Hello All & Dead ZX .. probably

Discussions about Sinclair ZX80 and ZX81 Hardware
thedevworks
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Joined: Mon Mar 04, 2019 5:33 pm

Re: Hello All & Dead ZX .. probably

Post by thedevworks » Tue Mar 05, 2019 4:03 pm

fair point that was worth trying, I tried on another TV and it was a little different.

Either.. A few times I got a very steady black screen (No cursor etc, just black)

the other times I got crazy noises and patterns like in the video

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Hello All & Dead ZX .. probably

Post by 1024MAK » Tue Mar 05, 2019 4:36 pm

Modern TVs, if they can’t detect the back porch part of the video signal, they get their auto calibration of the black video level wrong. This results in a very dark image even with the brightness and contrast turned up to full or nearly full.

Mark

thedevworks
Posts: 8
Joined: Mon Mar 04, 2019 5:33 pm

Re: Hello All & Dead ZX .. probably

Post by thedevworks » Wed Mar 13, 2019 6:10 pm

Oh well, I tried first the CCB because it was the least disruptive, which didnt work, followed by a new ULA, which also results in the same video signal. I guess now the only thing left to do is replace the other chips!

thedevworks
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Joined: Mon Mar 04, 2019 5:33 pm

Re: Hello All & Dead ZX .. probably

Post by thedevworks » Thu Mar 14, 2019 12:31 am

Ok I was wrong, the new ULA does work!! Keyboard is a bit iffy, but for now, I'm happy! :D

thedevworks
Posts: 8
Joined: Mon Mar 04, 2019 5:33 pm

Re: Hello All & Dead ZX .. probably

Post by thedevworks » Thu Mar 14, 2019 12:33 am

Image

:P :P :P :D :D :D

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Hello All & Dead ZX .. probably

Post by 1024MAK » Thu Mar 14, 2019 1:12 pm

Good to hear that you are up and running (well, once you have sorted the keyboard) :D

Mark

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Andy Rea
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Re: Hello All & Dead ZX .. probably

Post by Andy Rea » Thu Mar 14, 2019 5:58 pm

McKlaud wrote:
Tue Mar 05, 2019 1:16 pm
Dishwasher would be better ;)
i had a commodore pet universal main board ( from a cbm 4032 machine) in the kitchen sink... my missus thought i'd gone nuts... works a treat and is clean to boot now :D :D
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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