The Commodore 64 is an 8-bit home computer originally released in August 1982. The machine is one of the most successful home computers ever produced, with up to 17 million units sold worldwide. The machine is fondly remembered by users for its excellent (for the time) graphical capabilities and its distinctive SID sound chip.
There were two major revisions of the C64. The original C64 and the C64C. Both machines have the same capabilities. Very early C64 machines have a 5 pin DIN connector for video, while later versions have an 8 pin. The two are wired exactly the same, except that the 8 pin connector has a separated chroma (color) output. Earlier C64's didn't output separate Y/C video. RGB is generally not available on the C64.
There was also a C64 games console released. This machine lacked the C64's keyboard and was compatible with cartridge software only. It is of little significance except as a collectors piece. A portable machine called the SX-64 does exist but is extremely rare. The Commodore 128 line of computers is also 100% compatible with the C64, though has slightly worse S-video output quality.
Commodore C64C (PAL) Commodore 128D (PAL)
XRGB-3 Specific settings
If you use a S-Video to RGB transcoder you may need to manually adjust the AFC level to remove screen warping. PAL S-Video signals are not directly compatible with the XRGB3 and will appear black and white.
XRGB-Mini Specific settings
For a PAL C64, set the mini to output 576p. If you do not, the scaling may appear vertically squashed. To zoom in the C64's picture you can use the letterbox modes on the Mini, although you may get a better / more accurately scaled picture by using the zoom mode on your TV instead.
OSSC Specific settings
Since the C64 does not output RGB, a S-Video to RGB transcoder is required. Unfortunately, as of May 2016, the only unit readily available does not work correctly with the C64.
The Extron CD400 transcoder has been confirmed to work.
The Sony YR-1000 or YR-3000 transcoders will work with the C64 and the OSSC under the following conditions:-
1) Set Analogue Sync LPF to 2.5MHz (Max)
2) Adjust the H-PLL coast options so that pre is set to 4 and post is set to 4. You may be able to adjust these values slightly lower if necessary.
3) It may also be necessary to add a 300 ohm resistor on the chroma signal and/or a 75 ohm resistor on the luma signal. Without this, the picture may drop out on very bright scenes.
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