Category Archives: Uncategorized

Silencing a screaming network switch

Sometime ago I bought a used Planet WGSW-24040 network switch from eBay.

It is a discontinued model. Nevertheless, it has some features which I think is pretty cool, especially for a home network. The switch has 4 x SFP ports and 24 x gigabit ports. Too bad it is not a PoE switch. It is a layer 2+ managed switch that supports static Layer 3 routing; It supports VLAN, Link Aggregation (LAG), Multicast, QoS, SNMP, etc. Certainly has all the bells and whistles I would want in a switch.

For the price I pay for it, I am well pleased…….except one annoying “feature”.

The switch has a cooling fan which is LOUD to say the least. For a long time I have put up with it; then one day I decided to dismantle the switch to have a look at this annoying fan.

Exhaust fan

Several quick observations:

1. It is a 40mm dia. fan. Depth of fan is about 20mm. The depth of the fan is an important criteria because very often 40mm fans are pretty deep and this may not fit within the switch.

2. It is a 5V fan. DC obviously.

3. There are only 2 wires to it. So that means the switch has no way of telling what is the fan speed. You will need a third wire to achieve that. There is also no way to control the speed via PWM; To achieve that you will need yet another wire.

But is it all that bad. The switch itself has no “fan speed control” features anyway so there is absolutely no benefit to have a 3pin fan or 4pin fan.

I am aware that some network switch uses 3pin fan and if you replace the stock fan with something else which rotates at a different speed, the switch will tell you there is a fan problem, even when you don’t have one!

So the fact that my switch has a stock standard 2pin fan is actually good news, at least to me.

So now I can go source a 2pin fan which is quiet.

So after practicing some google-fu, I quickly come to the conclusion that I really wanted the Noctua NF-A4x20 5V fan.

Here is the link to this fan: https://noctua.at/en/products/fan/nf-a4x20-5v

I bought this from PLE for $24. A bit pricey but for something that runs 24/7, I thought…why not.

So with the stock fan replaced, this is what the installation looks like:

WP_20180125_19_13_38_Rich

WP_20180125_19_14_05_Rich

With the Noctua fan installed, the loud fan noise is now gone for good. The fan is practically silent even at full speed. I have not observed any heating issues and the switch has been stable since the fan is replaced.

Overall I am happy with this simple modification.

If you are intending to do the same fan mod, be sure to do some study to get the right type of fan. Hope this post helps you.