The Commodore 64 Power Connector Problem

Marc Bilodeau/ Commodore 64

The power connector is the one thing about the Commodore 64 that has always bothered me. It seems like a fundamental design flaw by putting it near the power switch on the right side of the unit. However, when you look at the back of the Commodore 64 with all the ports and peripherals it is understandable why the port is where it is.

The Commodore 64 power connector could easily bend or break

I worry that I would accidentally break or bend the DIN connector by moving the Commodore 64 around and catching it against something. This problem is more worrisome now since my Commodore 64 has a home at its very own space optimized custom desk.

The solution to this problem seems simple enough. Unfortunately, there doesn’t appear to be an adapter on the market for sale. Therefore, I will have to build my own power connector.

The 90 Degree Power Connector

Warning: Unless you have the necessary skills to solder wires and properly use a multimeter, I don’t recommend doing this project yourself. There is a chance you can destroy your precious Commodore 64. Therefore, continue at your own risk.

The Parts

The shielded cable was the most difficult to acquire. Vendors usually require a minimum purchase of at least 25′ or 10 meters. Unfortunately, I only need 6 inches of cable. For my metric friends, that’s ~15cm. Fortunately, I found an eBay Seller that sold a small spool of shielded cable at a reasonable price.

The Tools

The Commodore 64 Power Supply

Important Note: The most concerning issue is the Commodore 64 power supply. Aging power supplies can kill the system. Therefore, test the power before using it with your Commodore 64. Personally, I recommend replacing the power supply altogether.

The Commodore 64 power connector pinout

The Commodore 64 power supply pinout to a power connector

The Commodore PSU (power supply unit) provides 5V DC and 9V AC to the Commodore 64 using a 7 pin DIN Connector (DIN 45329 IEC 10). Although, by looking at the power connector from the power supply, some models have 4 pins while others have all 7. Regardless, the pinout of each power supply remains the same.

The 7 Wire Color Code Cheat Sheet

The 7 wire shielded cable has separately colored wires. Thankfully, there isn’t any special trick to the cable other than making sure the same color is soldered to both connectors. It helped me to create a simple diagram of the colors I soldered to a specific pin.

PIN   Wire Color
6     Brown
1     Green
4     Red
2     Black
5     White
3     Orange
7     Blue

Soldering the Power Connector Together

The wire colors can vary, so the colors above may not match your cable. Also, do not accidentally wire any color to different pin numbers on both sides. This can damage the Commodore 64 permanently.

First, assemble the 7 pin DIN female connector using the wire color code cheat sheet above. However, this can be tricky since there isn’t a lot of space. Be careful not to accidentally touch two wires, or bridge solder between two different pins.

Next, use a multimeter to verify continuity between the pins and the other end of the wire. Moreover, this will test to make sure that more than one wire is not connected to a single pin.

As with the 7 pin DIN female connector, solder the wire to the pins of the angled 7 pin DIN male connector using the wire color code cheat sheet. Thankfully, the 22 AWG wire will fit inside the pins since they are hollow. This reduces the risk of accidentally soldering two wires to the same pin. However, it’s still possible to use too much solder and two wires touch.

Before assembling the protective covering, examine all the pins to make sure none of them are touching each other, and verify connectivity on both ends of the wire with a multimeter.

Testing the Power Connector

So far, so good. However, I’m a paranoid person when it comes to verifying. This is my childhood Commodore 64 that I’m dealing with, so extra caution must be taken!

With my trusty multimeter and power supply pinout in hand, I unplugged the power connector from my Commodore 64 and turned on the PSU. Using the multimeter, I tested each pin and verified it matches the expected results of the power connector pinout. Then, I plugged in the newly created power adapter into the PSU connector and measured each pin of the 90 degree end. Thankfully, the five different measurements with and without the adapter were the same.

With my paranoia in check, I connected the new power adapter into the Commodore 64, held my breath, and then turned it on.

The 90 Degree Power Adapter v1.0

Success! Just to be sure, I kept the Commodore 64 running for about 30 minutes to double check that there wasn’t a problem. After 30 minutes, the Commodore 64 was still running in all its glory. Since there was no smoke, fire, or a dead Commodore 64, I declared Victory!

Sometimes, we can’t buy something to fix our problems. Therefore, all one needs is a little time and ambition to explore the problem. Once the problem is understood, a solution can be achieved by making a plan and taking it one step at a time. That said, I have a couple of ideas to explore for v2.0!