Sinclair ZX80 / ZX81 / Z88 Forums

"Yeah dad I thought you said we were getting a PS5?" :lol: A ZX81 is better than any PS5. Black and white is the new color. Big pixels are better for the eyes. Membrane keyboard is a good training for the fingers. And with missing sound you better concentrate on the game. 8-) So what could be bette...

Nice TV

Maybe here are 2 ressources for you with 1k games for your interest:

https://sinclairzxworld.com/viewtopic.php?f=6&t=2349

http://www.rwapsoftware.co.uk/zx81/zx81_software.html

XavSnap wrote: ↑Sat Nov 28, 2020 5:19 am The 4 error point to a variable error, not setup... (LET COS=0)…
In this program SIN & COS are numerics functions.

Error 4 means out of memory.
How much memory is installed, Matt ?

Matt, I think it is a 1k problem.
What gives PRINT PEEK 16389 ?
Should be 128 (16k) not 68 (1k).

I think Farnell has it cheap from Murata
https://uk.farnell.com/murata/cstls6m50 ... dp/2913670

Alternatively a 6.500 MHz crystal is not rare as well. Would be more accurate ...

This resistor and capacitor add by Ingo from Germany, he said it help to make picture be in the middle of screen. Okay thanks. ;) But for me it is more Voodoo. The chip supports either composite video and s-video, so s-video output is wasted. Okay is no official connector for the signal aboard but ...

Yes, I guess this is all a matter of preference.

The AS 6C1008-55PCN is CMOS only so not great for a TTL Computer. You can use the 512K Byte big brother however and I do have some of those. Is there much software that needs more than 32K? You would, of course, need to add additional logic to get more than 16K working. A6SC1008 works great with TT...

A NAND gate with inverted inputs and inverted output is logically the same as an OR gate.
Personally I prefer using an OR symbol rather than an AND symbol with all inverted.

Did this board run before the modification with the other components or just a first try ? Maybe you just need another setting of trimmer R2 on the ZX8-CCB module as there is no Ferranti ULA inside but a rework (with possibly other voltage levels at the output). Just make a photo of the trimmers pos...