As I was waiting for the Phoebe PCBs I had the opportunity to work on a Commodore 64C board. I know next to nothing about those but I got the board cheap in rather sorry state and figured I’ll try to fix it – for the fun of it.
Long story short, the board does work now but it was missing the TV modulator so there was no video output at all, as on these later models the video amp is also a part of the modulator. So I had to come up with a replacement. Now, schematics for C64 are available and I wasn’t the first person with that idea but for some reason all the projects I saw on the net were using crude veroboard/wire based hacks, with very questionable component selection.
So here’s my take on this:
There’s no actual modulator in there anymore, just the luma+chroma amps based on low-noise high gain transistors. Both S-Video and composite signals are being generated. I’ve built two of these and now I’m looking for a C64C owner willing to test the other one. Note, this is only compatible with the C64 models equipped with the new VIC chip running from 5V!
What I offer is this here PCB, free with worldwide shipping. What I expect in return is a report from someone who has experience with C64 and it’s video quality – especially on LCD monitors – who can tell me if it’s acceptable or not. I think all these 300ohm resistor hacks in S-Video cables are unnecessary, but I need someone with better idea on what should be on the screen than I have.
Obviously installation will require soldering so if you have to ask, it’s not for you.