This started out of annoyance that I had to have a separate PSU dangling outside my Prusa-Box printer enclosure for fans, LEDs and Raspberry Pi. On top of that the Silver PSU cover has no keystone opening, only the Black PSU cover has it, and I didn't want WiFi-only operation.
So instead of the 12V → 5V buck converter I've decided to find a decent 12V PSU that could power everything while fitting inside the rather constrained PSU cover. And since only the Raspberry Pi wants 5V I've decided to opt out for a smaller buck converter that can be placed inside the control panel.
Stuff I found that works best from AliExpress:
The included FreeCAD project allows moving the mounting posts in case the GaN PSU isn't available or another is preferred.
I used Prusament Orange PETG with “0.2mm QUALITY” preset modified to generate organic supports on build plate.
Before mounting the embedded PSU it has to have input and output wires soldered to the PCB. The input may be 18AWG (0.75mm2), the output should be at least 16AWG (1.5mm2) with the appropriate insulation voltage rating.
After mounting the PSU the wires are cut to length and crimped. The output may be terminated with ferrules, the input should have spade terminals similar to those used by the printer PSU connectors.
Live and neutral wires are connected to the corresponding printer PSU screw terminals. The output is connected to a WAGO connector that routes 12V to every consumer.
After connecting the PSU and securing the cover to the Prusa-Box a keystone socket is placed in the corresponding opening and one can start routing 12V and 24V cables to the appropriate consumers.
The author remixed this model.