Hi, my 3d printer psu fan gave up the ghost, and I wanted to replace it. It was pretty noisy, so I thought about upgrading from a 30mm to an 80mm fan. I am designing the top case with mounting holes, and want some input on where to place the new fan. The original placement is the box with the red color. The green and blue box are some options I thought of for the new fan placement. Would placing it over the busier part of the pcb yield lower temps, or is that a bad idea? Does placement even matter for psu fans?
The new fan has higher airflow, but lower static pressure than the original one, and the plan is for it to always spin at a low rpm and occasionally speed up when the psu detects a high temperature.
The original config runs it completely fanless until the psu reaches 50c and only then does it send voltage to the fan header.
It looks like you would want an even airflow through the whole PSU. The main heat-generating components are using the sides of the housing as a heat sink. I'm guessing the fan is mostly so the air inside the housing doesn't get too warm, not to cool individual components.
Where is the original air exhaust? If it's near the bottom of the picture, that would confirm my theory. In that case, I would keep the fan placement as close to original as possible (i.e. the blue square).
