The Monoprice Mini 3D printer is a fantastic machine. I'm a fan, and so are many others. But being a low-price machine, it understandably comes with a few cut corners.

One of the most notable issues is with keeping the control electronics inside cool. They are fully enclosed in a sheet metal chassis, with no active cooling and only a pattern of vent holes on the bottom. Way less than ideal.

This makes it pretty easy for those control electronics to overheat, which can introduce faults in your prints. The most common type of fault is the dreaded "extruder skipping." Keeping your controller cool is the best way to prevent it. Just stirring the air inside the case slightly can have a huge effect on PCB temperatures.

The design uses a carefully-selected low-profile fan, so it can mount to the pre-existing vent hole pattern. It uses a patch/splice dual connector to deliver power to the fan without having to solder to the board. This makes the upgrade 100% reversible.