The Vectrex accepts mains voltage in (230V or 120V depending on region).

The mains are instantly fused through a 250mA fuse.

The brown (live) and blue (neutral) go into the small brown board.

The neutral runs through a fuse and off to the transformer (in this case the black wire).

The live goes straight to the transformer (in this case the red wire).

The third wire is often internally connected to the transformers live side, and sometimes also connected on the board back to live, other time it doesn't connect on the brown board. Either way this wire is irrelevant; the transformer is just a 2 pin coil at the primary side.

The output of the transformer is a center-tapped 3 pin output. The single-color wire (usually white) is the center tap. Then either side (the other two wires, usually red) are +9VAC and -9VAC.

The center tap goes straight to the upright PCB, and the +-9VAC wires first pass through the front volume switch and back out to the upright PCB on the output wires (usually brown).

The CRT appears to be powered by the top 9VAC wire on the back of the power switch (one of the two red wires).

When this 9VAC wire is removed, the console still works fully in terms of controller and audio, but there is no CRT.

The circuit that powers all the logic and audio start with the lower 9VAC on the power switch (one of the two red wires).

There is a further set of regulators including a 5V LM340 IC that is responsible for the logic and audio.

A working stock Vectrex UK (240V) pulls around 120mA (21W).

A working stock Vectrex US (110V) pulls around 350mA (33W).