ZX80 video improvements

Discussions about Sinclair ZX80 and ZX81 Hardware
Post Reply
Lardo Boffin
Posts: 950
Joined: Sat Nov 26, 2016 2:42 am

ZX80 video improvements

Post by Lardo Boffin » Thu May 16, 2019 5:24 pm

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)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

User avatar
1024MAK
Posts: 2370
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX80 video improvements

Post by 1024MAK » Thu May 16, 2019 5:35 pm

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

Lardo Boffin
Posts: 950
Joined: Sat Nov 26, 2016 2:42 am

Re: ZX80 video improvements

Post by Lardo Boffin » Thu May 16, 2019 6:04 pm

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)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

albertusj
Posts: 44
Joined: Sat Aug 18, 2012 12:44 am
Location: Somerset-West, South-Africa
Contact:

Re: ZX80 video improvements

Post by albertusj » Mon Jun 24, 2019 11:14 am

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: 950
Joined: Sat Nov 26, 2016 2:42 am

Re: ZX80 video improvements

Post by Lardo Boffin » Mon Jun 24, 2019 8:51 pm

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)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

User avatar
1024MAK
Posts: 2370
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX80 video improvements

Post by 1024MAK » Mon Jun 24, 2019 11:10 pm

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

Mark

Post Reply