How to connect a C-64 to a modern TV’s S-Video input

In the 1980s, a computer monitor offered a clearer picture than a TV by eliminating the need to modulate/demodulate the video signal, which caused degradation. But in 2003, it’s next to impossible to find affordable composite monitors for 20-year-old computers, and when you can find them, their size pales in comparison to a $99 TV. Why bother with a really old, curvy 13″ monitor when you can retro-compute in luxury on a flat 19″ TV?
Fortunately, if a TV offers composite jacks, you can connect a computer directly to it. No tricks involved–you connect it just like you would a VCR.

But Commodore 8-bit computers (the 64, 128, and Plus/4) used a trick to get a clearer picture: They seperated the chroma and luma signals. This is exactly what S-Video does today. So it’s possible to get a better-still picture out of a Commodore, if your TV has S-Video jacks.

Older C-64s had a 5-pin video connector that only provided straight composite.

Making video cables isn’t difficult, assuming you have decent soldering skills. Usual disclaimers apply: I make no guarantee as to the accuracy of this information. I believe my sources are accurate but I don’t have a working Commodore to try this on right now. Connecting the cables wrong should only result in lots of noise and lots of snow on your TV screen, but if you somehow mess up your computer, it’s not my responsibility.

Later C-64s, C-128s and Plus/4s used an 8-pin DIN connector. S-Video uses a 4-pin mini-DIN connector, the same connector used on Macintosh keyboards from about 1986-1997.

If you already have a Commodore video cable, you can easily make an adapter. Get a 4-pin mini-DIN connector and two female RCA plugs, red and yellow. Connect S-Video pin 3 to the center of the yellow plug. Connect pin 2 to the outside of the yellow plug. Connect pin 4 to the center of the red plug, and pin 1 to the outside of the red plug.

If you don’t have a cable but can locate the appropriate connectors, you can make a cable like so:


Commodore S-Video

2 4 3
4 5 2 1
1 8 3
6 7

(solder side) (solder side)

Commodore pin 1 goes to S-Video pin 3 (luma)
Commodore pin 6 goes to S-Video pin 4 (chroma)
Commodore pin 2 goes to S-Video pins 1 and 2 (ground)

Commodore pin 3 goes to the center of an RCA connector for audio. Connect the outside of the RCA connector to Commodore pin 2.

To make a straight composite cable for a C-64 or VIC-20 (the VIC had a 5-pin plug, and so did early 64s–the later plug is backwards compatible with this 5-pin plug), connect Commodore pin 4 to the center of a yellow male RCA plug. Connect Commodore pin 2 to the outside of the yellow plug. Connect Commodore pin 3 to the center of a white RCA male plug, and Commodore pin 2 to the outside of the white plug.

(Why am I posting about 20-year-old 8-bit computers? Somebody asked, that’s why. Besides, 8-bits were/still are a lot more fun than a PC/XT.)

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