Check the listing for details. 🇬🇧 ZX81 Composite Video with Back porch mod. Condition: New. Listed at 15.38 USD. The ZX81 Composite video PCB replaces the RF modulator in the ZX81 which will give you a clearer and more stable picture on modern TV's This design is based off the schematics from zigg.net which have been around for many years and is tried and tested. To fit the PCB requires some soldering skills. Do not attempt this if you are not comfortable soldering. You risk damaging the ZX81 if you are not proficient in soldering. Installation: (See pictures for more details)(Cables are not included)Remove the lid from RF ModuleDesolder (or cut) the resistor connected to the RF output pin.Cut the 5V wire from the motherboard to the RF ModuleCut the input wire from the motherboard to the RF ModuleSolder cable from GND pin on the PCB to the GND track on the ZX81Solder cable from 5V pin on the PCB to the 5V wire on the ZX81 (On the motherboard, not on the RF Module)Solder cable from the IN pin on the PCB to the input wire on the ZX81 (On the motherboard, not on the RF Module)Solder cable from the OUT pin on the PCB to the RF output pin on the RF Module. Note: This backporch mod is not required for ZX81’s with a newer ULA or ULA replacement like the VLA81 that already produces a backporch signal. Please contact me if you have any queries. If you wish to buy more than one item at the same time, please let me know before you pay the invoice so I can check to see if postage costs can be reduced. Please check out my excellent Feedback for assurances. I do not sell anything I would not be happy to receive myself. I am always fair with my postage prices and as postage has increased significantly of late for larger items or those over 1kg, I will use a courier, which is the cheaper option for my customers. Where possible to save postage costs for my customers, I will use second class or economy delivery with the insured or signed for option. I am only human so please advise me if there is anything you’re unhappy about. I am an honest and reliable seller - I do want all my customers to be happy. If your item is urgent and you are happy to pay royal mail costs, please contact me so I can invoice you correctly. Many thanks for checking out my listings. Visit my store