Sunday, April 01, 2012

Timex Sinclair ZX81, My First Home Computer

I brought my Timex Sinclair ZX81 back from my visit out East.DSC01221
My dad bought it in 1982, It was $99.95!
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Tiny with a flat membrane keyboard.
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The 16K RAM pack. It has 1K onboard.
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The video cable, not a composite, but a UHF signal.
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I tried to use the adapter on the right with a cable, but it didn’t work. My EE on call suggested the impedance was wrong. So I soldered up this cable from a coax and an RCA plug.
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I think there’s probably a better shielded solution out there.
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Feeding it into an old ATI All-in-Wonder AGP card in a P4 box through the CATV jack.
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I had to play with the settings, pumping up both brightness and contrast.
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The ancient ATI software sucks. This actually looked a tiny bit better on screen. I think there’s a lot of noise in my system. But it’s legible. Here are some videos I captured:
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The confusing membrane keyboard. You try and figure it out.
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16K Ram pack installed.
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No output at all. Must be bad.
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I have some software!
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Wrap your head around this.
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I have reference material. The Z80 book was a birthday gift. I did a lot of PEEKing and POKEing.
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Why not open it up? Two slotted screws on one side, two Phillips on the other.
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Opened.
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Some insulating card stock.
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Other half.
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I don’t know what it is. Could just be fluff, but it could be from the capacitor.
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One board.
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The other. Connected with a ribbon cable.
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That fluff. What is it?
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Removed, it may not be anything. But maybe I’ll replace that cap? We’ll see, I want to do a little reading.
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This might be my new desktop wallpaper.

2 comments:

Diane Dew said...

My brother Scott built a computer from a RadioShack kit in the late 70's, when he was in high school. I remember that it used a cassette tape (for memory?). At the time, he wrote some programs that he sold to magazines - I was very impressed!

Nick Carter said...

You need to find copies of those magazines! Important history.