ADDING A C64 POWER CONNECTOR TO A C128 POWER SUPPLY latest updates and/or corrections 4-7-2013 A C128 power supply puts out the same two voltages as a C64 supply. However, the 128 supply is more reliable and doesn't suffer the same bad reputation as the C64 "brick". It can handle higher current on the 5V line and will allow the 64 to run heavier loads such as a RAM Expansion Cart which normally comes with its own beefier power supply. Of course the C128 PS has a different type of connector which doesn't fit a C64. However, with the addition of a "pigtail" cable and connector, that supply can work with a C64. NOTE: It's important that you make the proper connections to the wires of your C128 supply. I've seen two alternate versions of that power supply, one with the same wire colors and one with them reversed! One way to identify the 9VAC source is that an ohm meter will read low resistance when measuring across the transformer winding. A way to tell the 5V source is that its wires will be heavier since that source can supply more current. The most common C128 supply is made by Mitsumi, UL (Underwriters Laboratories) number 47K4 stamped on the case bottom and a Commodore part number of 310416-01. An alternate PS was made by Tokin, has a CBM part number of 316416-07 but uses the standard wire colors and UL 79K7. The one non-standard alternate PS I saw has -reversed- wire colors and was made in Taiwan, CBM part number 310416-01 and UL 94H8. I don't know who made it but it has "DSP-128" stamped on the case. You can either cut the cable off a defective C64 PS or buy a four wire cable and DIN connector to do this modification. Wires must be insulated from each other to prevent shorts between wires. It's best to "stagger" or offset each of the four wires so, if the insulation breaks down, they still can't touch each other. View the photos to see how it's done. The color coding of the wires inside each cable will be different, so the correct ones need to be identified and connected together. Note that incorrect connections can damage the supply and/or the computer! Below is the most common colors used an both 64 and 128 supply wires, but be aware that each vendor of a power supply can use their own wiring color code!!!. Note: as an alternative to "pigtailing", you can cut or drill a hole in the PS case and connect a long C64 cord directly to the inside of the C128 PS. You will want to add some kind of strain relief so tugging on the added cable doesn't cause eventual wire breakage and/or short circuits. Don't cut the C128 cable off the supply even if it's not to be used. It has a sense line inside that monitors the supply output. Whichever cable is not used, it's a good idea to cap the end so it doesn't accidentally touch metal and cause a short. STANDARD ALTERNATE SOURCE C64 POWER CABLE C128 POWER CABLE C128 POWER CABLE + 5VDC BROWN RED BROWN - GROUND BLUE BLACK WHITE 9VAC BLACK BROWN BLACK 9VAC BLACK WHITE RED sense NC YELLOW YELLOW GROUND NC GROUND BRAID GROUND BRAID Ray Carlsen Carlsen Electronics If you spot a mistake here, please let me know. Questions and comments are always welcome. Thanks!