"Different" ZX81's

Discussions about Sinclair ZX80 and ZX81 Hardware
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sirmorris
Posts: 2782
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Location: oxon, uk

Re: "Different" ZX81's

Post by sirmorris » Sat Jul 22, 2017 9:46 am

gammaray wrote:
Fri Jul 21, 2017 11:45 pm
Now the obvious question is will you make a custom unit that has a switch for choosing the power supply circuit...?
It should certainly be possible but it may not be pretty ;) Is that a commission or a rhetorical question? :)
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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gammaray
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Location: Texas

Re: "Different" ZX81's

Post by gammaray » Sat Jul 22, 2017 10:06 pm

I have a crazy idea about making improvements that are compatible with stock hard/soft-ware switchable.

I am getting the idea I may need to get the V2 zpand and was interested in making it battery powered with LCD screen so the need may be there.,.Ill get back with you.


Twisted threads... this should go with the K2 thread...
The answer is yes.

Wait I have my own project I was suppose to do the same with. I'll shutup now (but secretly wish for someone to take up the task...)

Did I just type what I was thinking and press enter?
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

Lardo Boffin
Posts: 701
Joined: Sat Nov 26, 2016 2:42 am

Re: "Different" ZX81's

Post by Lardo Boffin » Wed Aug 23, 2017 10:45 pm

A nice working issue three that came in a new sleeve type box.

Looks like they could not be bothered to fill the vias with solder on this one!

IMG_6725.JPG
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Anyone know why some of the issue threes have an extra capacitor down by the 7805?
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

Lardo Boffin
Posts: 701
Joined: Sat Nov 26, 2016 2:42 am

Re: "Different" ZX81's

Post by Lardo Boffin » Wed Aug 23, 2017 11:06 pm

A working issue one that came in a brown postal box.

IMG_6726.JPG
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ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

Lardo Boffin
Posts: 701
Joined: Sat Nov 26, 2016 2:42 am

Re: "Different" ZX81's

Post by Lardo Boffin » Wed Aug 23, 2017 11:13 pm

And a not working (not booting to the K, just a white screen, not swapped the ULA yet) early issue one. This one came with the ZX80 PSU that is minus the jack plug.

Amusingly this one was sold as an un-used kit! That was 'probably never used, ever!' I assume this was because the modulator is missing? :shock:

Also someone has attached wires underneath - possible a battery mod?

The ROM looks like it could be a bugged version judging by the number. Will put it in another zeddy and find out.

Regardless it was cheap, boxed and the case the zeddy is in is rather good! As is the very good condition issue one manual.

IMG_6724.JPG
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ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

Lardo Boffin
Posts: 701
Joined: Sat Nov 26, 2016 2:42 am

Re: "Different" ZX81's

Post by Lardo Boffin » Fri Aug 25, 2017 12:05 pm

And here we have a truly different ZX81.... Well, kind of.

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IMG_6729.JPG
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All the way from the US of A!
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

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1024MAK
Posts: 1863
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: "Different" ZX81's

Post by 1024MAK » Fri Aug 25, 2017 1:16 pm

Nice 8-)
Have you figured out how to get a video signal displayed yet?
If yes, does it work?

Mark

Lardo Boffin
Posts: 701
Joined: Sat Nov 26, 2016 2:42 am

Re: "Different" ZX81's

Post by Lardo Boffin » Sat Sep 09, 2017 10:34 pm

This one seems to be missing some bits...


Ohhh shiny!
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IMG_6892.JPG
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Ah here they are!
IMG_6893.JPG
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Looks like a few evenings of very anxious soldering!
ZX81 iss 1 (bugged ROM, kludge fix, normal, kit)
Iss 3 with ZXVid, another in nearly perfect box
TS 1000 iss 3, ZXPand AY, ZX8-CCB & ZX-KDLX
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Spectrum 48k
Toastrack + DIVMMC future

Moggy
Posts: 1553
Joined: Wed Jun 18, 2008 2:00 pm

Re: "Different" ZX81's

Post by Moggy » Sat Sep 09, 2017 11:24 pm

"LARDO STEP AWAY FROM THE SOLDERING IRON! :lol:

Serious face, when you hinted that you 're going to assemble this little beauty my heart sung, no display cabinet for this one build it and use it.

Nice one Lardo happy soldering. :D


Regards.

Moggy.

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Andy Rea
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Joined: Fri May 09, 2008 2:48 pm
Location: notts UK

Re: "Different" ZX81's

Post by Andy Rea » Sat Sep 09, 2017 11:30 pm

Build it.... would be a shame.to.let it rot unused :mrgreen:

I had a kit once.....
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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