Earliest known ZX81?

[Erm]

Mentioned in another recent topic, but I thought I'd share it here so that people can find and add details of early ZX81's.

This one is very early, so I have bragging rights for now .

(date codes are year followed by week number, for those that aren't aware)

Modulator: 8106
ULA chip: 8102 (type 158)
Z80: 8030 (which is older by 9 weeks than the one in my ZX80 and has all the same markings/other numbers!)
RAM: single chip configuration, 8028
ROM: no date and I haven't yet checked if it's the bugged early one.

Notable observations: it came with a ZX80 PSU and leads (I appreciate that doesn't necessarily mean that it was sold like that as I don't have it from new). The rubber feet are thinner and softer than the 'normal' ones. Most resistors are very 'sun tanned' and the ceramic caps are fairly large.

Condition: Very good, has never had anything on the expansion port. Everything seems original. Keyboard connectors are broken.

[Lardo Boffin]

Very nice! Was it a kit build? I have had a few early ones (but not that early!) with ZX80 PSUs and cables that looked like they might be. My assumption was that if they bought a kit version they didn't get a PSU etc. and therefore used one that was easily available at the time.

[Erm]

Known kit ones that I've had, so far, always have empty solder holes for the unused ram chip/s configuration, which this one doesn't, and also 3 holes in the lower left corner (for the channel switch) and this one doesn't have holes there either so I would say it was a factory made one.

[1024MAK]

Mentioned in another recent topic, but I thought I'd share it here so that people can find and add details of early ZX81's.

This one is very early, so I have bragging rights for now .

Sorry, when I started reading this post, I thought it was Lardo with yet another Zeddy

Mark

[Erm]

Sorry, when I started reading this post, I thought it was Lardo with yet another Zeddy

Mark

No, it's me. I do pretty much the same, but from Germany!

This one came from the UK though, incidentally.

[Erm]

Did some delving, found this post.

https://www.sinclairzxworld.com/viewtopic.php?t=1871

Same ULA date (8102) and Modulator date (8106).

So, joint earliest perhaps!

It looks like this old pic linked to from that topic may also be an 8102 ULA:
https://www.sinclairzxworld.com/downloa ... hp?id=2860