C64 / VIC20 / C128 PSU Open Sourced

For those wondering why this exists: the original C64 PSU has a (common) failure mode after a few decades, where it will output power in such a way that will destroy the C64 (and its irreplaceable MOS ICs). If you find an old Commodore and you want to test it, don't plug it into the original PSU without testing that first with a multimeter!

Nice job finding a good source of parts for this. I might as actually build something like this.

There are few things in the PCB design that I might want to change. The live and neutral are precariously close to each other near where live connects to transformer. Also the mounting screw is very close to mains voltage. Maybe I'm just paranoid about mains voltage, but I'd increase the clearances, considering that there is plenty of board space. While we are changing the board, I'd also bump the trace widths on the low-voltage side, although I don't believe that being really a problem now.

Then comes the parts I know less of. Would it make sense to add some filtering to clean the power? I'd imagine it works perfectly fine without, but maybe to improve audio/video quality? Also the fuse is on the "neutral" side, is that good? Although the plugs around here are unpolarized anyways, so the distinction can't be very significant.

I can remember my C64 being out of action for weeks at a time (months even?) due to the power supply failing and having to wait for - I don't know what; repairs? parts? It happened more than once. This was in New Zealand in the 80s. It was a much more isolated place than it is now (and it's still pretty isolated!) so very slow to get things like this sorted (and service culture then was very poor - only slightly better now). All dealt with as warranty issues if I remember correctly, but the time it took was agonising for a socially awkward 13-year-old!

The power supply is one of the trickier aspects of getting a working C64 rig, and it's not uncommon to spend as much on it, as on the C64 itself. You'll see a lot of "no power supply, untested" C64s on eBay because of it...in my experience those are all just actually dead (and maybe known to be dead by the seller, but the well-known problem with power supply availability gives them plausible deniability...but, maybe they also tried with a PS that kills the computer, which also happens sometimes with the original power supplies).

In short, necessity is the mother of invention and what not. The Commodore power supply was a unique beast, so there are no off-the-shelf replacements, so there's been an aftermarket for them for a long time and schematics of the old power supplies have also been available for ages, though having one that doesn't have a dangerous failure mode is an improvement.

I bought one of the bare bones power supplies from here: http://personalpages.tds.net/~rcarlsen/custom%20ps.html it is indeed bare bones and two wall warts, but it is very nice. His site contains all relevant technical info and then some.

Open sourced ... with schematics files for a proprietary CAD program.

Removed comment - does have OVP