This was Brazil's first Spectrum clone released in 1985, by Microdigital Electronica, from Sau Paulo, who had also released various ZX80 and ZX81 clones.
The machine is about 90-95% compatible with Spectrum software, due to some changes to the ROM.
There are a few notable improvements over the original Spectrum, firstly the machine is a fair bit taller, and has a grill on the top for better heat dispersal, there is a joystick port on the rear, but the one major difference between this machine and the Spectrum was that the sound was now via the modulated RF to the TV, rather than through the beeper on the circuit board.
There are of course also some changes of lettering on the keys, some Portuguese and Spanish symbols are included, while others such as the pound symbol are removed.
During this period of time, no importing of computers was allowed, so the TK90X became the first computer for millions of people, not only in Brazil, but in other Latin American countries.
The machine was replaced by the TK95, which although identical in performance, was housed in a case very similar to the Commodore Plus 4, it also housed changes to the Rom which made it more compatible with the original Spectrum, but changes to a diode caused some different incompatibilities, so owners would make modifications to the TK95, in the form of a switch, so most software would run.
This unit was very kindly donated by Marcus Vinicius Garrett Chiado.
The PSU was donated by Marcus's friend Wilton Abreu.
This exhibit has a reference ID of CH34149. Please quote this reference ID in any communication with the Centre for Computing History.
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