The Amiga 500 has an external “brick” power supply. And while there have been variations over the years, most of them contain a large heavy transformer and linear regulators. These are prone to fail over time, or at least need serious overhauling, and even the youngest are a good 30 years old. Mine is several years older still.
There is a solution in the form of modern switch mode power supply modules, such as those made by Mean Well.
There are several in Mean Well’s range that are suitable, the requirements being +5v 3A, +12v 1A and -12v 0.1A (the 5v supply varied between units from 2.5 A to 4.5A). Obviously a beefier supply is needed if you have more power hungry add ons. The RT-50B supplies 5A, 2.5A and 1A at the required voltages , so it has plenty of capacity.
Unfortunately due to the supply shortages resulting from the covid pandemic, these are hard to get hold of, and were out of stock “for the next several months” at the time of filming. So I went with an alternative that was available – the RT65B. This is a slightly more powerful unit (65W vs 50W), and comes in a bigger package. But otherwise it’s still suitable. I bought mine from Power Supplies Online in the UK.
Now, the RT-50 (the “T” stands for Triple, i.e. 3 output voltages) fits nicely into the A500’s brick enclosure (unless you have a “potted” version, which is filled with epoxy resin, and good only for the bin). Unfortunately the RT-65 is slightly too big, and that means a new box to put it in.
I 3D printed mine, using a design that I adapted from one I found on Thingiverse. I also reuploaded the remix so you can print it for yourselves: Link.
The cables and plugs can simply be reused from the original.