Lardo buys another zeddy

ZX80 / ZX81 hardware and software offered for sale or swapping
Lardo Boffin
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Re: Lardo buys another zeddy

Post by Lardo Boffin »

A fairly nice working issue one with a bonus keyboard. But no feet.

85450017-6AD0-4C44-B28F-C030CEA38CFF.jpeg

Strangely deformed top left corner. There is no sign of impact damage inside to suggest something heavy was dropped onto it. Maybe thats how it came out of the mold?

8D35243D-A469-49E9-84FF-07261AC17405.jpeg

Nicely socketed.

8FA95781-A614-4AAF-85B5-F77D53919572.jpeg
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Moggy
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Re: Lardo buys another zeddy

Post by Moggy »

Looks like a put together job. Issue 1 board with later ULA, ROM and Zilog CPU.

The "NO K" on the heat sink looks ominous.
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Paul
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Re: Lardo buys another zeddy

Post by Paul »

Looks like heat damage. Maybe the previous owner was a hot girl?
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Lardo Boffin
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Re: Lardo buys another zeddy

Post by Lardo Boffin »

Moggy wrote: Thu Sep 29, 2022 3:34 pm Looks like a put together job. Issue 1 board with later ULA, ROM and Zilog CPU.

The "NO K" on the heat sink looks ominous.
I thought that about NO K but it boots fine. The picture is far from great but that won’t matter soon.

One of the internal screws was in the wrong place so clearly been messed around with.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
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Lardo Boffin
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Re: Lardo buys another zeddy

Post by Lardo Boffin »

Paul wrote: Thu Sep 29, 2022 3:54 pm Looks like heat damage. Maybe the previous owner was a hot girl?
An interesting thought!

I was wondering about heat damage but couldn’t think of any way it could sink like that without having more of an effect? But I guess I will never know. The guy who sold it found it in a loft clearance I think.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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mrtinb
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Re: Lardo buys another zeddy

Post by mrtinb »

My first thought was that "N O K" was an abreviation of "Not OK". However it makes more sense that the abreviation is "NO K". :)
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1024MAK
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Re: Lardo buys another zeddy

Post by 1024MAK »

Maybe the ULA and/or the Z80A were renewed to fix the fault. We don’t really know how old the NO K writing is, and the ULA and Z80A have newer date codes compared to the other parts.

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Lardo Boffin
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Re: Lardo buys another zeddy

Post by Lardo Boffin »

A nice working issue three with stick on FileSixty keyboard (https://sinclairzxworld.com/viewtopic.p ... 961#p48961):

EC49891F-917F-4D57-AA3A-19C74CD911DC.jpeg
A424AD2B-C44C-4E6D-9855-72E3FFC40F1C.jpeg
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
David G
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Re: Lardo buys another zeddy

Post by David G »

Lardo Boffin wrote: Mon Oct 24, 2022 3:16 pm A nice working issue three ...
Is that RAM chip a 4801 type 1KB static memory? I'm used to seeing the two smaller RAM chips, not the single larger chip
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1024MAK
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Re: Lardo buys another zeddy

Post by 1024MAK »

Actually that one looks like a NEC µPD4016 which is a 2k x 8 SRAM.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
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