Another find in my attic, a ZX81 - UK Vintage Radio Repair and Restoration Discussion Forum

Buzby123 · 12th Oct 2020, 12:30 pm

Searching for a tray of switches I know I've got somewhere, I found what looks like a ZX81. Whoopee !

But when I opened the box look what I found ....

MrBungle · 12th Oct 2020, 12:35 pm

Oh wow. Unbuilt as well!

I wish I had your attic

SiriusHardware · 12th Oct 2020, 1:58 pm

I owned a ZX81 kit, briefly. But then I built it. (This was back in 1981).

Have you owned that from new? If so, why did it never get built?

Paradoxically, you may find that the keyboard membrane needs to be replaced. They are all getting to the age where the 'tails' which connect to the PCB have started to go very brittle.

60 oldjohn · 12th Oct 2020, 2:34 pm

Wow! would you like to swap your kit for a built one?

please answer by PM. Seriously has yours got the raised ZX81 moulding painted red? I suspect it may be black denoting it as a kit, am I correct? I asked this question years back It would be nice to get a definitive answer.

Buzby123 · 12th Oct 2020, 2:35 pm

No, I didn't own it from new.

I bought it on eBay many years ago, back when eBay was a more friendly place. At that time you could communicate with other bidders, and I think that's how I found it.

Anyway, it's gone back in the attic. I've got to get my MK14 running before I embark on any more projects.

Edit : I've just checked, the raised ZX81 text is red. I'd never heard of a different colour for kit items. My original ZX81, which I did build from a kit, had red text. I specifically remember thinking at the time 'Why was this text coloured, but not the Sinclair name ?'.

Somewhere I should have two other ZX81s, my original built kit, and another I was given a few years later.

I'm not going searching for them now, there's too many distractions in the attic.

Dave Moll · 12th Oct 2020, 2:39 pm

Ironically, assembling the kit will probably devalue it!

SiriusHardware · 12th Oct 2020, 3:12 pm

Mine (originally a kit) had raised red 'ZX81', but as it is so prominent it is the first part of the finish which starts to look shabby on a used machine. At that point people often scrub the rest of the red off to make it look tidier.

12th Oct 2020, 6:02 pm

Those were the days, getting one track twixt two DIL pins on a PCB. If it was mine I would build it with IC sockets.

Timbucus · 12th Oct 2020, 10:08 pm

Nice find - Too nice to build these days... that is one kit that needs to stay unmade. In that printed box it is likely to be the later ones as there were a load of kits available as someone bought the remaining ones from a warehouse as they were intended for schools or similar if I remember.

I do remember the weeks waiting for my kit to come back from Sinclair with only the manual to read - turns out it wasn't my fault it didn't work the Z80 was faulty. Their diagnostic technique on the phone was to ask if I could touch the ULA - when I said no it was too hot they said that means its working OK.... Sadly my ULA recently died in my original so I swapped it for the new modern vLA81 https://vdrivezx.com/vla81/ which has the benefit of a back porch so I can actually see it on my TV...

Buzby123 · 12th Oct 2020, 11:01 pm

Quote:

Originally Posted by Timbucus

... Sadly my ULA recently died in my original so I swapped it for the new modern vLA81 https://vdrivezx.com/vla81/ which has the benefit of a back porch so I can actually see it on my TV ...

That's a cool device !.

I often read that the ULA was prone to failure, but it never happened to mine ( well, not yet, but who knows if they will work when I find them. )

How many ZX81s got chucked in the bin when the ULA stopped working, or the owners got a 'too modern' telly ?.

On these forums I have seen that there are skilled enthusiasts still maintaining wireless sets that are over a hundred years old.

Will there be a similar group in fifty years time looking after our MK14s and ZX80/81s?.

SiriusHardware · 12th Oct 2020, 11:13 pm

If there are, they will also be keeping alive analogue TVs, cassette recorders and all the other life support paraphernalia which are needed in order to actually use them. I already keep a little 1970s black and white portable TV in running order for my ZX81s, etc.

I actually think that after we are gone there will be very few people who value them or know what they are. Right now we are at the peak of a golden age of people who remember their first forays into computers in the 1970s / early 80s and probably now have the money to buy the machines they couldn't afford when they were contemporary, plus the time to mess on with them if they are fortunate enough to have retired.

12th Oct 2020, 12:30 pm	#1
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 653	Another find in my attic, a ZX81 Searching for a tray of switches I know I've got somewhere, I found what looks like a ZX81. Whoopee ! But when I opened the box look what I found .... Attached Thumbnails Last edited by Buzby123; 12th Oct 2020 at 12:37 pm.

12th Oct 2020, 12:35 pm	#2
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Another find in my attic, a ZX81 Oh wow. Unbuilt as well! I wish I had your attic

12th Oct 2020, 1:58 pm	#3
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,548	Re: Another find in my attic, a ZX81 I owned a ZX81 kit, briefly. But then I built it. (This was back in 1981). Have you owned that from new? If so, why did it never get built? Paradoxically, you may find that the keyboard membrane needs to be replaced. They are all getting to the age where the 'tails' which connect to the PCB have started to go very brittle.

12th Oct 2020, 2:34 pm	#4
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,985	Re: Another find in my attic, a ZX81 Wow! would you like to swap your kit for a built one? please answer by PM. Seriously has yours got the raised ZX81 moulding painted red? I suspect it may be black denoting it as a kit, am I correct? I asked this question years back It would be nice to get a definitive answer. __________________ My favourite text message "I'll be there in five minutes, if not read again"

12th Oct 2020, 2:35 pm	#5
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 653	Re: Another find in my attic, a ZX81 No, I didn't own it from new. I bought it on eBay many years ago, back when eBay was a more friendly place. At that time you could communicate with other bidders, and I think that's how I found it. Anyway, it's gone back in the attic. I've got to get my MK14 running before I embark on any more projects. Edit : I've just checked, the raised ZX81 text is red. I'd never heard of a different colour for kit items. My original ZX81, which I did build from a kit, had red text. I specifically remember thinking at the time 'Why was this text coloured, but not the Sinclair name ?'. Somewhere I should have two other ZX81s, my original built kit, and another I was given a few years later. I'm not going searching for them now, there's too many distractions in the attic. Last edited by Buzby123; 12th Oct 2020 at 2:49 pm.

12th Oct 2020, 2:39 pm	#6
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,127	Re: Another find in my attic, a ZX81 Ironically, assembling the kit will probably devalue it! __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

12th Oct 2020, 3:12 pm	#7
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,548	Re: Another find in my attic, a ZX81 Mine (originally a kit) had raised red 'ZX81', but as it is so prominent it is the first part of the finish which starts to look shabby on a used machine. At that point people often scrub the rest of the red off to make it look tidier.

12th Oct 2020, 6:02 pm	#8
Guest Guest Posts: n/a	Re: Another find in my attic, a ZX81 Those were the days, getting one track twixt two DIL pins on a PCB. If it was mine I would build it with IC sockets.

12th Oct 2020, 10:08 pm	#9
Timbucus Octode Join Date: Mar 2019 Location: Barry, Vale of Glamorgan, Wales, UK. Posts: 1,363	Re: Another find in my attic, a ZX81 Nice find - Too nice to build these days... that is one kit that needs to stay unmade. In that printed box it is likely to be the later ones as there were a load of kits available as someone bought the remaining ones from a warehouse as they were intended for schools or similar if I remember. I do remember the weeks waiting for my kit to come back from Sinclair with only the manual to read - turns out it wasn't my fault it didn't work the Z80 was faulty. Their diagnostic technique on the phone was to ask if I could touch the ULA - when I said no it was too hot they said that means its working OK.... Sadly my ULA recently died in my original so I swapped it for the new modern vLA81 https://vdrivezx.com/vla81/ which has the benefit of a back porch so I can actually see it on my TV... Last edited by Timbucus; 12th Oct 2020 at 10:09 pm. Reason: correct typo

12th Oct 2020, 11:13 pm	#11
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,548	Re: Another find in my attic, a ZX81 If there are, they will also be keeping alive analogue TVs, cassette recorders and all the other life support paraphernalia which are needed in order to actually use them. I already keep a little 1970s black and white portable TV in running order for my ZX81s, etc. I actually think that after we are gone there will be very few people who value them or know what they are. Right now we are at the peak of a golden age of people who remember their first forays into computers in the 1970s / early 80s and probably now have the money to buy the machines they couldn't afford when they were contemporary, plus the time to mess on with them if they are fortunate enough to have retired.