A/V CABLES FOR COMMODORE COMPUTERS 5-23-2014 There are lots of cables out there and none of them are wired the same as an original Commodore. CBM made two types. The earliest was a two-wire used with the VIC20, with one plug each for video and audio. That cable will also work with all versions of the C64. Early C64 boards and the VIC20 have a five pin DIN A/V socket, and later C64's and the C128 series use an 8 pin DIN. I admit I'm not sure who made that particular cable. The next Commodore cable type was a three-wire made for use only with the three rear inputs of a Commodore monitor (1702, 1084, etc.) because it separated the luminance (black and white signal) from the chroma (color information), which is similar to contemporary S-video. That cable has eight pins in the DIN plug to match the A/V socket of later C64's and the 128 and that arrangement produces the best picture on a Commodore monitor. The three colored plugs of that cable match the three colored input jacks on the rear of the monitor. Make sure the monitor switch is in the correct position to use those rear input jacks. Although most Commodore monitors use the three RCA jacks for Y/C video and audio, one has a different connector. The CBM 1902A monitor has a 6 pin DIN and requires the appropriate cable (6 pin DIN to 8 Pin DIN) for use with the computer. If that 6 pin looks familiar, it's the same as used on the computer for its serial cable. Later Commodore computers including the C128 still have a single composite output so any video monitor will work with the appropriate cable. Note: the Commodore three-wire cable will not work with a composite (single wire for video) monitor. The resulting video will be black and white only. Obviously a three wire (8 pin DIN) cable will not work with the VIC20 or the early version C64 as those computers use a five pin DIN A/V jack. FOUR WIRE CABLES AND COMMODORE COMPUTERS OK, now it gets complicated... there are lots of four wire cables out there and none of them were original Commodore AFAIK. They all use a five pin DIN connector and the colors of the wires will -not- match the Commodore receptacles (yellow for video, etc.). There are even different color combinations with different four wire cables! These cables go all the way back to the 1960's. They were originally used in European audio systems. I first saw DIN connectors in Germany when I was in the Army in 1965. If you have a four-wire cable, it will probably still work with your Commodore computer but you must find the plug combinations that matches your monitor. Of course the colors will not match. NOTE: one of those wires of the four wire cable will connect directly to the SID audio -input-. If that plug touches anything metal with the computer on, it can instantly destroy the SID (sound chip). Ask me how I know. FOUR WIRE CABLE CONNECTIONS WITH A COMMODORE (OR OTHER) MONITOR If you have a Commodore monitor but no matching three wire cable, you might have to make do with the more common four wire cable. Switch the CBM monitor to its front inputs. Use those for composite, not the rear S-video jacks. Now, Commodore monitor or not, connect one of the four plugs to the video input of your monitor (yellow socket) and turn the computer on. If the opening screen comes up, that's your composite video line. If the picture has no color, that's video but it's not composite. Turn the computer off each time when you want to change connections. Try each of the other plugs to locate the audio output. If you turn up the volume, you should hear the normal characteristic whine of the SID chip. Once you've found all the correct wires, tape up the unused plugs so they can't short to anything. Note that there is only mono audio out of the computer so connect it to the left audio input if your monitor is stereo. Many TV's or monitors with stereo sound will route the left input to both speakers. ALTERNATE S-VIDEO HOOKUP USING A FOUR WIRE CABLE WITH A CBM MONITOR Although you should not use a four-wire cable with the rear jacks of a Commodore monitor, you can try to see if an alternate hookup will produce an acceptable picture. Switch the monitor to the rear inputs and turn the computer off. As above, test each of the cable plugs, one at a time (computer on only to make the test), to find the correct ones. Two of the four-wire plugs will produce a B/W picture but one of them will look cleaner on the screen. That's the wide band B/W output. Connect that one to the yellow input jack of the monitor and the other video output to the red (color) input jack. You should have a color picture if the connections are correct. The quality of the picture can vary depending on the monitor, specifically if it will accept composite video for its color input. If it looks good, connect the audio and you're done. Be sure to tape up the unused plug (SID audio input) for safety! Ray