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
Best or worst of ideas?
Re: Best or worst of ideas?
Here's a blog about Raspberry PI ZX81.
Re: Best or worst of ideas?
That looks like a good starting point - thanks for the link
Trevor
Trevor
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Re: Best or worst of ideas?
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
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
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert 
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp


There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb

Spring approaching...
Re: Best or worst of ideas?
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.
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.
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Re: Best or worst of ideas?
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
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
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert 
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp


There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb

Spring approaching...