Sinclair ZX80 / ZX81 / Z88 Forums

Thank you all, folks.

The scheme I've used is this:




I´ll try the scheme Siggi posted, when I receive the IC. I'll tell you something...

Well, well. I've put my hands on my Zeddy... The first attempt: making composite video mod (1 transistor, 1 resistor and 1 capacitor). I fit it into the Zeddy. It works! But... My ULA is 2C184E... VERY DARK SCREEN! I've read some web pages, and all of them say "2C184E ULA will make a bad picture"......

Hello, nama!

Do you have the "Winky board"?
Is it good for loading tapes into the Zeddy?
Could you please, if you have it, post some photos of that board? If so, I´ll try to make it for my "new" Zeddy...

Thanks in advance.
Jose.

Wow!
Siggi: That's a really nice job!

Thanks, Mike.

I will let you know how this mod is made as soon as I go on with it.

siggi:

I want to update to 32K mem with an 74hc251, but I can´t find M1 signal (pin 12 of 74hc251). Is this MI signal (pin 27 of Z80)?

Thanks in advance.

Congratulations!
Nice job!

Maybe this could help...


----------
| o |
----------
| 7805 |
----------
| | | --> Vout (5Vdc)
| | -----> GND
| ----------> Vin (9 - 12 Vdc)

Good Luck!

Maybe he is adding s&h costs from 1981 until now... You know, travelling through times is very expensive...

Littlejohn: I've seen your mod, and it's a really nice job!. I would like mine was as good as yours. But the question is: Do you really get 32K of continous RAM or do you get 16K at 16K-32K region and 16K at 48K-64K? I think it's the second choice, and I'd wanted 32K at 16K-48K region. Perhaps this ...