Search found 2253 matches
- Wed Dec 09, 2020 10:05 pm
- Forum: Hardware
- Topic: Fixing inherited Sinclair ZX81
- Replies: 34
- Views: 3395
Re: Fixing inherited Sinclair ZX81
"Yeah dad I thought you said we were getting a PS5?" :lol: A ZX81 is better than any PS5. Black and white is the new color. Big pixels are better for the eyes. Membrane keyboard is a good training for the fingers. And with missing sound you better concentrate on the game. 8-) So what could be bette...
- Wed Dec 02, 2020 8:54 pm
- Forum: Hardware
- Topic: Attic 81's - My collection and attempts to repair
- Replies: 51
- Views: 3644
- Wed Dec 02, 2020 8:49 pm
- Forum: ZX BASIC
- Topic: Figure plotting trouble
- Replies: 16
- Views: 1483
Re: Figure plotting trouble
Maybe here are 2 ressources for you with 1k games for your interest:
https://sinclairzxworld.com/viewtopic.php?f=6&t=2349
http://www.rwapsoftware.co.uk/zx81/zx81_software.html
https://sinclairzxworld.com/viewtopic.php?f=6&t=2349
http://www.rwapsoftware.co.uk/zx81/zx81_software.html
- Sat Nov 28, 2020 11:35 am
- Forum: ZX BASIC
- Topic: Figure plotting trouble
- Replies: 16
- Views: 1483
Re: Figure plotting trouble
Error 4 means out of memory.
How much memory is installed, Matt ?
Matt, I think it is a 1k problem.
What gives PRINT PEEK 16389 ?
Should be 128 (16k) not 68 (1k).
- Fri Nov 27, 2020 11:27 pm
- Forum: Development
- Topic: ZX21: CERAMIC RESONATOR
- Replies: 11
- Views: 1020
Re: ZX21: CERAMIC RESONATOR
I think Farnell has it cheap from Murata
https://uk.farnell.com/murata/cstls6m50 ... dp/2913670
Alternatively a 6.500 MHz crystal is not rare as well. Would be more accurate ...
https://uk.farnell.com/murata/cstls6m50 ... dp/2913670
Alternatively a 6.500 MHz crystal is not rare as well. Would be more accurate ...
- Thu Nov 26, 2020 9:13 pm
- Forum: ZX Spectrum Lounge
- Topic: Harlequin video modifications
- Replies: 26
- Views: 22003
Re: Harlequin video modifications
This resistor and capacitor add by Ingo from Germany, he said it help to make picture be in the middle of screen. Okay thanks. ;) But for me it is more Voodoo. The chip supports either composite video and s-video, so s-video output is wasted. Okay is no official connector for the signal aboard but ...
- Thu Nov 26, 2020 8:58 pm
- Forum: Hardware
- Topic: I started on my new ZX-81 replacement board (kit) ZX81+38
- Replies: 37
- Views: 25492
Re: I started on my new ZX-81 replacement board (kit) ZX81+38
Yes, I guess this is all a matter of preference. 

- Thu Nov 26, 2020 8:53 pm
- Forum: Development
- Topic: ZX21 Project ZX81 Replacement PCB
- Replies: 61
- Views: 5014
Re: ZX21 Project ZX81 Replacement PCB
The AS 6C1008-55PCN is CMOS only so not great for a TTL Computer. You can use the 512K Byte big brother however and I do have some of those. Is there much software that needs more than 32K? You would, of course, need to add additional logic to get more than 16K working. A6SC1008 works great with TT...
- Sat Nov 21, 2020 12:07 am
- Forum: Hardware
- Topic: I started on my new ZX-81 replacement board (kit) ZX81+38
- Replies: 37
- Views: 25492
Re: I started on my new ZX-81 replacement board (kit) ZX81+38
A NAND gate with inverted inputs and inverted output is logically the same as an OR gate.
Personally I prefer using an OR symbol rather than an AND symbol with all inverted.
Personally I prefer using an OR symbol rather than an AND symbol with all inverted.
- Tue Nov 17, 2020 8:32 pm
- Forum: Hardware
- Topic: Trying to make a 32K mod on Zx81 together with other mods
- Replies: 4
- Views: 623
Re: Trying to make a 32K mod on Zx81 together with other mods
Did this board run before the modification with the other components or just a first try ? Maybe you just need another setting of trimmer R2 on the ZX8-CCB module as there is no Ferranti ULA inside but a rework (with possibly other voltage levels at the output). Just make a photo of the trimmers pos...