Sinclair ZX80 / ZX81 / Z88 Forums

If I remember this right,
for a RAND USR 836 you need to be in Fast mode

Hi,
last post was quite some time ago, any news?
Is it possible to have different display sizes for differnt time for own loops?

Cheers
Paul

@Charlie, I like your tinyurl best :D @all well my wife is looking a horrorfilm, that gives me some time for my legacy zx80. I replaced all IC's against 74HC, and voila, my keyboard has also gone mad :? (even worse than what I have read here): only a few rows are fully functional, the right side mos...

FANTASTIC!!!

My Pension Day will be somewhere around ZX80's fiftyth Birthday
so I do hope to get one a few days before that
I was lucky to get a test board from Lee,
Charlie, please take me as a testuser, too
Paul

Thanks a lot charlie,

can't wait for the moment when I hold one in my hands!

Please post photos of the empty and soldered board too!

Cheers Paul

hi all, there is a way to get a ZX80 ROM running without problem without the need of cutting the NMI line. It is taken from the german ZX-Team forum, where it was posted recently by the original user holmatic: http://forum.tlienhard.com/phpBB3/viewtopic.php?f=2&t=412 The first instruction in a ZX81 ...

After his last visit, Jens found out that every line is shifted by one "Subrow" upwards with Jumper 5-6 set. You can see this quite good using the shift-S Character as all lines are used there It is the same with my board, with ZX80 and ZX81 rom. Is this the same on the other boards? @Lee, has this ...

Yes, correct no connection to the pad of R30. Thanks for the description, this explains why nothing happened to the signal level: R32 is exactly in the middle position, I forgot to try to change its setting :oops:, or even to compare their settings, because there is absolutely no problem with my mon...

Hi Lee, I also misinterpreted the photo. Luckily I could see #4 in live. The yellow wire connects the additional diode directly from R37 to D13, no connection to R31. I hope that makes it clear. Why my modification from 1K to 500 Ohm did not increase the video level I cannot tell. I checked the valu...

Neither good nor bad. At the moment 4 out of 5 Boards are completely built. One does not work (Jens), it gives no signal to the screen, there will be further investigation this weekend. Two work with the known error of the keyboard. SirMorris replaced the diodes with no effect. My board still works ...