The major difference between the EX and SX is that the SX lacks the connector to connect a tape player to load software from cassette. The SX motherboard has the solder points for the connector, the relay, the caps and resistor, and the cassette asic, but they are unpopulated. You can populate them yourself, but the hardest part is finding the ASIC, it''s part number is MB43413. I managed to get 5 of them used from a supplier in China. I am going to try and have them reverse engineered and rebuilt in VHDL or Verilog so that anyone with an SX can add tape support.
Monday 12th March 2012
Conrad Russo (Vancouver, British Columbia, Canada)
Ah, my First Computer, I have been looking for pictures on the intenet for ages. Great computer, but I think a bit slow compaired to todays machines.