Updated: 7 Feb 2022 ZX80 general On the pcb bottom of a ZX80 there is a soldering option choose between standard or inverted video. Simple transistor mod for ZX80/ZX81 For Timex 1000 see underneath. This transistor mod is enough most of the time for great picture output quality on a ZX80 or ZX81 (source: link). This … Continue reading ZX80/ZX81/TS1000 composite video mods