Sinclair ZX80 / ZX81 / Z88 Forums

Having bought a couple of zeddies in the past I recently got two in short succession which had the rarer yellow PCB and type 622 ROMs - the slightly rarer intermediate ROM we are now familiar with.
From seeing two together I wondered if I had seen any more so had a look through some photos…

https://sinclairzxworld.com/viewtopic.p ... 229#p35229
ULA 8128

https://sinclairzxworld.com/viewtopic.p ... 546#p36546
ULA 8132

https://sinclairzxworld.com/viewtopic.p ... 869#p42869
ULA 8130

https://sinclairzxworld.com/viewtopic.p ... 331#p46331
ULA 8128

https://sinclairzxworld.com/viewtopic.p ... 622#p46622
ULA 8141 (may not be - 622 ROM)

https://sinclairzxworld.com/viewtopic.p ... 765#p46765
ULA 8132

https://sinclairzxworld.com/viewtopic.p ... 036#p47036
ULA 8138

Anybody else got / seen a yellow PCB issue one? Does it have a 622 ROM? Just curious!

Or a 622 ROM that is not on a yellow PCB?

"Yellow" PCB? more like beige to my old eyes!


All my ROMs have been replaced by big bang double speed EPROMs but a quick shufty reveals that four of my boards, three beige one green all had 622 ROMS and I only have two 649's, one being a Mostek and the other is the Motorola I got from your good self.

I guess it is more beige than yellow.

Quite a few yellow / beige PCBs with the 622 then. Were they a similar date code to mine?

The two 622s I have to hand are NEC jobbies and not sure how their date code works but they are numbered P18359-192 and P19209-137.
The Mostek is 1982. Can't tell from ULA's as I swapped them all out for Andy Rea's little green marvels and they are in a box somewhere.

Another yellow / beige one with a 622 ROM. Definitely a bit of a pattern going on here.

ULA 8138.

Socketed RAM chip, possibly a kit build.

And 8130 ULA:

https://sinclairzxworld.com/viewtopic.p ... 310#p49310

There must have been a batch of these done!

ULA 8132 and 622 ROM: