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#zx81 — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #zx81, aggregated by home.social.

  1. In the future, you will have uninterrupted access to computing for one single payment of $149.95, indefinitely.

    #zx81 #sinclair #retrocomputing

  2. In the future, you will have uninterrupted access to computing for one single payment of $149.95, indefinitely.

    #zx81 #sinclair #retrocomputing

  3. In the future, you will have uninterrupted access to computing for one single payment of $149.95, indefinitely.

    #zx81 #sinclair #retrocomputing

  4. In the future, you will have uninterrupted access to computing for one single payment of $149.95, indefinitely.

    #zx81 #sinclair #retrocomputing

  5. In the future, you will have uninterrupted access to computing for one single payment of $149.95, indefinitely.

    #zx81 #sinclair #retrocomputing

  6. Forgot to add the finished assembled shot...
    PCB rebuild project successful.
    Unregulated so actually showing 12v with no load. 🤣
    I'll actually use a modern switched 9v for my ZX, but I wanted to get the original supply back working again.
    #retrocomputing #zx81

  7. Next step replace the ancient 7405 voltage regulator with a modern decent one.
    But I'm on the fence whether to do anything else to this. I think I'd prefer to keep it pristine(ish).
    It feels like these initial mods are in keeping/acceptable to the age of the zx:
    * connecting to an analogue TV is impractical now, so a composite upgrade feels ok
    * the keyboard membrane was toast (cracked and disintegrating) - the replacement looks identical
    * and the power regulator can be updated on the same footprint to solve the power/heat issues.
    I *could* upgrade the internal ram to remove the need for the external ram cartridge and fit a modern FPGA ULA to fix the video quality and add features like 32k support and high res graphics..... but that feels wrong somehow wrong and too much. 🤔
    #retrocomputing #zx81

  8. Ok... back porch composite mod fitted, still no joy with desktop LCD... But YAY the 4k with video processor can show it! Ooooh.
    #zx81

  9. Shit. No back porch on this "issue 1" board.... Can't do a quick and dirty composite mod. 🙄
    Little projects always turn into big projects.
    #zx81

  10. Um oh, ok. I think that PSU's had it. ☹️
    Power diodes now appear to be two piece components. 🙄
    Just for completeness I might strip it down and (carefully) see if the windings are ok and if I've got any chunky 1N diodes I can try.
    #zx81 #retrocomputing

  11. Right, and so it begins... first job, add a composite video mod, then I'll need to decide how to (re)attach the keyboard. The flex connector looks rough/cracked/fragile.
    Will probably replace with a length of ribbon cable but not sure I want to try to desolder the PCB connector given the age of the foil tracks.
    #retrocomputing #zx81

  12. Excellent little review of Zevious Seven in Retro Magazine World issue 54! 🕹️

    There is also a great feature on the ZX81, a review of ALTAIRIS, and much more.

    Mag available here: retromagazine.net/getrm.php?id

    #RetroMagazineWorld #Homebrew #ZX81 #RetroGaming

  13. So, it turns out that when you do a composite video mod on a vintage computer, your TV can no longer tune into it. I mean who would have thought that changing the mode of video output would change the mode of video output!?

    I've just spent the last half-hour trying to work out why a video mod for a #ZX81 had apparently killed it, including reversing the mod to see what had changed... doh!

    What's the error code for "User error - replace user" :)

    #MakerFail #RetroComputing

  14. En faisant du rangement, je retombe sur le manuel de l’Acorn ATOM, mon 2e ordinateur après le #ZX81. C’est avec lui que j’ai appris l’assembleur #6502.

    “This manual explains how to connect up the ATOM, and how to program it in BASIC or Assembler”.

    Fun fact: l’entreprise Acorn a évoluée en « Acorn RISC Machines », maintenant connue sous le nom d’ARM, qui équipe probablement votre smartphone.

    #retrocomputing

  15. In July, I had the pleasure of being a guest on the Timex Sinclair group, talking about #Zevious, #TutTut and other projects. Thanks for having me! #ZX81
    youtu.be/E7xjBM8rvIo?si=6ueWUt

  16. (pictures to follow)
    So I've been clearing through my parents attic, digging out old stuff.... and I've found a ZX81 😍, BBC Master 🤓 and I *think* I've got an SC/MPuter too! 😲
    Couldn't find the old AtariST, Dragon32 or BBC Model B though. 😟 (I was actually looking for the Beeb)
    Not sure whether to resurrect the two TRS80's (model I and II) they looked a bit worse for wear.
    #retrocomputing #zx81 #bbcmicro

  17. Back in the saddle! Finished up the last part of my Timex Sinclair 1000 restoration project. The last phase is a memory upgrade from 2K to 16K. First, I popped off the existing chip to make way for the upgrade.

    #ZX81 #TS1000 #retrocomputing

  18. Did some research on the TS1000's composite video issue - discovered that some composite mods will overdrive the output a bit, causing the washed out image.

    The solution was to drop an additional resistor in-line between the composite mod board and the RCA jack. I used a 47Ω resistor since that was a value I had handy, and it worked!

    #ZX81 #TS1000 #retrocomputing

  19. More progress on the TS1000 tonight - got the composite mod wired in and tested. It worked, but I was disappointed with the amount of noise in the video.

    Went ahead with a recap and voltage regulator replacement as planned, and threw some heat sinks on the ULA for good measure. Doing so helped, although video was still really washed out.

    #ZX81 #TS1000 #retrocomputing

  20. Finally got this Timex Sinclair 1000 project far enough along that I have something to show.

    It's a PCB/rework of the ZX-Wespi-mi (the non-vga version). The ZX-Wespi is an ESP32 mod that you connect to your TS-1000/ZX-81.

    You can send programs to it over WiFi using your browser.

    My project combines the components and wiring into a single PCB - it's the Wespi Hat 🙂

    Since it's going to be on a TS-1000, I decided that I'd mount it externally. The TS-1000 has RF shielding spray coating the interior and I'm not sure how that would effect the signal.

    This first version works but has some problems that I noticed once I was assembling, so I've already redesigned the PCB to address those.

    I also want to rework the wiring, and the case design needs a bit of a tweak too. This will be an evolving project 😃 #RetroComputing #Electronics #ZX81 #TimexSinclair #Sinclair #TS1000 #WespiHat #VintageComputing