ZX81 ULA

ZX80 / ZX81 hardware and software offered for sale or swapping
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Andy Rea
Posts: 1500
Joined: Fri May 09, 2008 2:48 pm
Location: notts UK

Re: ZX81 ULA

Post by Andy Rea » Tue Aug 14, 2018 6:29 pm

McKlaud wrote:
Tue Aug 14, 2018 12:51 am
Andy, it looks like you have a production line in the back garden ;) Keep going as the demand is there.

BTW finally I fitted one of your ULAs to my dead Zeddy's board and it works like a charm.
Well i have a few pcb's :lol: to keep me going, while people still buy i'll still make... Thanks for the feedback, help to make it feel worthwhile.

Regards Andy
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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RetroTechie
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Location: Hengelo, NL
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Re: ZX81 ULA

Post by RetroTechie » Wed Aug 15, 2018 7:27 am

I wonder how long original ULA's would stay in working order if just stored under normal (+/- room temperature, not too dry or moist air, no direct sunlight etc). Let's say, starting with little used or New Old Stock parts. Maybe power up once or twice a year (under carefully controlled conditions) to check if still working.

Verdict on that is still out on that for IC's in general. IC's only exist since the late 50's, early 60's or so. And some of the very earliest IC's ever made are known to be still working fine (especially well-built IC's in ceramic packages etc). But Sinclair ULA's are not like military-spec, hermetically sealed ceramic package. And not full custom but gate array + customer defined interconnect layer. Similar but not the same as a mass-produced single purpose IC. :? Sealing between external pins and internal silicon die, bond wires etc may not be 100%. Or plastic used may allow gasses/pollutants from outside world to leak in. Veeeerrry little, veeeerrryy slow of course, but still some, and leaked in molecules doing their destructive job. Not to mention high-energy cosmic radiation, or whatever else may attack / degrade the inside of IC's (let's assume ESD precautions are adequate).

40 years? 50 years? 60+? Will they die en masse after a certain age? Or will there be a very 'long tail' with some specimens surviving say, a century or more?

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: ZX81 ULA

Post by 1024MAK » Wed Aug 15, 2018 3:08 pm

And just as interesting as a question, will the much higher integrated, much smaller process silicon chips last longer than the older generations of chips?

So, will FPGA chips running versions of our favourite 1980s computers survive as long as the the actual 1980s computers? Will ZX80's last longer than ZX81's?

Mark

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

Re: ZX81 ULA

Post by Andy Rea » Thu Aug 16, 2018 5:52 pm

if kept in good conditions, then they will i expect outlast us so it will be the next generations problem :lol:

I wonder if in say 30 or 40 years time, people will be setting up Iphone 10 forums wondering how they are going to get parts to fix up that once faithful companion :mrgreen:

regards Anduy
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

dquadros
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Joined: Mon Aug 27, 2018 2:12 pm

Re: ZX81 ULA

Post by dquadros » Mon Aug 27, 2018 10:14 pm

Waiting for the next batch...

Daniel

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Andy Rea
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Location: notts UK

Re: ZX81 ULA

Post by Andy Rea » Tue Aug 28, 2018 7:02 pm

dquadros wrote:
Mon Aug 27, 2018 10:14 pm
Waiting for the next batch...

Daniel
starting some tonight :)

regards Andy
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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