New Caps And RAM Save Another Poly-1

1980s American teenagers, if they were lucky enough to attend a school with a computer lab, would have sat down in front of Apple IIs or maybe Commodore VIC20s. Similarly, their British cousins had BBC Micros. Solid and educational machines with all sorts of wholesome software, which of course the kids absolutely preferred to run in preference to playing computer games.

New Zealanders, at least a few of them, had the Poly-1. A footnote in the 8-bit microcomputer story, this was a home-grown computer with a built-in monitor clad in a futuristic one-piece plastic shell. Non-Kiwis never had the chance to encounter its 6809 processor and 64k of RAM, the global computer business being too great a challenge for a small New Zealand technology company, especially one whose government support had evaporated.

Decades after the end of Poly-1 production, some survive in the hands of enthusiasts. [Terry Stewart] has two of them, and has posted details of how he brought life back to one that was dead on arrival. It’s a story first of a failed electrolytic capacitor and tricky-to-dismantle PSU design, then of an almost-working computer whose random crashes were eventually traced to a faulty RAM chip. It seems swapping out that quantity of DIL RAM chips is rather tedious, and of course it had to be the final chip in the final bank that exhibited the problem.

Meanwhile it’s interesting to see the design of this unusual machine. A linear power supply contrasts with the switcher you’d have found in an Apple II at the time, and the motherboard is a huge affair. it’s easy to see why this was a relatively expensive machine.

We brought you [Terry]’s first Poly-1 last year, but so far he’s the only owner whose machine we’ve seen. More mainstream 8-bit machines are a common sight here, so for something else a bit esoteric read our coverage of home computers behind the Iron Curtain, and its companion piece on peripherals behind the Iron Curtain.

[via Hacker News]

18 thoughts on “New Caps And RAM Save Another Poly-1

  1. “Non-Kiwis never had the chance to encounter its 6809 processor and 64k of RAM”. To be exact you should write “to encounter the POLY-1” because we met the 6809 processor in Radio-Shack Color computer. I had a COCO2 and was running OS9 from 2 floppy drives.

    1. The TRS-80 Color Computer was a great little machine. I spent many happy hours programming its 6809e in assembly using EDTASM+. There was a nice Pascal compiler (true compilation, not P-code) and a real C compiler.

    1. The toilet seat iBooks had a useful thing with their handle. Why hasn’t any laptop or notebook since had a built in handle? Bag makers own tons of stock in computer companies?

      1. Wow, I expected to find a few models for a laptop handle/bumper frame on thingiverse… nothing.
        Not sure how to wrap around back where the screen folds up and down but that is where I would want the handle.
        Truthfully I would love a big burly ABS case for my tablet too where I could put the microUSB keyboard form it’s current folio and a USB nipple mouse made from a digispark(is that an IBM patent like the Think-Light?). It is just too easy to break the screen otherwise, though I think some o-ring qr latches so it can go naked for reading ebooks at home.
        Further off topic does anyone know a trick to get a gpio to hack for a software fn key on/off keyboard light onto a laptop? Mine has under-key lights but wife’s doesn’t.

      2. Because laptops are mostly very thin plastic and have very little tensile strength. They would simply tear apart if they were subjected to the G forces that are likely should they have a handle.

    1. It was the Research Machine 380Z that sparked my interest in computing. Coding in BASIC after school, friend would type with one hand, shovel cake with the other.
      We emptied a handful of crumbs from the keyboard before we had to return the Computer for the next school to use for a month.

  2. There is an easier way to test RAM that works most of the time.

    Get a know good RAM chip and bend the pins in a little then (with power off) press it over the first chip in the RAM bank and power on. Then remove the power and then the known good chip and repeat on the next chip in the bank until it works. When it works then the dead chip is the one that the know good chip is over.

    This can sometimes (rarely) damage the know good chip and it doesn’t work 100% of the time but when it does work it can save a great deal of time especially with soldered in RAM chips.

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