ZX81/TS1000/TS1500 Cleanup: Part 1 [TCE
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- Опубліковано 7 вер 2024
- I've been collecting bits & pieces over the years and have done some experiments to try to find the best overall improvements that could be made.
But ... surprise ... things have been left half-done, so it's about time I sorted out what I've got and fix up what I can.
I've got mostly Timex Sinclair TS1000s as these are quite plentiful and relatively cheap compared to ZX81s. I've also got a TS1500 which is a ZX81 (or TS1000) with 16KB of RAM in a ZX Spectrum case ... actually, I might have two ... just remembered a briefcase version ...
The main things I like to do:
[1] Convert TV modulator to composite (emitter follower)
[2] Replace the 7805 linear regulator with a modern switching equivalent
[3] Replace ULA with vLA81
[4] Upgrade RAM from 1KB (or 2KB in TS1000) to 16KB
[5] Replace the original 2364 with something else
[6] Replace the keyboard membrane if required
Replacement 2364 ROM:
store.go4retro...
github.com/Toy...
k1.spdns.de/Vi...
ZX-Key external keyboard:
www.zx81keyboa...
vLA81 ... excellent replacement ULA:
www.vretrodesi...
ZXpand+ joystick & SD interface:
www.sellmyretr...
Other ZX81/TS1000/TS1500 videos:
• Sinclair ZX81/TS1000/T...
![ZX81/TS1000/TS1500 Cleanup: Part 2 [TCE #0324]](http://i.ytimg.com/vi/cKFFo4kAyE4/mqdefault.jpg)
![ZX81/TS1000/TS1500 Cleanup: Part 2 [TCE #0324]](/img/tr.png)
You can never have enough of these wonderful machines. I fail the see the problem here.
Damn that's a lot of 81's, I can see they'd be easy to collect they are so cute and little. I like the look of the TS1500.The NZ fellow is Charley Ingley, he's doing god's work. I got a vLA82 off him.
They are very easy to accumulate ;) Charles is indeed a good fellow - I want to get a Microdrive just so I can get one of his cool replacements!
Wow, that’s a wonderful collection of the great little computer.
You initially think ... "membrane keyboard, pfft" ... but it's such a cool little design ... basically just four ICs and you have a computer that can run a power station ;)
ua-cam.com/video/tB6CC8UbJLU/v-deo.htmlsi=oFvCRiVebvEi4PPr
ya havent got enough bro!.. need more! ..interesting to see all the different colored boards n what not in them
That's a lot of tiny computers!
Imagine a Beowulf cluster of these (old /. reference).
Excellent video and collection. Thanks for sharing
Coincidentally, I finally got myself a ZX81 last month through a trade. I also designed my own keyboard replacement from scratch *WITH a real SPACE BAR*. I'm currently seeing if there’s interest in it before I send off to have the PCBs made.
I will take two please :)
Check out ZX81 Keyboard Adventures for ideas too ... they've also designed a case
www.zx81keyboardadventure.com/p/zx-key-support.html
i am game....tell me how to get one! :)
Hey Brett. Just a FYI. The VLA81 has a built-in composite mod. If dip switch 1 is off (default?) then the video signal is composite and terminated with 75ohm, ready to go. The VLA81 also supports the extra 16K in a 32K ram upgrade. Just need to run an extra wire from the VLA81 to the top address bit of the ram. You can configure where the 32K is mapped with either dip switches or code
Ahhh, I didn't realise! Thanks - I'm just doing a composite mod on the first one - I'll try the vLA81 only on the next one. And it's good to know about the 32KB support as well - I will definitely try that out! /Brett
I've seen z80's on Retro Lemon that have 32k of RAM on intended for the Spectrum that should *in theory* work just fine for a ZX81. It has a modern small package Z80 and upper 32k right in the same footprint as the Z80. Only problem is that it's the top 32k. Probably great for a system with 16k of RAM built in, but troublesome on a 1 or 2k machine because you'll have a gap in the memory map between 4000h and 8000h
Interesting idea ... I guess one could try and do something similar for the ZX81 ... might be an interesting project. How does the 16KB external RAM pack work at the moment ... I assumed it disables the internal 1KB/2KB RAM via a signal ... ? /Brett
Jeez man how many old computers do you have there?!
Too many ... but it's been many years of collecting. Sometimes need to get multiple copies of a computer to try to get some rare optional part ... or because the three previous you bought "untested" don't work ... or you need another example to get spares from to get one "museum quality" one working. My "problem" is that I don't like to sell a computer if it's not working perfectly.
are any of those T1000 for sale?
Not at the moment, but I do plan to re-home them once I fix them. Hopefully!
@@Brfff my very first computer was a Timex Sinclair 1000.
How the hell did they manage to make a computer that outputs to TV, has a keyboard, and does Basic, in just 4 chips?? Even the TEC-1 that only has 7 segment displays, a hex keypad and no Basic took 9 chips!!
The ULA! Similar with the Speccy ... and the Soviet versions ... the Soviet/post-Soviet machines that used the Angstrem ULA have very few parts (cheap) ... but if the ULA fails, you're effed ... with the Speccy you can at least get a modern replacement! The Speccy clones using discrete chips would've cost more to produce but have at least a chance at being repaired ... if they have an issue at all