Old Stuff (original) (raw)

Sun 10/7/2007

Which computer qualifies as the first "personal computer" depends upon how you define what a personal computer is, but a strong contender has to be theKenbak-1Introduced in 1971, over three years before the MITS Altair, it is a unique and interesting machine. Only 40 Kenbaks were sold and probably far fewer remain in existence today.The Computer Museum of Nova Scotiaowns 7 of them, which has to be the largest single collection of Kenbaks and may even represent the majority of remaining machines. My chances of ever finding an original one are essentially nil; they occasionally show up on sites like eBay every few years, but when they do they fetch prices over $10,000.

But all is not lost.Grant Stocklyhas just released an amazingly accuratereproductionof the Kenbak-1 in kit form. Similar in spirit to hisAltair 8800 kit, it is about as close as you can get to an original Kenbak without actually owning one. I ordered one a while ago and it arrived today. I'll add more pictures as the build progresses.

The kit arrived. Grant had the back signed by John Blankenbaker, the designer of the original machine. A nice touch.

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Oops. I should really double check my socket placement before soldering them. Oh well, rather than desoldering the socket, I just cut the middle out of it, split another into two and did this. No one will ever know.

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Resistors are done. Capacitors, diodes, and transistors took another hour or so.

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The front panel showed fingerprints quite badly. Washing in a mild detergent followed by a couple of coats of lacquer fixed that.

The keyswitches in the original kenbak were glued into place. Grant used switches that can snap in, but then the buttons are a little too high. I decided to make a switch carrier that holds the buttons at the right height but uses screws instead of glue. The screw heads are non-standard, but then so are the colored keycaps.

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We're in the home stretch now. I just need to crimp connectors onto those 27 wires and then I'll be able to start testing.

Well, it's close. I traced one problem with the front panel to a bad chip; now front panel operations are perfect, but it won't run any programs. Still checking. I don't know what I'd do without a logic analyzer to see what's going on.

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[ ](view.php?ps=Old Computers&pn=4&f=w-kenbak%5Ftesting.jpg)

There's the culprit, one missed solder joint. Finally, it's working beautifully and it can join its cousin, another of Grant's magnificent kits..

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