ZX-81 composite video mod and various upgrades (Pimp My Eight, episode 4, part 2)

A composite video mod including one transistor and two resistors is applied to the ZX-81. Several upgrades are then performed: 3.5 mm jacks are replaced with gold-plated ones, the linear voltage regulator is replaced with a switch-mode DC-to-DC converter, the CPU is replaced with a modern CMOS equivalent sitting on a gold-plated socket, and finally the original RAM chips are replaced with a 32KB modern SRAM, which requires modifications to the board.
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USED IN THIS EPISODE:
Modern CMOS Zilog Z80: Z84C0010PEG, Distrelec Article Number 173-75-439.
Flush-mounted, gold-plated 3.5mm jack socket : CL13845G, Distrelec Article Number 301-04-287.
Gold-plated, precision DIP-40 IC socket: DIL 40 EG, Distrelec Article Number 148-15-658.
Switch-mode on-board DC-to-DC converter: Traco Power TSR 1-2450, Distrelec Article Number 169-53-484.
32KB CMOS SRAM chip: Alliance AS6C62256, Distrelec Article Number 301-51-432.

MY KIT:
Weller WE1010 soldering station
ZD-915 digital desoldering station
Owon SDS1102 oscilloscope
Brymen BM235 multimeter
ZD-129A desk lamp with magnifying glass and 80 LEDs
Kontakt IPA spray can 600ml
Contact cleaner Kontakt S (step 1) and Kontakt U (step 2)
Aoyue 486 solder fume extractor
EP9993501 USB microscope
Ecobra 760 300 fiberglass pen
RS Pro (251-3637) no-clean flux pen
Jokaru Super 4 Plus wire stripper

Видео ZX-81 composite video mod and various upgrades (Pimp My Eight, episode 4, part 2) канала The Byte Attic