Commodore 64 New Powersupply

I purchased an old Commmodore 64 Breadbin style computer in December and it didn’t come with a power supply. That is not exactly a bad thing as the old power supplies are responsible for killing alot of C64s over the years. When those supplies fail, then start sending to much voltage into the 5Volt line burning out chips on the board. To see if it made sense to try to bring this old C64 back to life, I hooked it up with a 9Volt Ac Transformer I had and my regulated variable power supply. It sort of worked, it did need repaired, and that will be a post for another time.

I did get the C64 repaired, so it was time to make a proper safe supply for the unit. I took my 9Volt 1Amp Transformer (well 9.5Volt ) and picked up a new Mean Well RS-15-5 5Volt DC 3Amp power supply. I also picked up an enclosure, 4 conductor wire, and finally a proper DIN power connector from The other items I had around, the IEC power jack, power cord, fuse holders etc.

I cut and opening in the back for the IEC power port. I also drilled the front for the outgoing power cord and installed a rubber grommet to protect the cable. I used my small drill press to start the holes then for the IEC being obviously not a circle, I trimmed out the rest with my Dremel and a hobby knife. The material the case is made of is reasonably soft and not too bad to work with. Just don’t try to drill or cut to fast, let the tool do the job.

The bottom of the case had some standoffs for mounting. I cut a piece of raw circuit board material I had laying around to fit into the bottom. I then drilled holes to put screws into it to hold it to the standoffs. This let me have a solid base to attach the heavy transformer and power supply to without putting holes through the case itself. I then mounted the Mean Well supply and the Transformer to the board and installed it into the case.

In the top I mounted a fuse holder, and later a power switch beside it. All of the exposed connections were sealed with Liquid Electrical Tape on the IEC port and the little bit at the base of the Fuse holder that wasn’t covered by the heat shrink for added protection if someone ever opens it up. I also cut out a fairly large opening for ventilation. I figured if I was going to open it up, I might as well make it worthwhile. I had a piece of screen from an old computer case and cut it down to fit and shaped it to bulge into the opening. I don’t know that much heat will be generated, but it certainly should have enough passive cooling going on with that much ventilation. The grill is pretty small, so the odds of anything falling in should be minimal. Also with all of contacts well insulated it shouldn’t be a problem. Something could get in the screw terminals on the Mean Well maybe. To put in the Grill started by drilling in the corners for the opening with a Forstner Bit with my drill press to make the rounded corners of the hole. I then cut the rest out with the Dremel to get it close and then a utility knife and such to try to keep it clean and strait. It is slightly out of square, but still looks pretty good overall. Of course I did test the supply before attaching it to the Commodore 64.

Here is the completed supply after I added the power switch.
Here is the supply after I finished assembly on the Commodore 64.

It was a relatively simple project. It also was not very expensive overall. The Mean Well was pretty cheap I believe $10.00 with shipping. The next was the case which was around the same price. Actually the 4 conductor wire was more than either of those, I ended up with a good bit of extra, and it is not very flexible. I don’t like it that much, but I wasn’t wanting to spend $20 or more. The wire I used is a stranded alarm system wire, while it is stranded it is only a couple strands and not very flexible. I would also probably crimp badly if i wrapped it up. I figured if the wire becomes an issue, I will end up replacing it with a more appropriate wire. Overall I may have not saved all that much money making it myself compared to the cost of some of the units available theses days, but it certainly means more to me knowing I made it myself. There is not a Commodore 64 Saver circuit in it, but the Mean Well supply does have protection in it. I have purchased a Commodore 64 Saver kit that I thought of possibly adding to the unit, but I don’t believe I have enough space in the case to get it in there. Maybe if I replace the circuit board with an etched board that the Saver circuit was built into..

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