Search found 2764 matches

by 1024MAK
Sat Apr 04, 2020 7:30 pm
Forum: Hardware
Topic: ZX Spectrums problems : diagnostic software ?
Replies: 81
Views: 19526

Re: ZX Spectrums problems : diagnostic software ?

I will help where I can. First though, just play with it and get used to the controls and the effect they have. What type of probe(s) were supplied? Do they have a switch marked 1:10 or similar? With non-complex repetitive waveforms, adjust the signal level, timebase and trigger controls until you g...
by 1024MAK
Tue Mar 31, 2020 11:05 pm
Forum: Hardware
Topic: ZX81 grey vertical lines on screen
Replies: 6
Views: 210

Re: ZX81 grey vertical lines on screen

SN74LS02N is a standard logic gate (Quad 2-input positive-NOR gates) and is my best guess... The ‘5CALY7K’ is a manufacturer batch or production number/code. I’m also guessing that there may be wiring between it and the ULA. What sort of power supply unit (PSU) are you using to power your ZX81? Mark
by 1024MAK
Tue Mar 31, 2020 4:37 pm
Forum: Development
Topic: Midiplayer, using a DUART and a LCD
Replies: 21
Views: 1008

Re: Midiplayer, using a DUART and a LCD

Moggy wrote:
Tue Mar 31, 2020 3:43 pm
I don't know why but in the UK the song was called 99 RED(ROT) balloons not Luft balloons.
link to YouTube English version
Wikipedia page

Mark
by 1024MAK
Mon Mar 30, 2020 11:24 am
Forum: Emulators
Topic: ZXSimulator for the Sinclair QL
Replies: 6
Views: 255

Re: ZXSimulator for the Sinclair QL

Hello and welcome. You may wish to properly introduce yourself in the welcome area ;-)

Mark
by 1024MAK
Mon Mar 30, 2020 11:05 am
Forum: Hardware
Topic: ZX81 grey vertical lines on screen
Replies: 6
Views: 210

Re: ZX81 grey vertical lines on screen

Hello and welcome. You may wish to properly introduce yourself in the welcome area ;-) Can you please post up a photo of the display image that you are getting on your TV so that we can see the problem that you are talking about. There are three different versions of the Sinclair ULA. Any ULA versio...
by 1024MAK
Sat Mar 28, 2020 4:59 pm
Forum: Hardware
Topic: Newbie Timex Sinclair 1000 Questions
Replies: 1
Views: 147

Re: Newbie Timex Sinclair 1000 Questions

Hello and welcome. You may wish to properly introduce yourself in the welcome area ;-) I’ve moved your thread to the hardware area, as most of your questions are hardware related (you posted in the trading/sales section). To answer some of your questions: PSU Without a memory/RAM pack connected, any...
by 1024MAK
Thu Mar 26, 2020 7:33 pm
Forum: Hardware
Topic: ZX81 repair help needed - strange fault!
Replies: 5
Views: 371

Re: ZX81 repair help needed - strange fault!

Fully working now?

If yes, well done :D

Oh, and welcome to the forum :D

Mark
by 1024MAK
Thu Mar 26, 2020 7:11 pm
Forum: Hardware
Topic: ZX Spectrums problems : diagnostic software ?
Replies: 81
Views: 19526

Re: ZX Spectrums problems : diagnostic software ?

Thanks a lot Mark, I'll buy the one you recommanded. Happy to help, but I think it was Paul that pointed to the ‘scope you are thinking of buying, not me. Yes, I live in England, in fact in the South-West of the country. I work for an infrastructure company and am classed as a critical / key worker...
by 1024MAK
Thu Mar 26, 2020 3:08 pm
Forum: Hardware
Topic: ZX Spectrums problems : diagnostic software ?
Replies: 81
Views: 19526

Re: ZX Spectrums problems : diagnostic software ?

For most 8 bit computers normally an analogue bandwidth of 20 MHz to 25 MHz is the minimum recommended. For the remaining 8 bit and most 16/32 computers (including Atari ST/STFM/STE machines), an analogue bandwidth of 40 MHz is the minimum recommended. That is an unusually low price for the specs th...