Hello

I'm currently working on a Windows XP era machine and the PSU that came with the case has been a bit of a headache for me. It's proprietary, so I can't just easily replace it (I've spent a few days trying to find my specific model to no avail). It soon dawned on me that, although I was at a great age to learn about computers during the late 90s/early 2000s, I never really cared to learn about computers until the mid Windows 7 era. Although I can figure my way around the operating system, I don't have much real experience with that era hardware, especially when it comes to troubleshooting issues.

I figured I'd try to see if maybe I could get some insight about my current PSU issues while also maybe asking for sources of any informative guides/troubleshooting posts that would be worth me reading through.

Current Issue: My PSU has been random in when it wants to operate properly. Before doing any troubleshooting, it turned on twice (since purchasing the computer) and on the second run I could hear the fan slowing in the PSU slowing down and eventually the computer just shut down. I disconnected it and used a modern PSU in the time being to go through the hard drive and update any drivers before seeing what I can do with the machine. I soon realized that the machine turned off after I added a 2TB mechanical drive (originally came with a 300GB mechanical drive and also worked with a 500GB SSD), so I switched it back to the SSD before switching it back to the original drive (I was hoping to try and archive the original contents of the drive). After removing the 2TB, I was able to get the original drive back on. Since, it's randomly not powered on twice. No noise and no fans (from the CPU or PSU) spun up.

I have taken the PSU apart to see if any caps went bad, any solder joints were in bad condition, any wires were ripped or maybe if something was off. I didn't see anything that stood out to me (although I'm not 100% sure what I should or shouldn't see). I have since replaced the original 90mm fan with a newer 90mm fan but nothing. I plan to try and get everything back in the computer to it's original state to see if that'll work, but it be a shame as so many things could use a modern upgrade to keep it going for another few years.