Specifications: Z80 with variable clock speed (IC 4049 oscillator).20 keys for the main input (16 hexadecimal keys for numeric input and keys labelled AD (for address), GO (to execute a program), + and -. Scanned with a 74C923 keyboard encoder. 6 seven segment displays with 8212 latch IC’s, also the source of a 1 bit speaker for sound.2716 EPOM with monitor MON1 or MON1b. 6116 SRAM for 2K RAM.
Memory decoding with 74LS138. Expansion connector in the form of a IC socket, 6116 compatible, extra chip select signals available. The expansions used this for extra RAM (RAM stack) e.g.
There was also a reset key in the standard configuration and the 1A optional upgrade had a function key.
Published in Talking Electronics Issue 10, 11 and 12.
PDF of the articles here.