The case suffered a redesign and the keyboard was said to be "semi-professional" (according to the Brazilian manufacturer), with the some additional commands that did not exist in the ZX Spectrums (for characters defined by the user — UDG), and more compatibility with the original ZX Spectrum. (some games did not run in TK 90X but ran alright in the TK 95).
There were one version with 48 kilobytes of RAM. Inside, the same processor: Z80A running at 3.58 MHz, a ROM chip, some RAM chips (old dynamic rams 4116 and 4416). Microdigital did some reverse engineering to develop a chip with the functions of the original ULA from Sinclair/Ferranti. The modulator was tuned to VHF channel 3 and the TV system was PAL-M (60 Hz). The cassette interface ran at a faster speed than the Spectrum. Only two peripherals were released by Microdigital — a light pen interface and a parallel printer interface. Some other small companies in Brazil released clone versions of : microdrive, interface 1, joysticks (like Kempston) and interface for an old PC drive. The games are almost pirate copies of the originals and the fans of the ZX Spectrum computer in Brazil were counted in tens of thousands.