Search found 875 matches

by Lardo Boffin
Tue Jan 01, 2019 12:35 pm
Forum: Hardware
Topic: Faulty ZX81 logic probe results
Replies: 6
Views: 765

Re: Faulty ZX81 logic probe results

While trouble shooting my poorly rebuilt zeddy I did benchmark logic probe tests on a healthy Z80 and ULA:- https://www.sinclairzxworld.com/viewtopic.php?f=7&t=2592&start=130#p32197 In my case it was a dodgy transistor. Not sure which one as I replaced them both. Are you able to chip swap with a wor...
by Lardo Boffin
Sun Dec 30, 2018 9:19 pm
Forum: Development
Topic: Smooth horizontal scrolling
Replies: 6
Views: 949

Re: Smooth horizontal scrolling

I must admit I have not tried dropping back to BASIC with the double buffering code. It may be that the code upsets some BASIC system variables.
by Lardo Boffin
Sat Dec 29, 2018 1:58 pm
Forum: Development
Topic: Smooth horizontal scrolling
Replies: 6
Views: 949

Re: Smooth horizontal scrolling

Hi Bruno

I can’t see an attached file?

You could always try very simple double buffering:-

viewtopic.php?f=6&t=2372&p=25375&hilit= ... ing#p26810
by Lardo Boffin
Tue Dec 25, 2018 4:51 pm
Forum: Welcome Area
Topic: Merry Xmas and Happy Holidays
Replies: 9
Views: 1236

Re: Merry Xmas and Happy Holidays

Merry Christmas! :D :D
by Lardo Boffin
Mon Dec 24, 2018 4:12 pm
Forum: Hardware
Topic: Spectrum Fast Loading via iPod etc.
Replies: 1
Views: 590

Spectrum Fast Loading via iPod etc.

Having had a go at this process (e.g. https://www.google.co.uk/amp/s/stiggyblog.wordpress.com/2011/09/04/turbo-loading-zx-spectrum-games-via-iphone/amp/) I managed to get it to work with the original cassette cables that came with my Spectrum but only by very careful placement of the mono jack in a ...
by Lardo Boffin
Fri Dec 21, 2018 1:59 am
Forum: Hardware
Topic: Spectrum +3 floating bus mod
Replies: 0
Views: 628

Spectrum +3 floating bus mod

I have applied the floating bus partial implementation mod from here https://spectrumforeveryone.com/technical/performing-the-in-ff-mod-on-a-spectrum-2a-3/ to a spare +3 I have at the moment and it seems to work fine. As a quick aside does anyone know of any games that rely on this behaviour to work...
by Lardo Boffin
Fri Dec 21, 2018 1:29 am
Forum: Hardware
Topic: Issue 4B Spectrum with dot crawl in black and white
Replies: 13
Views: 458

Re: Issue 4B Spectrum with dot crawl in black and white

Fitted the new caps and it certainly reduced the jail bars. It made little difference to the stability of the black however. I tried another identical ULA from a work in progress Spectrum (a 4S) and it made no difference. I also put back the original Z80 (that I removed to make the DIVMMC work) and ...
by Lardo Boffin
Thu Dec 20, 2018 9:33 pm
Forum: Hardware
Topic: ZX81 with no display
Replies: 5
Views: 321

Re: ZX81 with no display

A kludge fix zeddy is one with the early bugged ROM - it has maths issues. They were sometimes fixed by placing a PCB over the Z80 to skip the unwanted instructions and correct some issues. A photo of one can be found here:- https://www.sinclairzxworld.com/viewtopic.php?f=7&t=2153&start=150#p26265 T...
by Lardo Boffin
Thu Dec 20, 2018 7:53 am
Forum: WANTED
Topic: Z80 processor
Replies: 8
Views: 1359

Re: Z80 processor

I ended up getting a couple from here

https://www.retroleum.co.uk/zx-spectrum-chips

Ideal if you only need one or two - no minimum order value surcharges. :D
by Lardo Boffin
Thu Dec 20, 2018 7:50 am
Forum: Hardware
Topic: ZX81 with no display
Replies: 5
Views: 321

Re: ZX81 with no display

If it turns out you need a Z80 see this thread viewtopic.php?f=9&t=3037