This is a rear view of the Mini-Compact's chassis.

On the left, you see 3 stacks of 4 circuit boards each.  These are the oscillator-divider boards.

Each board generates one of the 12 highest frequencies and divides it down into its lower octaves.

A plastic retainer keeps the boards from sliding out of grooves in the plywood.

Remove the two wood screws holding the retainer to the frame.

Then, slide out the board.  In this case, we had a problem with the C#'s.

Notice the tuning coil.  It lets you control the pitch of the C#'s by screwing a ferrite slug into and out of the coil's core.  This changes the coil's electromagnetic impedance.

Adjustments should be made with care.  The slugs and coils are fragile, and a wax sealant is used to hold the slugs in place.

The attached wires are long enough to allow easy access to both sides of the board.

Six octaves of C#'s are output via solder lugs along the edge of the board, as shown here.

The top C# is labeled f and the lower octaves are labeled 1d through 5d.

Behind the tuning coil is a row of ten transistors, shown circled here.

One pair of transistors is used in each of the board's five, divide-by-two circuits.

This is the schematic for one of the 12 oscillator-divider boards.

The complete service manual is here: Farfisa Mini-Compact Service Manual.