Hi everyone,

Like many people here, I have quite a few machines that either need a new PSU already (or will need one any day now). I find myself trying to learn circuit troubleshooting and repair just to keep my machines alive in the future. It's a pretty steep learning curve for someone just wanting to keep their machines humming along...

So I had a thought- Having seen how so many open-source hardware projects have recently created such amazing things as sound and video cards, even an entire functioning XT board- what if we could create a modular "universal" switchable power supply? I'm thinking something that could at least output 150-200W. But since it's modular, one could have different specs for different wattages...

It could consist of two separate components:

1. A daughterboard that had all the switchable PSU components on it. It would have a row of pins on each end of it that carried all the +/-5v, +/-12v, and switch connectors, and allowed it to be "plugged" into...
2. A PSU adapter board that would be made for each PSU type you could imagine. It's basically a blank board that allows the daughter board to plug onto it, while fitting into the old PSU's housing and providing solder points for attaching the old PSU's external wires, or even work in systems that use edge connectors (like many IBM PS/2 models)

So what you'd have is a system where the complex part is designed and built only one way, and then for each unique system you'd simply create a very simple adapter board for it, that would fit into the original PSU's case.

This would allow old hardware to be able to have new reliable power supplies, fitting inside the original casing. I imagine it would be likely that the new PSU could offer better filtering and power quality that also would help preserve other components in these aging systems.

Like for myself, I have a Compaq 386/33L who's PSU fades in and out. Replacements are unobtanium. I also have some WYSE 386 machines with pretty exotic non-standard stuff going on. If something like what I'm describing existed, myself or anyone could design the adapter board for the PSU, share the design. Anyone could build a functioning PSU for virtually any system once the adapter board is created. To start off we could design boards for the usual suspects-- the original XT and AT power supplies for example. We could even make the PSU board compatible with ATX setups as well. New PSUs aren't exactly drop-in replacements for the PSUs from the late 90s early 2000s either. Especially the proprietary ones. NOS units are over 20 years old now. The PC turns 40 this year, XT 38, AT 36. 486 systems will all be 30 years old in just a matter of a few years... I digress...

So what do you guys think? I can help in anyway possible (funding for example) but I'm still a beginner learning how to do my own repair work. I certainly am not skilled enough to design a switching PSU from scratch, but it seems like many of you here may be? What do you all think of coming together to create such a thing? I know the benefits of something like this could extend well beyond just old PCs, but other old retro hardware as well.

First questions that come to mind:

• Is this idea old and redundant? I couldn't find mention of anything like this here before...
• How small can a 200W switchable PSU be made to be using modern components?
• If it's still big would we need two form factors to accommodate the square and long PSUs? (Think PC/XT/AT vs. PS/2 or old Compaq)