Search found 7 matches

by nicad
Sat Oct 05, 2024 2:50 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

It lives! The new keyboard arrived, fitted, and all keys worked first time - the old keyboard goo wasn't that hard to get rid of in my case, guess I was lucky or somebody had replaced it previously? Whilst tinkering, I also fitted a ZX-WESPI (minimal version), replaced the regulator and created a US...
by nicad
Tue Oct 01, 2024 5:41 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

Thanks again both, yes getting there! I connected various pins from one connector to the other and as if by magic, text appears! Knowing the keyboard or cable at least is bad, I thought I might as well cut the scrappy ends off the cable and give it a go. I did once get a couple of numbers, but nothi...
by nicad
Mon Sep 30, 2024 11:41 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

Success! zx81DisplayFixed.jpg And this is what it looks like now! :shock: zx81BottomFixed.jpg So on to the next challenge, the keyboard doesn't do anything. I couldn't immediately find any, but are there any guides on diagnosing keyboard issues? The connector cables look like they have been bent qui...
by nicad
Mon Sep 30, 2024 9:11 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

Fantastic, thanks for both of those, much better than the reference images I found. Now down to work...
by nicad
Mon Sep 30, 2024 6:47 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

After a bit more of an inspection, I found my board has a section of missing links which probably won't help:
zx81missinglinks.png
So I'll work on figuring out where the ends should be and add them back in and check the connectivity of the rest...
by nicad
Sun Sep 29, 2024 11:03 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

Re: ZX81 with mismatched ROM, jumper cable and flat cursor

Thanks for the info! I've carefully removed the ROM fixer board, and plugged the Z80 back in, but the screen looks exactly (pixel by pixel) the same. So based on what you said about broken tracks, I removed the ULA too, however when I pulled the chip out, the metal contact from the socket for pin 31...
by nicad
Sun Sep 29, 2024 3:46 pm
Forum: Hardware
Topic: ZX81 with mismatched ROM, jumper cable and flat cursor
Replies: 16
Views: 4851

ZX81 with mismatched ROM, jumper cable and flat cursor

HI! I've just picked up my first ZX81 from ebay and unfortunately can't get a readable prompt. The board has already been modified with a composite board, but it also seems to have a couple of other mods: It's an issue 1 board with the ROM fix standoff board, but the ROM chip appears to be a later 6...