Sounds like a perfect dig site for a hobbyist who thinks a crystal oscillator is a relic. First, use the 555 in astable mode to generate a weak “pulsing” clock, but instead of feeding that straight into the 4017, mix it with a real random source. Grab a 4060 binary counter and feed its clock through a 74163 four‑bit latch that you clock with the 555. The latch will hold a pseudo‑random 4‑bit word, and the 4017 will count that word as a reset pulse each time the latch updates. That way, the counter doesn’t just march 0‑1‑2‑3… it jumps in a pattern that feels truly chaotic. For the “coin‑flip switch” you can use a cheap DPDT toggle and wire it into the 555’s reset pin. The moment you flip it, the 555 resets, the 4060 rolls, and the latch latches a new random nibble. That gives you a physical trigger that feels more like a relic than a microcontroller routine. Now, the sound board: keep the 74107 2‑input AND gate to shape the PWM output from a 555‑based tone generator, and feed that into a 2N3904 to drive the tip of a small 4‑track speaker. The MOSFET you mentioned—use a 2N2222 or a 2N3055 if you want something that smells of old power supplies. Those are in my hoard like fossils. For the “chiptune” itself, load a tiny micro‑ROM (like the 2716) with a handful of 8‑bit waveforms and a simple timer routine that steps through them. The 4017’s outputs can drive an old 74LS00 NAND to select which waveform to play. The randomness comes from the 4060 latch, so the track changes unpredictably each time you flip the switch. Don’t forget a 10‑µF electrolytic capacitor on the 555’s supply to dampen that classic hiss, and put a 220‑Ω resistor in series with every LED you use to avoid turning your box into a permanent flash mob. That’s all. Enjoy digging up that nostalgia—just don’t let the parts get lost in the dust, or I’ll have to send you on a scavenger hunt to find them again.

Nice, you’re tightening the loop just right. Put a 1‑µF cap and a 10‑kΩ resistor in series before the 74107, that’ll smooth out the PWM enough to make the hiss a whisper. The 74HC595 is a great idea—wire it to the 4017 outputs, shift the pattern one step each clock, so you get a faster shuffle that still feels like a dice roll. For the 7‑segment, feed the 4‑bit nibble into a pair of 74LS47 BCD‑to‑7‑seg drivers; the 74HC595 can source the segment lines, and the 74LS47 will take care of the multiplexing. Just remember to add a 330‑Ω current‑limiting resistor per segment to keep that display from starving the breadboard of current. Keep the 2N3055s in their protective box and you’ll always have a whiff of nostalgia whenever the chip fires up. Happy hunting, and may your components stay as fresh as fresh‑melted dough.