The Commodore 64 power supply was the problem here. These original bricks are known for failing in a way that can damage the computer, and a lot of people just throw them away. I rebuilt one using the original case, and Penny showed up right at the start to supervise.
Before getting into the rebuild, I went over a few alternatives. I showed replacement supplies from Ray Carlsen and Keelog, mentioned the New Brick, and also pointed out saver cables as another option if you want some protection without opening anything up. I also gave credit to Jan Beta for rebuilding these in third-party cases, and to Kevin Ottum for showing a method that reused the original Commodore case.
I had two supplies on hand, including one I had already rebuilt, and I weighed them to show how much of the original weight came from the potting compound. The original unit came in at 1,378 grams, while the rebuilt one was much lighter at about 1 pound 6 ounces. I also compared the black and cream versions and noted the printed output ratings on each.
The rebuild used a 9VAC wall transformer and a 5V 3A Mean Well switching supply, along with epoxy, a fuse holder, and an LED. To open the case, I worked a large tapered screwdriver into the openings where the cords entered and slowly pried the shell apart. Once the lid was off, I cut the wires close to the potting to save as much cable as possible, removed the cords, cracked the potting loose, and knocked the whole block out of the case using two pieces of wood against the molded fins.
The 9VAC adapter was too bulky in its plastic shell, so I cut the case off with a Dremel and removed the wall prongs. That left the transformer small enough to fit inside the original Commodore housing. I cleaned the case, drilled a hole for the LED, broke off the internal posts, and did a dry fit to work out where the transformer, switching supply, and fuse would sit.
Wiring took a little planning because the components had to mount in the top half of the shell to leave room for the cords. I connected mains, earth ground, the 9VAC output, the 5V output, and the LED with a resistor. On the bench, the rebuilt supply tested at 5.1V DC and about 10.63V AC unloaded, and I noted that the 5V supply could be adjusted with its onboard trim pot before everything was epoxied in place.
Once the epoxy cured, I installed a 4 amp fuse and glued the LED into the case. Then I traced the original Commodore cable with a meter instead of trusting wire colors. The two upper pins at the DIN plug were 9VAC, the bottom pin was ground, and the offset lower pin was 5V. After connecting those wires, adding heat shrink, and trimming a little plastic for clearance, I closed the case and checked the outputs one more time.
The rebuilt supply powered up a Commodore 64 without any trouble, and the machine came right up. The finished brick kept the original look, added a power LED, ran cool, and was sealed with a little E6000 so it stayed together but could still be opened later.
— Aaron
Links
- 5V 3A Mean Well Power Supply
- 9VAC Wall Transformer
- “Fakebit World” and “Cheese Brickwall” by Malmen
- “Noisette Part A” by CL Collaboration
Timestamps
00:00 – Intro
01:17 – Alternatives To Rebuilding
06:40 – The Plan And Tools Needed
15:00 – Removing The Potting
22:35 – Wiring
28:06 – Initial Test
34:38 – Epoxy and Fuse
39:44 – Tracing C64 Wires
44:11 – Final Test With A C64
46:03 – Wrap Up