Mostly Goodwill and Craigslist finds.
JVC JR-S301 receiver (rebuilt) Three tuners (Sansui TU-717, JVC T-X55, and MCS 3050) because they’re a cheap source of lights and knobs Sony TC-RX79ES tape deck (belts replaced) Sony DVP-CX860 300-disc changer (not great at feeding discs, I mostly use it as a depository after ripping the discs to FLAC) Onkyo CP-1030F turntable (automatic mode is wonky- it keeps resetting after 3 seconds of play)














The “default” mode for a USB keyboard allows submitting 6 keys + modifiers. Some boards define nontraditional input descriptors that allow more, but that mode is not guaranteed to work in places like the BIOS menu or naive KVM switches.
To avoid phantom keypresses when you hit three keys in a “square” on the matrix, a diode can be placed in series with each switch so current can’t go through an “indirect” route.