Sinclair ZX80 / ZX81 / Z88 Forums

Great news

Funny that I had studied that part of the ZX80 schematic a couple of months ago, I wondered why Sinclair had wired up that multiplexer input like that (pin 5). But I got distracted and never investigated any further...

Mark

If you have a 'scope or logic probe, check Z80 address lines A14 and A15. Mark Or go the whole hog and test every single pin on the Z80 CPU. See the link in my sig for the pin-out. Most pins should be pulsing at various speeds. Not normally used control inputs, or inactive inputs should be logic hi...

A sharp tip lies in wait...

Recent events are:- (Not holidays unless stated) Hallowe'en - 31st October. Although it is not as big here compared to North America. Fairly low key in my town. Very much overshadowed by the Guy Fawkes events. Guy Fawkes Night (also known as Bonfire Night, Firework Night), 5th November. See what Wi...

Yes! I did exactly this for a forum member. I removed the existing PCB from inside the modulator (that's the hardest part). Then fitted a ZX8-CCP. I connected the black wire (0V/ground) to the inside case. Connected the red wire to the +5V supply. And threaded the yellow wire out through to the outs...

mhudson52 wrote: ↑Thu Nov 23, 2017 4:21 pm I bought 500 of them (even though I don't need nearly that many) with the idea of sending most of them to Rich so he can supply folks across the pond much more cheaply than I can with US shipping costs. He and I have just begun a discussion, so stay tuned.

*like*

It looks like it is repeating the bit pattern, so you get half of a character, twice!

Check the pins on the parallel to serial chip (shift register).

Mark

@Barry - I don't have a Mac, but it looks like you are doing good work, so thanks for this

Mark

Great find

So are these available to buy? If yes, where from?

Mark

However, it should have either a green or a red solder resist on the bottom

Mark