RF, automotive electronics, vacuum tubes, microwave, analog synth, microcontrollers...these are a few of my favorite things.
I bought this as a kit and assembled it with some help from my sons. What a blast! Heated bed upgrade, and working on an improved carriage. Polishing my rudimentary mechanical design skills and learning 1-2-3D...
I regularly use this nice Nixie multimeter, but the original AC volts measurement was lacking (peak * 0.707). I made a completely new AC measurement card based on an Analog Devices AD636 True RMS converter. Now it's better than new!
I found some cheap HD6303 (MC6801 compatible) MCU and thought it'd be fun to go back to the ancestor of the 6809, 68HC11, 6502... It was fun for a while but, gosh, what a lot of slogging to get anything done with a single index register!