Building and testing a ZX Nucleon 512KB ver 3B from CSS Electronics

DIY ZX Nucleon 512KB ver 3B. This is the Czech clone of the Russian Pentagon microcomputer - itself a powerful clone of Sinclair ZX Spectrum 128

CPU: Z80A 3.5MHz
RAM: 512KB
Graphics: 256x192, 384x304, 512x192 monochrome. No attribute clash
Keyboard: 40 rubber keys
Sound: AY-3-8910A

The chip tester: https://8bit-museum.de/

Demoscene Demo: "Across The Edge"
Original Publisher: deMarche (Russia)

Music track: Within Us by Epic Spectrum
Source: https://freetouse.com/music
Background Music for Videos (Free)