HP breakout board for the Common Slot power supplies. Similar to Jboards design, however I added a header to remote control the power suppy via a ESP-01 relay board and a buck converter.

J4 is a standard 2.54mm pin header.

Pin 1 - Power On - Ground to enable power output. Pin 2 - Vsb - 12v standby power - run this to a 5v buck converter (like a Pololu D36V6F5) then to your ESP-01 Pin 3 - Ground

R1 is a 21k or 22k 1/8w

Card edge connector (that plugs into the HP Power supply is a TE 1761469-1 https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/1761469-1/1761469-1-ND/2688514

Power screw terminals are 6.35mm 2-connector screw terminals - make sure they are 32a rated. I use Phoenix contact 1714955 https://www.digikey.com/product-detail/en/phoenix-contact/1714955/277-1269-ND/260637

All of the connectors mount on one side, as indicated from the PCB text. MAX power is 900w with 1oz copper. You can run it on a HP 1200w power supply fed by 120v. DO NOT go over this. at 900w, the PCB will run warm. You can run 2oz and have less heating.