iFixit

Set the circuit board beside the case, being careful not to damage the thin wires going to the earphone jack and speaker.

The earphone jack is composed of a few strips of metal. It also acts as a switch - when the earphone is inserted, contacts are opened to disconnect the built-in speaker.

Carefully lift out the earphone jack assembly and set it aside from the case, still connected to the speaker.

The speaker is fastened to the case with small clips held down by two nuts.

Use a 5mm nutdriver to loosen the nuts.

You may find the space a bit tight to fit a nutdriver in close to the case edge. If so, you can try using needlenose pliers instead to loosen the nuts.

Once the nuts are loosened, you can separate the speaker from the case.

Here's the circuit board, earphone jack and speaker after they've been removed from the case.

Notice that there are components mounted on both sides of the circuit board. Perhaps the resistors and capacitors on the solder-side were a last minute design change?

On the other hand, the circuit board is so tightly crammed on the component side there probably wasn't enough room for everything on one side.

Here's a closeup of the solder-side of the circuit board.

Unlike modern electronics, you can tell this radio was assembled and soldered by hand.

I wonder what mark my old high school electronics teacher would have given to this work? :)

Here's the component side of the circuit board.

You can see the various components in these views of the circuit board. Remember, these are all discrete components here -- no integrated circuits! But state of the art at the time, a lot of circuitry crammed into a small space.

Six of the gray components with an oval cross-section (marked or stamped with "Sony") are transistors.

The 7th similar looking gray component is a varistor. It's the one at the front left of the circuit board in the 3rd photo in this series.

Say, do they still teach the resistor colour code in schools these days? :)

Here's a closeup of the volume dial / on-off switch

An eccentric cam in the middle of the dial opens and closes a metal contact (marked with green square) to disconnect/connect the power to the circuits.