Andy Rea's original ULA design blog/schematic.

Discussions about Sinclair ZX80 and ZX81 Hardware
Moggy
Posts: 3231
Joined: Wed Jun 18, 2008 2:00 pm

Andy Rea's original ULA design blog/schematic.

Post by Moggy »

Re-discovered this whilst browsing other things and thought it worthy of repost on the the site for historical reasons if nothing else and also for the techies who may learn something from the text.

http://www.rtin.be/zx81/ZX81.ULA.Replac ... 12.43).htm

Also this..

http://www.rtin.be/zx81/ZX81.ULA.Replac ... 41.45).htm
Last edited by Moggy on Sat Aug 27, 2022 7:33 pm, edited 1 time in total.
Lardo Boffin
Posts: 2161
Joined: Sat Nov 26, 2016 2:42 am

Re: Andy Rea's original ULA design blog/schematic.

Post by Lardo Boffin »

Thanks Moggy.

I only get raw html on the first link but the second one works fine and shows schematics.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
avrovulcan
Posts: 45
Joined: Sun Nov 03, 2019 9:56 am

Re: Andy Rea's original ULA design blog/schematic.

Post by avrovulcan »

Cheers for posting the link. This will come in very useful.
Moggy
Posts: 3231
Joined: Wed Jun 18, 2008 2:00 pm

Re: Andy Rea's original ULA design blog/schematic.

Post by Moggy »

That's weird Lardo!

Works for me with Firefox win 7 but not google chrome win10!

However the html in this zip should work.

This is already on the forum courtesy of Mrtinb.

Also archived here...

http://web.archive.org/web/200904262218 ... A/ula.html
Attachments
ZX81 ULA Replacement ula.zip
(370.93 KiB) Downloaded 131 times
User avatar
mrtinb
Posts: 1906
Joined: Fri Nov 06, 2015 5:44 pm
Location: Denmark
Contact:

Re: Andy Rea's original ULA design blog/schematic.

Post by mrtinb »

I just thought these documents were valuable, so I downloaded them from Internet Archive Wayback Machine (web.archive.org), as the original homepage was gone.

You can see the pages in Firefox. The files are a webarchive, where pictures are included into the HTML.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
dognaldo
Posts: 5
Joined: Tue Oct 18, 2022 5:25 am

Re: Andy Rea's original ULA design blog/schematic.

Post by dognaldo »

Hi, do you know if Andy still has the ULA to sell?
I cannot find this information.
mrtinb I saw on one of your posts that you bought a Andy´s ULA.
Could you please take a good quality photo of the Top and the back of the ULA and post the photos here?
Thanks
Last edited by dognaldo on Thu Oct 20, 2022 8:59 pm, edited 1 time in total.
User avatar
Paul
Posts: 1511
Joined: Thu May 27, 2010 8:15 am
Location: Germanys west end

Re: Andy Rea's original ULA design blog/schematic.

Post by Paul »

Andy has left the zeddy community
In theory, there is no difference between theory and practice. But, in practice, there is.
User avatar
mrtinb
Posts: 1906
Joined: Fri Nov 06, 2015 5:44 pm
Location: Denmark
Contact:

Re: Andy Rea's original ULA design blog/schematic.

Post by mrtinb »

Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
dognaldo
Posts: 5
Joined: Tue Oct 18, 2022 5:25 am

Re: Andy Rea's original ULA design blog/schematic.

Post by dognaldo »

Paul, Martin,
Thanks for the answers.
I'm going to buy a Vla81 from Vretro.
But regardless of buying one I decided to set up a ULA just like Andy's reading the forum topics.
That's why I asked for the photos.
User avatar
mrtinb
Posts: 1906
Joined: Fri Nov 06, 2015 5:44 pm
Location: Denmark
Contact:

Re: Andy Rea's original ULA design blog/schematic.

Post by mrtinb »

There are some pictures of it in this topic:

https://sinclairzxworld.com/viewtopic.php?f=8&t=2928

The design ZIP file in this topic is for an older design.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
Post Reply