Generic PC components are astonishingly cheap, due mainly to economies of scale and the continuing demand for the newest and greatest. This gives a lot of opportunities for anyone with an interest in tinkering. Take for example the PC power supply unit. Since the introduction of the ATX connection standard about 20 years ago, pretty much all PSU boxes have been interchangeable, differing mainly in things such as total power, quietness, length of cables and quantity of extra connectors. This has driven the price right down, but all ATX compatible PSUs provide at least 3.3V, 5V, and +/- 12V and they all provide copious (in microelectronics terms, at least) current
As an example, I bought a 550W “Alpine Silent Power Supply” for under a tenner from Scan Computers which makes barely a whisper when running and provides at least 20A on every output except -12V!
I toyed with the idea of just hacking away at the case to make a usable bench power supply, but then I found a neat “ATX Breakout” board from Dangerous prototypes
I ordered one, together with its acrylic “case” and assembled it in minutes. The end result is very pretty, and does have some advantages over wiring straight in to the PSU: There is an ATX power switch on the board which correctly starts and stops the PSU; resettable polyfuses on each rail, handy indicator LEDs on each of the outputs and two LEDs indicating mains power and output power active. The main downside is all the excess cables flopping about, so I may just remove them. I am also considering mounting the board on the side of the PSU enclosure, to make it into a more portable and usable piece of bench equipment.
I know it’s not a proper bench tool. It has no controls or voltage/current readouts, and it may well be less robust in the face of inadvertent shorts or over-current problems, but it is certainly cheap!