In late 70s, a 6502 based board that had a Basic rom. Ohio Scientific if I recall correctly. I had a surplus Teletype corp ASR-33 to use as the main I/O. Later I built a Z-80 board and then got into Heathkit H-89 CRT based Z-80 system, moved on to Kaypro CP/M system and then the early 8088 IBM PC clone machines.