Silencing Network Switches

Not everything can (and should) be done via wireless. In fact, if it is something related to security or reliability, good old Cat5 is still your friend. This results in a rather expected gigantic cable octopus and one or more switches. This is the point where IT traditions and best practice command that the infrastructure is aggregated onto a smaller number of switches using vlans if need be. That is also the point where things get eye-wateringly expensive.

While a small 5-8 port Gigabit switch costs ~ 10£ on Amazon, 20+ port managed ones cost in the hundreds and most of them suck. Anything from the 2nd and 3rd tier vendors has atrocious buggy software and makes your network less reliable, not more. The big guys like Cisco, HP or Arista know this and quite happily ask 200£+ for their wares. That leaves only one choice - eBay. There is plenty of 5-10 year old gear on eBay which will do nicely as a home infrastructure or a Lab switch. Unfortunately, all of it has the F-word: FAN. Noisy, ugly 40mm buggers by Delta electronics +/- a custom connector. In most cases it has no speed/airflow management whatsoever resulting in a constant 24x7 source of never ending racket.

It does not need to be this way. Granted, the modifications to make a switch or small router quiet are not reversible. They are definitely worth it if you are using it for your own needs.

Determine Fan type and Voltage

This is usually fairly easy. Nearly all of them are standard Delta electronics parts. Open the switch case, take the fan out and check its part numbers via Google.

This, for example is an HP V1920-24G. HP model JE009A/B. A fine piece of hardware available on eBay for 35£ and retailing new/refurbished ~200. It's downside is a 5v buzzy bee which attaches to the hole on the right and blows right to left across the power supply and the mainboard.

More About the F-word

Let's try to boot the switch with no fan whatsoever. In the case of V1920, the test passes. The switch is warm and will probably go way too warm if left without any forced cooling. It complains that the fan has failed, but works. This is normal for most enterprise switches - they will shut off on temperature, not on fan missing. This is different from let's say large ToR (Top of Rack) switches which will consider a missing fan a critical failure and will not boot without it. Older Cisco Catalysts, Foundry, Extreme, etc are all similar to this HP. Some use 12V, some use 5V fans. All are 2-pin or 3-pin with the 3rd wire reporting RPMs. Some of the newer ones are PWM (as in modern PCs), just very high rev and small size ones. Nearly all use weird connectors to connect a standard low cost OEM part so they can charge you an arm and a leg for it.

Chosing the Cutout Location

Airflow is nearly always rear to both sides in all but HP which has airflow left to right. As a result the next (rather irreversible) step is different for let's say a Catalyst and an HP. The Catalyst should be drilled in the middle, while the HP should be drilled on the right (over the area where the power supply is). Note - the actual lid has been turned 180 degrees for the picture.

Now all we need is to solder a decent fan which will start at 5V like for example most Arctic Cooling fans to the original connector from the Delta Buzzy Bee and screw it to the lid. The old hole from the buzzy bee needs to be closed with ducktape or something similar to ensure correct right-to-left airflow.

End Result

The fan is spinning at ~ 700 rpm, there is no audible sound whatsoever. While the switch is complaining that it has a fan fault it is happily working and moving around the packets in my lab. All in all - 40£ (if you source the switch off eBay) and 30 minutes of work.