You need an ATX power supply from early 2000s which output -5V. Or you can build a circuit to convert -12 to -5V.

https://www.powersystemsdesign.com/articles/t … oltages/37/9756

There is also the Voltage Blaster: https://www.philscomputerlab.com/voltage-blaster--5v.html

all you need is LM7905, thats what Voltage Blaster uses. Re: AT pico psu.

rasz_pl wrote on 2023-09-09, 01:02:

all you need is LM7905, thats what Voltage Blaster uses. Re: AT pico psu.

Agree ! and use the -12v to feed it.

This one might be the cheapest option.

https://www.youtube.com/watch?v=b2XOo_8uzvw
https://github.com/scrapcomputing/voltage-blaster-mini

Thanks, that should be super easy to build. I went rummaging under the stairs through my old stock, and found two first generation Sparkle (SPI) ATX power supplies. The oldest one actually has the -5v rail. The other is a micro ATX psu with the -5v rail, but when I hook the microatx up to my 486 board using the converter, I get nothing.

I will try the SPI one with -5v now, that should get me up and running with the sound blaster 2.0 !

Looks like I will need to replace the caps on this psu before plugging it into any motherboard.

I have a similar tester and you should hook up a harddrive to one of those molex when testing, some testers do not draw enough current on old PSU's for the rails to be stable....

It’s strange. The matx psu works fine in the matx board, and the internet says it should work the same as an ATX power supply with lower wattage . Yet when I plug it into the psu tester or a 486 board using the converter, I get nothing. Was really hoping to use it since it has the -5v rail (white wire)

The voltages on the sparkle aren't necessarily bad. The +5V and +12V look ok. You should connect a proper load to it. It may very well work to power a motherboard right now. Then you can check the -12V and -5V with a volt meter, and all the other supplies. It wouldn't hurt to inspect the inside of it, if you know how to be safe.