Sinclair ZX80 / ZX81 / Z88 Forums

Well, with some new ULA's replacement no any super composite board is needed. The ULA could drive a TV directly with the proper black level.

See this below

As some of you may know i am developing a new ULA replacement. so should it be able to drive the UHF modlator? Or is composite video only ok. Regards Andy Hi Andy In my ULA development I dropped compatibility with the modulator. However if you think about the 100% drop-in replacement for the origin...

I preferred a square mosaic created by the previous version. Issue 2 works fine but the mosaic is bit overstretched horizontally for my taste.

Anyway, good job!

Nice!

Zschopower: Thank you for sharing this information.

Participants from Denmark, The Netherlands, Switzerland and Germany only. Well, it seems that the ZX81 is there still strong. Keep going.

Yeah! Master of Disaster

Congratulation Andy!!!

My ULA was also tortured and I did a few minor mods earlier today. Now Zeddy boots up every time to the 'K' prompt. Screen and border inversion works as it should. Anyway, still works in progress.

Superfo: welcome to the club

Andy:

The small smd inductor (e.g. 1uH) and than a 0.1uF capacitor between supply rail and GND might be a good idea. I will give it a try.

It is look like that I should assemble the board again, because in this one I've got some synch issues. When I press the board in the socket hard I am getting the "K" prompt on the screen. There is some noise on the video out too. I've been thinking about different type of a NPN transistor there. At...

Mark,

Andy is miles ahead of me. His ULA is working perfectly fine My version is nearly there.