ZX80 video improvements

Discussions about Sinclair ZX80 and ZX81 Hardware
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Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

ZX80 video improvements

Post by Lardo Boffin »

Hello all

I am finally the proud owner of a ZX80. :D It works but the output on my telly (even an old CRT) is predictably poor.

Are there any non-invasive methods of improving the output? Its is such nice condition I don’t want to open the case.

By way of example there is the Chroma 81 for the ZX81 - is there anything similar for the ‘80?
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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1024MAK
Posts: 5103
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX80 video improvements

Post by 1024MAK »

ZX8-CCB can be used ;)
I upgraded the ZX80 that Richard owned. I put the ZX8-CCB in the modulator can as that was what was requested. But you don’t have to do that.

Chroma 80 interface (coming soon) according to Paul’s web site...

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
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Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
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Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ZX80 video improvements

Post by Lardo Boffin »

Thanks Mark. I will wait for the Chroma 80. I really don’t want to make any changes to this one.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
albertusj
Posts: 77
Joined: Sat Aug 18, 2012 12:44 am
Location: Somerset-West, South-Africa
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Re: ZX80 video improvements

Post by albertusj »

I had great success with the 555 based back porch generator from:

http://zx.zigg.net/misc-projects/

It works very well. Granted it is a bit more complicated, but if you add an external power source you won't have to open your ZX80 up at all. Here it is working on my ZX80:

http://www.myprius.co.za/ZX80kit/100_6219.JPG
ZX80/ZX81/ZX Spectrum
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ZX80 video improvements

Post by Lardo Boffin »

Thanks for that. So it takes the normal signal directly from the ZX80 and improves it without any case opening? Impressive!
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
User avatar
1024MAK
Posts: 5103
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX80 video improvements

Post by 1024MAK »

I think that circuit only works on the composite video signal, not the RF (UHF) TV aerial signal.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
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