Circuit board only, NO components are included in this listing.

Free standard post and packaging, I aim to post same day but will post next day at the latest Monday to Friday except Bank Holidays.

For bulk pricing please contact me via Ebay messages.

Circuit board project for the ZX81 video modification with the option to add a back porch function if needed, fully compatible with the ZX80.

Designed to fit perfectly inside the RF modulator, this mod will provide a composite video signal to allow you to view your ZX81 on a modern TV or monitor. It can be fitted outside the RF modulator if preferred in a suitable spot inside the ZX81 casing.

This modification supports a ULA that doesn't generate the back porch part of the video output, if you have a 2C210E ULA which does support a back porch then simply omit the NE555 timer IC. This is probably the best version of the composite mod available for the ZX81 by far.You can see the mod being fitted to a ZX81 here:
Click here to see installation method



If you prefer a completed kit please see my listing number 226484575198


Parts needed to complete this board are listed below.

Qty       Value      Component Package                            PCB POSITION
2x        10K         Metal Film Resistors Axial DIN204       R1, R2
1x        68R         Metal Film Resistor Axial DIN204         R3
1x        56R         Metal Film Resistor Axial DIN204         R4
1x       10nF        Ceramic Capacitor 5mm                       C2
1x       820pF      Ceramic Capacitor 5mm                       C3
1x       82pF        Ceramic Capacitor 5mm                       C4
1x       22uF        Electrolytic Capacitor Radial 6.3mm     C1
2x      1N4148    Diodes DO-35                                       D1, D2
2x      BC337      Transistors TO-92                                 Q1, Q2
U1     NE555      Timer IC DIP-8                                      U1