ZX21 Project ZX81 Replacement PCB

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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blittled
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Re: ZX21 Project ZX81 Replacement PCB

Post by blittled »

Can't wait to see how it works! :D . I'm going to start looking into replacement ULAs. I don't want to cannibalize the ZX81s I have to build another one. I know this will be opensource so it'll be up to me to find a pcb fab house and send the gerbers to them.... unless someone makes a run of pcbs and sells them. [Hint]
2X Timex Sinclair 1000, ZX81, ZX80Core, 5X 16K Ram Pack, ZXBlast, ZX P file to Ear Input Signal Converter, Elf II
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

I am looking forward to getting it going. I may have some spare PCBs when I have finished. It is called the ZX21 for a reason I am not expecting to have it finished this year but I am hopeful for next year.
FordP (Simon Ellwood)
Time is an illusion. Lunchtime, doubly so!
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1024MAK
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Re: ZX21 Project ZX81 Replacement PCB

Post by 1024MAK »

Which bright spark is gonna point out that there are less than twelve tinkering days to the new year, ahh, that would be me then :lol:

If there are any spare PCBs, I would like one please.

Mark
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XavSnap
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Re: ZX21 Project ZX81 Replacement PCB

Post by XavSnap »

Kicad Project:
ZX21_1.jpg


ZX21.jpg


ZX21_2.jpg
Xavier
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

XavSnap wrote: Sat Dec 19, 2020 5:07 pm Kicad Project:
Thanks for the screenshots.

When I get time I want to get the 3D models right on most of the parts. I hope if anybody else has ideas they can start making use of the ZX21 project.
FordP (Simon Ellwood)
Time is an illusion. Lunchtime, doubly so!
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

IMG_20201220_162334.jpg
I am still missing some bits.
FordP (Simon Ellwood)
Time is an illusion. Lunchtime, doubly so!
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1024MAK
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Re: ZX21 Project ZX81 Replacement PCB

Post by 1024MAK »

Still, it’s coming along :D

Mark
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

I have added quite a few more bits since that picture and I have ordered the remaining passives from Farnell. £50 but I have ordered plenty for projects for a few years (of those values).

Oh and I spotted in time I had two RAM chips and no ROM chip above, Doh.
FordP (Simon Ellwood)
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

IMG_20201224_151233.jpg
All the bits for a standard ZX81 are now it fitted. It is powered on and the clock is ticking.

On to troubleshooting now.
FordP (Simon Ellwood)
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fordp2002
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Re: ZX21 Project ZX81 Replacement PCB

Post by fordp2002 »

IMG_20201224_154358.jpg
Massive progress, it somewhat works.
Some keys on the keyboard are not working yet.
FordP (Simon Ellwood)
Time is an illusion. Lunchtime, doubly so!
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