Hello, just wanted to share a small project i did for a friend. He has built a pretty crazy oldschool computer for playing dos and early windows games, based on a dual socket 370 motherboard from epox, (one of few boards with this setup with an ISA slot for your soundcard), 3dfx voodoo, and voodoo 5 5500. He wants however for it to me completely passively cooled, and in a rackmount case. Which with a solid top panel is pretty much unattainable. I will be making another top panel for the case with good ventillation, however first thing to do is to upgrade the coolers. That is a challenge for few reasons, first is that the stock mounting on socket 370 is designed for very small light heatsinks, only thing you can mount the heatsink to are the tiny plastic hooks on the edges of the socket. Even with a bit bigger chipset heatsink mounted on the cpu, My friend had those fail on him during transportation of the machine.
So this mounting solution is completely not acceptable for anything bigger. And these heatsinks were already undersized for passively cooling tualatin cpu’s. (those are sitting in a so called “lin-lin adapters” which are basically a socket that you put into the original socket, to swap few pins allowing a tualatin cpu in a coppermine compatible board. That is some extra challenge to mount the coolers again, because of the added height. So after a bit of thinking, i realized the only possible mounting spot are the motherboard standoffs themselves. Four of these closest to the cpu, this is what i eventually came up with:
These blocks on the drawing are heatsink bases. I bought two silverstone heatsinks rated at 130W, 90mm fan size as the rack case doesn’t allow for a taller heatsink. This should be enough for running without a fan for such a cpu. The mounting plate has holes for self-clinching standoffs, with holes for an m3 screw. You can screw down the motherboard as usual, except four screws just have to be longer as they will also hold the plate. This will be all clear on a picture:
Mounting plate also holding the motherboard down with longer screws, going into factory case standoffs:
It was tight to make clearance for the RAM, and the atx power connector. The square holes are there to not interfere with VRM and chipset cooling.
Everything mounted up solid. I haven’t given it a proper bench yet, but that will be coming when i get a bit of spare time from other projects.