First post here - love this community already and lots of helpful posts on modding for less noise. Have to run a small lab for VMware certs out of my home office and replacing a stack of 3750s with a 7250-48p and 8x licensed 10Gb ports. Already that is quieter, but not enough for me to be happy yet. I've read all of the fan mod threads multiple times and essentially it seems that there's a comedy of issues with the fan mods leading to people using wood screws to wedge fans on top of the ASIC heatsink to cool it down after putting in slower fans - otherwise the system might ramp up to speed 2 indefinitely or might switch between speed 1 and speed 2 relentlessly since slower fans move less air and cause the ASIC to go to speed 2. Top this with the fact that it sounds like the board itself requires a minimum RPM to boot and you can either put in fans that meet this RPM or you can spoof the signal - which is also quite tedious.
Annoyed slightly by this issue, I started thinking about re-applying thermal paste - because I didn't quite understand how my switch could idle at 58C on the ASIC with 68-70F ambient temps when I literally only had a serial cable plugged into it and nothing else. I think the thing deterring people from doing this is that it's very difficult to do without damaging the switch. The heat sink is mounted with push pins that typically require you to have access to the other side of the board to get them out. Once the pins are in, they're not coming out without some serious persuasion.
So I tried to take the circuit board out only to find that it's literally riveted to the switch chassis and practically impossible. What followed was almost 60 minutes of me trying to get these things out without damaging the circuit board. I think I may have been successful overall. I had to remove everything down to the board to work in the space. Small warning- the fins arekind of edgy - I sliced my finger tips twice getting this out proceeded by dousing them in alcohol when I was cleaning the junk off the heatsink/asic.
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And what I found is in my opinion utter stupidity. If you've applied thermal compound to a heat sink before, you know that the best practice is a very thin layer of compound to aid the transmission of heat. Too thick and you lose effectiveness. CPUs call for a compound the size of a grain of rice. What I found left me dumbfounded that this is how this equipment was designed. Perhaps I'm missing some of the finer details of enterprise switching...?
Pre-cleaning
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Post Cleaning
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Board after the fact - you can see a little scratching around the holes, but that should be fine given they're no circuitry there.
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So I'm in a spot where I'd like to put a better heatsink on here - preferably one with a small fan integrated. The problem is that the heatsink literally doesn't have a part number and I cannot find any reference for the size / compatibility. I measure it to be approx 65mmx70mm 10mm fins and 2 push-pin mounts. There's nothing out there that fits the bill ... everything on digi and a few other sites are mostly square.
So I might just have to reapply paste and mount the heatsink. I think I have to replace the push-pins as I kind of mangled them getting them out - not really an issue as they're cheap I believe 3MM, and I can put slightly stronger springs on them this time around if I have to go that direction to improve contact with the ASIC.
Anyone know where I can get specs on this heatsink? I imagine re-applying good paste to the heatsink (like MX4 thermal compound or ceramique) could go a long ways here to improving temperatures given the previous situations.