2.9L Compact m-atx / itx pc case - Mini PC - customizable

The case..

The case can be printed on a standard ender 3 bed (235x235mm), the largest dimension is 234,30mm (very tight fit). I chose this dimension to enable printing the case in fewer pieces with a single solid base.

• However, not all m-ATX boards fit; only those with a smaller size than ASRock H610M-HVS/M.2 R2.0  so less than 22cm*19,3cm.

No supports are required, except for one part of the exhaust air duct, named duct1

The case uses a standard I/O bracket, but it needs to be trimmed slightly to allow the screws to be inserted. The cut is not visible once the shield is installed.

Cooler

I removed the fan from a stock 12th Gen Intel heatsink and replaced it with a radial laptop fan that pulls air through the heatsink. The hot air is ejected out the back through a 3D printed ventilation duct. Fresh air enters from the front, cooling the Pico PSU and all the components around the CPU. Heat generation is limited by the CPU's low power limit.

The fan is PWM-controlled for low-noise, nearly inaudible operation under light load.

PSU

External 12V power supply with a cheap AliExpress pico PSU. A 65W adapter can provide enough power for a 25W CPU power limit. With a higher-rated PSU, the bottleneck becomes the heatsink — around 45W continuous load, or more for short durations.

I added some heatsinks to the PSU to hopefully extend its lifespan. I also disconnected the Power Good signal — it wasn't complying with ATX standard timings, which caused my specific motherboard to refuse to boot, although other motherboards worked fine.

Why?

This is an updated version of a previous case I designed. I know that it's too small for HDD storage, a dedicated GPU, an internal PSU, better cooling, or extra fans. There are downsides.

I simply wanted a compact case, like a mini PC, but built around cheaper M-ATX boards (ITX ones are a bit expensive)  with front fresh air intake and rear hot air exhaust. It's not the best case, but it does what I wanted for my Proxmox server.

Stuff to be improved

• Improved cooler with dual radial fan support

• Low-profile GPU support

• Additional front I/O options: USB, USB-C, small OLED display

• Add support for 2,5 inch hdd (alternative to gpu)

• Change the screws' position to avoid require cutting mb IO shield

Required Hardware

• Flat head M2 screws

• M2 brass heat inserts

• 6× M2.5 screws (for motherboard) + M2.5 brass inserts

• Pico PSU, Intel 12th Gen stock cooler, ITX or compact M-ATX board, radial fan, power button

• 8 magnets for the cover, 5 mm diameter, 4 mm height

Yes.. I'm using a server power supply for the mini-PC. It's a 1.3 kW 12V Artesyn

I modified it with an extra heatsink on the primary fet, a Noctua fan, and a Microcontroller for fan control based on temperature. It can't hold full power due to the reduced airflow, but has no problem for this usecase