Just speculation on my part, but as modern ATX power supplies can deliver large amounts of current on the 12V rail, it may take a bit longer for the short circuit protection to kick in compared to an older unit, thus giving it more time to fry traces on older boards.

As for the 3 AT units, keep in mind that there are usually not many variations when it comes to design, most of them use the same tried & tested architecture. So you should focus on component and build quality.

Now, from those the Packard Bell one is clearly the best: well built, they didn't skimp on "optional" components like the EMI filter, good quality Japanese caps. Don't be mislead by the apparent lower power rating, if anything it's probably underrated and can do a few watts more... in any case it's more than enough for any normal AT build unless you plan to stack multiple mechanical hard drives.

Of the other two, I'd use the Holly unit but if it's going to power something you consider valuable I would probably refurbish it with new capacitors and proper safety rated X/Y caps on the line filter. The transformer is on the small-ish side, but it's probably OK for up to about 150W.

The "Solar Power" is the most dubious, anemic primary side caps, small transformer, almost non-existent line filter and "2 diodes on a bracket" for the 12V rectification. You could probably make something decent out of it but I don't think it's worth it, you can probably get a nice old Delta or Astec unit for the same money that you'd have to spend on components.

Thanks! That helped me get my bearings. The Holly tested eerily dead-on, right down the line accurate on all rails (hooked up 3 bad old Conner HDDs to get the engines firing). The Packard Bell is ~11.5 on the 12V rails, so not sure if that would affect drive operation. Not going to bother with the Solar.

TheMobRules wrote on 2026-01-27, 03:48:

Now, from those the Packard Bell one is clearly the best: well built, they didn't skimp on "optional" components like the EMI filter, good quality Japanese caps. Don't be mislead by the apparent lower power rating, if anything it's probably underrated and can do a few watts more... in any case it's more than enough for any normal AT build unless you plan to stack multiple mechanical hard drives.

Agree and well built ! It just needs a fan.

FlynnTinkers wrote on 2026-01-27, 17:09:

The Packard Bell is ~11.5 on the 12V rails, so not sure if that would affect drive operation.

11.5V should still be OK, but if you only used hard drives to test the PSU, try it with a more "realistic" configuration (such as MB+CPU+1HDD), that will provide a more balanced load which may result in voltages closer to the nominal values.

In any case, that PSU also has a trimmer resistor that you can adjust with a screwdriver (use a plastic one and be careful if you do it with the unit on!) to fine tune the voltage. Keep in mind that it will probably affect both the 5V and 12V rails, so be sure to measure both after adjusting.

Group regulated, so if you only test load the 12V, it will sag and the +5V will rise