l00nix's RPi blog My RPi musings and projects

CM4 Heatsink Update

In a recent post I mentioned that I ordered heatsinks for some if my Raspberry Pi Compute Module 4s (CM4). Well, they arrived but I am running into some issues fitting them onto the CM4s. It seems the M2.5x16mm Screws the heatsinks come with are too short to fit my CM4 - Less-is-More (LiM) Carrier Board configuration.

The 16mm screws pass through the heatsink and the CM4 module no problem but when adding the nut to screw the heatsink tight to the CM4 module there is not enough space for the nut between the CM4 module and the LiM Carrier Board. The screws are also not long enough to pass through the LiM Carrier Board.

Heatsink 2 PIC1 - Heatsink srew clearing the CM4 module

Heatsink 3 PIC2 - Heatsink screw clearing the CM4 module sideways

I ended up ordering 20mm M2.5 screws in the hopes that the extra 4mm will clear past the LiM Carrier Board and allow to screw the heatsink, CM4 module and LiM Carrier board together.

I will keep you posted when I receive the longer screws and post pictures when it works.

Until then.