Sinclair ZX80 / ZX81 / Z88 Forums

I'm after some opinions.

I've got a spare '81 case, a new (2014) keyboard, and a couple of knackered motherboards. I bought the latest "dead" machine from Ebay as a case for my Minstrel 3, but between buying it and it arriving, I decided to repurpose a slightly less knackered '81 I had from years ago (keyboard issues - hence new keyboard which never worked; I decided on resistor array, bought some replacements and never fitted them) - however...

I'm currently a bit narked with the Minstrel (see other threads), and while I'm aiming to keep it, it's currently likely to be put in a box in a cupboard for a while.

I have a spare case (the one bought from Ebay). I also have a case that I 3d printed - looks ok; I gave it a bit of "sparkle" by using black filament with gold flecks. It too has a nice new keyboard, but is currently home to my non-working keyboard'd motherboard. At some point I'll get the keyboard working again (or I'd like to think I will).

Where is this going I hear you mutter (it's not worth shouting)..

So - I want a working ZX81 (modern - no rampack, works with modern screen etc) - or equivalent.

I've seen some articles about using a Pi (of which I have many) as an emulator. Reality is I can build a pi-zero in a zx case; it would probably be a tweaked 3d printed version of the case with Pi friendly ports and mounting points. It would obviously have the emulation software - and using some of the articles I've seen I'd also use the standard ZX keyboard.

Is it worth it - what's the general consensus?

Trevor

Here's a blog about Raspberry PI ZX81.

That looks like a good starting point - thanks for the link

Trevor

Ahh, now I will be a bit biased. I have a LCD TV that works both with a composite modified Zeddy and with the RF/UHF TV output.

I have modified an issue 1 ZX81 board with a 32k byte SRAM chip (giving an extra 16k bytes of RAM available to BASIC).

So I use (mostly) original hardware. But I also like constructing (and sometimes modifying) kits. So have a number of ZX80/ZX81 ‘clones’ / compatible boards.

So we get to the real question, what do you actually want? Original working hardware. A modern version. A hardware ‘emulation’ (FPGA) or a software emulation (PC or Rasp.Pi)?

Or is it anything that works?

If you do want ‘real’ / original hardware, do you have, or are you willing to learn to service / fix / repair or modify / upgrade it?

Mark

There's no hard and fast answer;

I've got a pair of "standard" ZX81's. In the coming days, one will be getting the internal Ram upgrade (based on the info on Dave C's blog). It will - eventually - get the composite mod too.

As you've seen on other postings, I've got a Minstrel 3 - which hopefully will soon be fully functional

What I'm after from this post is a "fuss free" option; something "plug and play". I know the easiest option is probably an emulator, but it lacks the feel of the real thing, hence wanting to put something in a proper looking case - even if I print it myself in lurid colours (a psychadelic coloured case IS a real option).

Yes, I'd like to fix/service/upgrade/repair the hardware, but I also don't want to lose sight of just having a bit of fun with it at the same time.

There are a number of guides on modifying a ZX81 to perform an internal RAM upgrade.

I detail how I did it on an issue 1 board here. But there are other guides, Retrotechie showed how he did it on an issue 3 board.

Mark