Damn. I assumed it would be six components and a battery. Presumably some obsolete transistors are involved?
It is a simple circuit, less than 20 components including the pots, values and transistor types varying by version (FZ-1, FZ-1A, etc, FZ-1S being quite different). The original transistor type can still be bought, though they are obsolete, and newer ones might not sound quite like the old ones, but you can still build the circuit very cheaply and use other transistors with similar specs. That said, having not seen the layout inside the control cavity, no idea how easy or difficult it would be to work on the original circuit.
