Help in resurrecting my ZX81

Discussions about Sinclair ZX80 and ZX81 Hardware
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mrtinb
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Yahoo Jippie Hurray Hurra Yeah!!!!

Post by mrtinb » Tue Jan 08, 2019 11:15 pm

Finally I got my ZX81 from Danish distributor to work again with Andy Rea's new ULA. :D :D :D

I found a second cut on the pcb from the destructive removal of the old ULA. So now there's 2 wires on the bottom of the pcb, and it works great, and a new transistor has been inserted where one was removed in the debug fase.

You can even see the inverse screen created by Andy's custom firmware.

Now off to bed. Tomorrow will bring new adventures with enabling of the ULA's M1NOT feature and maybe enabling of composite output.

Thanks again to everyone here helping me to resurrect this old friend. :D

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Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

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mrtinb
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Re: Help in resurrecting my ZX81

Post by mrtinb » Wed Jan 09, 2019 11:20 pm

And now a monitor is connected and M1NOT modification added temporarily with the white jumper wire

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Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

Moggy
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Re: Help in resurrecting my ZX81

Post by Moggy » Thu Jan 10, 2019 3:14 pm

Excellent work Martin. :geek:

Another one comes to life and thanks for reminding me about the inverse video I had forgotten about that. :oops:

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1024MAK
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Re: Help in resurrecting my ZX81

Post by 1024MAK » Thu Jan 10, 2019 8:22 pm

Good to hear that you have got your ZX81 working.

That board does look it has been through the wars though...

Mark

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mrtinb
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Re: Help in resurrecting my ZX81

Post by mrtinb » Thu Jan 10, 2019 10:28 pm

My old soldering iron was not easy on any boards
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

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