Build your own computer

[ By Melanie Swalwell on December 6, 2013 | Filed under: Blog | Tagged with: , , , , ]

In the long 1980s decade, some hardly souls in both New Zealand and Australia built their own computers.

New Zealand Microcomputer Club legend, Selwyn Arrow, recalls building his first computer (or part thereof):

It was either Christmas 77 or 78, more likely 1978…A copy of Byte magazine arrived…I read it twice, including all the ads.  It just opened up a whole new world…

I had decided that I would start with peripherals and then eventually we’d sort things out.  I was planning on using sockets and connectors and things that were surplus at work, you see, old bits, to make cards that plugged in. And eventually I realised there was this S100 interface, which meant that it was a socket with 100 pins.  Eventually I dropped that one… But in the meantime I was studying a book on microprocessors – the Z80 – which of course was in the [first computer he bought, the Exidy] Sorcerer.  So I wasn’t wasting my time totally.  I had this wonderfully large – by today’s standards – keyboard with all the bells and whistles on it.  I never really used it in warfare….I took it apart eventually.

Neil Breen was a programmer working for the (little known) New Zealand office of the (very well known) arcade games manufacturer, Taito.  He recalls:

I was building my first computer as an amateur on veroboard in 1976. I built several machines for myself.  My wife was running the local Plunket membership lists on a Z80-based machine with probably about 16k of RAM in the late 1970s.

Breen also built computers to sell onto others as a “sideline” when he was working for Taito.

Meanwhile, in Australia, Jim Rowe publishes plans for the EDUC-8 computer — credited as the first Australian “stored-program digital computer” in Electronics Australia, starting in August 1974.  My favourite account of building computers, however, comes from Eric Lindsay and Tom Moffatt in Electronics Today International (ETI) in 1982.  They describe the issues and problems each had in building a Microbee.  Lindsay bought one of the earliest kits and after much labour, had to send the kit back to the manufacturer. “They spent about four days on it before also giving up. The offending board was returned to the supplier as an example of problems, and with a new board my MicroBee started running and has been trouble-free since.” By contrast, Moffatt’s initial construction was trouble free, but,

Within an hour of completion, the first problem surfaced: heat, and lots of it… There is an old rule of thumb in the electronics business,…if a part is too hot to touch, it’s too hot! Just about every active part of the power supply produced painful burns. Inquiries to Applied Technology brought the response that ‘all the parts were running within their ratings’. [My friend] J.J. and I, being of a more conservative nature, found a source of Sinclair ZX81 plugpacks rated at 9.5 V/1.2 A… Another Hobart MicroBee user didn’t get there in time – his 12 V plugpack ‘blew its guts’ (1982).

Classic stuff, and not the only story I’ve heard of computers catching on fire.  Did you build your own computer?  How did it go?

2 thoughts on “Build your own computer

  1. Greetings
    The first computer I built was a SC/MP kit that had to be wire wrapped .
    I was a student at Mt Isa Mines at the time and was given this kit to assemble . Unfortunately I used pre cut wire wrap wires as the result was a mess . My mother lent me a crochet hook and I unwrapped all the wires and started again . This time I trimmed all the wires to required length . The kit consisted of a circuit board to be wire wrapped and a calculator case which used the buttons and display of the calculator case and a ribbon cable from the circuit board to the calculator case . One was able to write programs in machine code hex . I think I wrote a program to display words on the hex display .

  2. Greetings
    My second computer was a single chip microprocessor computer called 6801 . What you needed was a power supply , a RS232 terminal , a 6801 chip and a few passive components and you had a functional microprocessor . The 6801 had a monitor program in ROM and you could write programs in machine language . The programs where writen in hex .

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