Build your own computer , Yes it's DIY time

Spotted some time ago, Elektor is late to the party.

Nothing to hold him back. Go Geek, go!!

Not in the same league but back in 1963-4 I wrote the engineering manual for the English Electric KDN2 computer. Similar spec, same size and similar price (but 40,000 1963 pounds). By the time I'd finished I could have told you the function of each transistor, resistor, magnetic core and relay (yes relay). Then silicon chips came along and I don't think that was possible any more.

Another Dave

A teeny bit obsessive, but I can think of much more useless things that people do. And it might well have some usefullness for teaching. Well done keeping the power down to 500W though.

Hmm, reminds me of a transistor version of colossus. I think the latter probably gets a lot hotter having seen it up close. Strange idea. Brian

I built the zx81 from a kit when I could see. It was quite boring having lots of diodes and the same value resistors all over the place. Some years later I saw a russian copy of a Spectrum. Although it used a clone of the z80, the logic array was made from discreet logic chips and used up most of a pcb twice as big as a normal Spectrum! Bit power hungry also. I bet the person who reverse engineered ten the logic array was almost mad by the end of that job! Brian

I would have said he was mad before he started the job.

When I watched the video, I was surprised how normal he appears. He even smiled at the end.

And many have smiled back at him. I applaud.

Now I have a fascinating hobby of collecting pizza delivery leaflets put through the door. Completely useless occupation for which I'll surely get a certificate ...

I don't have the details of colossus, but I imagine the current one is several orders of magnitude more powerful.

Years ago when my old company opened an office in Bulgaria some of my colleagues went over to see the local staff and heard how one local in a former job had to reverse engineer a chip by a set up which they had rigged where they listened for various tones to determined what was happening in the chip. I think it was a processor chip which sounds a bit ambitious but maybe that's my memory playing tricks.

The story seemed too far fetched to be false and anyway it was just idle chat rather than an important achievment used to persuade the London office over some matter.

If by that you mean the Colossus rebuild...my understanding is that it is built from original components.

We built a few of the Slinclair projects in an electronics class at College, one of which being the ZX81. Two of them worked first time and I spent the next term repairing (assembling correctly) all the others. ;-)

The most compact kit was the Micromatic radio and the thing that consumed the most batteries, the Cambridge calculator. ;-)

No, a mate built the Sinclair 'Black Watch' kit and that may have beaten the calculator on battery consumption. ;-)

Cheers, T i m

No, I mean the transistor one currently being discussed!

How long have we had ECU equipped cars now, 30 ish years?

A mate at work I recall was horrified at the cost of getting a faulty one replaced on his Renault 5 Turbo, while talking about it another work colleague said wish I'd known as I know a chap who repairs ECUs. He went on to say he did it by "listening to them". I did not stay interested enough to bother if this was true or not but it sounds as if he was doing a similar thing.

G.Harman

I still have a cambridge calculator. Not used.

I know someone who does a lot of stuff with ECUs (as does a friend of his).

He was describing some car made in the USA about 30 years ago, whose ECU was in a metal box in the boot (box slightly corroded by acid from the battery next to it). Two (or more, I forget) big boards samdwiched together; didn't dare interfere. Apparently one of the signals needed for starting was too weak to get to the front of the car reliably. They ended up cobbling together a buffer circuit for this one signal (luckily it wasn't too time critical). Before that, they were doing something strange, plugging in a PSU to the front of the car just for starting.

Does it still work?

Cheers, T i m

I seem to have had that hobby forced on me by an apparently never-ending stream of fast-food start-ups from the cheaper end of my local high street.

Fortunately my paper recycling box lives near my front door so my collection turns over quite rapidly.

Mine did the last time I tried it but that was a good few years ago and I'm not sure where it is now. I very much doubt I'd have chucked it out as it worked.