This project gives a whole new meaning to DIY PC. We don’t know how capable you were as a teenager, but could you have designed your own Ryzen-based mini PC?

Whilst making repairs to laptop internals, [Dominik Baroński] was busy taking notes. Modern super-integrated laptop PCs have reached the point where all the functions of a complete PC are embedded in a single chip. But it’s a big, complicated chip with very specific feeding and care needs. Once you’ve figured out what it needs, it ‘merely’ remains to supply it power, hook up some DDR4 RAM, PCIe storage, and some USB ports, and you’re away. It sounds easy when you say it like that, but do not underestimate how difficult it is to create such a board—or even to populate it by hand—yet that’s precisely what [Dominik] has achieved.

The PCB rear hosts a single DDR4 Dimm and an SSD.

The first video is a time-lapse of the soldering process, which isn’t very interesting beyond the fact that they didn’t even waste time making a solder paste stencil and just ran with manual tinning and hot-air reflow. Well, we guess it works, but you wouldn’t want to build a whole batch this way! Anyway, the second video, produced by YouTuber [Coleslav], is originally in Polish, but auto-dubbed to English for the rest of us, and whilst a bit long-winded, does give a flavor of how [Dominik] approached this project. There are quite a few interesting little technical details that [Coleslav] has teased out of [Dominik] when interviewing them for the video, such as they noticed that certain laptop manufacturers were reusing older PMU circuits designed to power DDR2 RAMs by tricking the controller into operating at lower DDR4 voltages by tweaking resistor values, rather than specifying a ‘proper’ (i.e. more expensive) DDR4 compliant device and redesigning the circuit. [Dominik] relied heavily on the Saturn PCB toolkit for calculating differential pairs and other physical PCB aspects to make it possible to design the circuit in KiCAD with just six layers on a minuscule 100 mm x 100 mm outline. Quite a feat!

The CPU is hot air reflowed on top of a PCB preheater.

There were issues with using certain chips that were available to buy, but the documentation was leaked, so the seller was likely not authorized. But the biggest problem is the BIOS, which was duplicated from a similar laptop. [Dominik] hopes to find help to get coreboot running on this board, at which point the archaic keyboard and system controller (now called the EC) can be junked in favor of a more hacker-friendly STM32 setup.

No PCB footprint for the Ryzen chip was available either. [Dominik] created it using a Python script that read the SVG view of the ball-out downloaded from the WikiChip site. The pad positions were known, but the names still needed to be entered manually. All 1140 of them. Once the mappings were entered, schematic symbols could be generated to complete the schematic. Next, they created a 3D model using ChatGPT to write a Python script that read in the ball positions and spat out an STL file that could be molded into a complete footprint! [Dominik] has made a short write-up on Hackaday.io with a few images, and hopefully, more details will appear in the coming months. We’ll be keeping an eye on this young maker over the next few years; we have a feeling great things are coming.

Whilst we’re on the subject of building PCs, here’s a DIY gaming laptop with a twist. At the other end of the complexity scale, here’s a neat DIY computer built from scratch.

Thanks to [JM] for the tip!