Sinclair ZX80 / ZX81 / Z88 Forums

It looks like 2 pcs of 1K 4SRAMs and i i'm not sure what you mean by hand drawn, but i do know that these tin tracks are very vulnerable (compared to an etched copper board) even with a good soldering-station removing a non socketted chip is a trip and chances are some small mistake will cause diffi...

Cheers for the advice Moggy & RWAP! Ok so put a wee plastic key-way/spacer in the gap, so that should be good now. Still no go with the keys. I realised the Newline/Function key also is not working. So that makes 5 keys (H-J-K-L-NL). Seeing there are 10 keys in a row, could this be a keyboard matri...

Ok, Thanx, i found a 62256 available, and then started wondering whether it would be possible (maybe even easier for testing purposes) to connect it on the edge connector first (before i start ripping out a ram-chip that actually works) Am right to actually want to connect A14 & A15 on the board in ...

Oh that sounds like a much better solution with the 32K-8bit, could you be more specific ? i can see that this new-old hobby is going to get right out of hand .. :lol: Would this one work ? http://www.rotor.eu/pdfframe.php?pdf=http://www.rotor.eu/pdf/geheugen/27C256.pdf this i could just buy easily ...

Optrek-RS stands for Pull-up Resistance(s) The book was originally written by Stephen Adams (1982), but this board comes out of the dutch version Published by Kluwer (mine has ISBN 90201 1640 1 that was the 3rd print 1984)

I do actually have one of these, but i was a bit to young to get it functioning properly, now i've dug it up and in the booklet, it describes that any address above 61440 will communicate with the port in fact it just test if A12, A13, A14, A15 are on but this obviously this can be separated out mor...

Maybe a bit odd to add to an old topic like this,but i just dug up the Old zx81, that my stepdad bought and i consumed all the time on, It works (i had to reconnect the keyboard) but my ZX 16K RAM doesn't work anymore probably because i plugged it in with the interface-board which had a short. More ...