15-06-2021, 01:21 PM
I don't remember the details of making it, but there were either experiments for parts of the design on other boards or a fair amount of ripping up and trying again. Some of it is inevitably based on the Cox 153 PAL coder with which I was familiar. The SPG part uses a Philips SAA1043 SPG chip. This needs at least 5.7V supply to guarantee corect operation. Some parts of the design are likely "borrowed" from a Philips broadcast SPG.
When I did the design there were no video opamps,or at least none that were low cost and low hassle. The EL2020 arrived around 1989. Programmable logic did exist but it was very low density and relatively expensive.
I did the original schematics by hand, before I had Orcad. I think I transcribed them on to Orcad at some point but can't find the files. I should still have the original pencil on drafting film sheets. Finding them is another matter.
When I did the design there were no video opamps,or at least none that were low cost and low hassle. The EL2020 arrived around 1989. Programmable logic did exist but it was very low density and relatively expensive.
I did the original schematics by hand, before I had Orcad. I think I transcribed them on to Orcad at some point but can't find the files. I should still have the original pencil on drafting film sheets. Finding them is another matter.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
