotary encoder. The project, with Arduino Mega hardware and software is documented on Github , where the current release is v.1.6.0 (2023-04-14).