This listing is for ZX81 video mod with backporch signal generator based on NE555

Fixies the problem with video signal quality on modern TV's.

Works well with ULA version 2C184E, not needed with the newer ULA since it creates correct composite video signal.

All boards are fully tested with ZX81.

The original RF modulator must be removed, using wires from through-hole type resistors makes installation easy.

PCB dimensions 28mm x 19.5mm