I needed a quick and cheap way to get -5V available on a modern ATX PSU. The current requirements were risible, so I just made an inline module that takes -12V and regulates down to -5V using a simple and cheap 7905.
I take NO responsibility for what happens if you decide to build and use this device. Your computer might crash, catch fire or be destroyed in other nasty ways.
| Component | Qty | Type / Value |
|---|---|---|
| J1 | 1 | Molex 39-30-1200 |
| J2 | 1 | Molex 172708-0020 |
| Pins for J2 | 20 | Molex 172718-1111 |
| U1 | 1 | 7905 (TO-263) |
| C1 | 1 | 10uF/16v 1206 ceramic |
| C2 | 1 | 100nF 1206 ceramic |
Cut away the excess plastic from the Molex 172708-0020, fit in all the pins, and then slide the PCB between them. Then solder them, making sure they don't touch.