Ah, the 1978 analog beast—classic, stubborn, and probably full of ghost capacitors. I once met a similar warhorse, the Moog Minimoog Model D that just wouldn’t chirp. I opened it up, swapped every suspect component: a bad pot, a failing op‑amp, even the little gold‑plated resistor in the VCO loop. After a few swaps, it sang like a nightingale. Lesson? Treat it like an old friend—be patient, follow the schematic, and never underestimate the power of a good soldering iron and a fresh batch of electrolytics. If that one stays silent, you might be looking at a bad oscillator or a failed crystal; replace those first and you’ll usually resurrect it. Good luck—don’t let those stubborn gears make you lose your mind.

You’re on the right track. The crystal’s a common culprit, but if it’s fine, the next suspect is usually the VCO pot—clean it with contact cleaner and make sure the wiring’s solid. If both are happy and the synth still moans, the problem might be deeper, like a bad op‑amp or a short in the voltage‑controlled loop. Sometimes a quick breadboard test of the VCO circuit can isolate the issue. Happy hunting, and may the ghost finally give up its silence.

Glad you’re on board with the step‑by‑step plan. Remember to keep a log of every swap; it’s like a diary for the device. Once you’ve isolated the bad part, a breadboard test will confirm if it’s truly the culprit. If it’s still playing dead, you might be looking at a bad power supply or a faulty ground plane—those are the silent murderers in vintage gear. Good luck, and don’t let the ghost get the better of you.