I started on my new ZX-81 replacement board (kit) ZX81+38

Discussions about Sinclair ZX80 and ZX81 Hardware
User avatar
mahjongg
Posts: 171
Joined: Tue Nov 24, 2015 10:25 pm

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by mahjongg »

Finalized the PCB
Image

also uploaded production files to github:
https://github.com/mahjongg2/ZX81plus38 ... LICENSE.md

more pictures here:
https://revspace.nl/ZX81plus38_simple_t ... s_finished
User avatar
1024MAK
Posts: 3121
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by 1024MAK »

👍 8-)

Mark
McKlaud
Posts: 283
Joined: Tue Dec 19, 2017 10:02 pm
Location: St Albans, UK

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by McKlaud »

Looks great and thank for sharing.
Claudius
----------
GTS1000TX
Posts: 12
Joined: Sat Apr 13, 2019 3:44 pm

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by GTS1000TX »

This looks very cool. Some Atari folks designed new boards for Its 8bit line. I wanted to build one, but could not justify the expense. Was going to be over $500 to build one myself. The wife would kill me. But this appears more affordable. And I just happen to have a Timex Sinclair 1000 that may have a bad PLA chip. Looking forward to your bill of materials list.
User avatar
marste
Posts: 145
Joined: Sun Aug 10, 2014 9:58 pm
Location: Italy
Contact:

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by marste »

@mahjongg very very nice project, compliments!

regarding jumpers, would it be nice to have one switching from the 4k ZX80 ROM to the 8k ZX81 one (and also slow mode)?
(with the 16kbyte ROM both fit at the same time and is a matter of switching just address bit 13)
User avatar
mahjongg
Posts: 171
Joined: Tue Nov 24, 2015 10:25 pm

Re: I started on my new ZX-81 replacement board (kit) ZX81+38

Post by mahjongg »

The latest version (the one uploaded to GitHub) has exactly those jumpers, on the bottom side, so you can still change them even after soldering in a ROM socket. And yes, one of the jumping options is to use the old original ROM, the default is to use a modern OTP, in 8 and 16K variations.
Post Reply