Fan speed control on Zyxel switch?

Waffles779

Thank you for the images, they are helpful. It looks like I have the V1.

Fortunately, I was able to rewire the fan header on the new fan and make it match the OEM fan. It works perfectly and is much quieter. 

I don't think fanless is a good idea after seeing the inside of my switch. There is a heatsink that gets pretty toasty to the touch
(it won't burn or anything but it's uncomfortable after a few seconds)

I don't know the OEM fan specs, but it doesn't seem to matter all that much to the switch. It'll operate with or without a fan and has no way of telling apart one fan from another. The RPMs are not listed on the fan or in the software, so I can't say I have a matching fan but it's certainly quieter. (didn't require any mods either besides correct wiring)

For owners of the V1, a quieter fan is about $7 and 10 screws. Fanless is not a good idea unless you have other airflow to offer such as leaving the switch open with maybe a 120mm fan (120s are very quiet) pointed at it. This thing NEEDS some kind of airflow to maintain performance. 

andreaswollmann

Hello,
I have, among other things, a GS1920-24HP V1 switch.
Firmware version V4.50(AAOC.3) | 05/20/2020
The fans have 3 pins.
I can't find any option in the menu to switch on the fan speed in a temperature-controlled manner.
What am I doing wrong?

I thank you in advance.

Andreas Wollmann

StefanZ

One solution would be to plug an external controller between the switch and the fan.

Ideally this would have a thermistor and power the fan accordingly.

I personally would solve this problem with a microcontroller, a PT100 sensor and a mosfet.

If you don't suck at analog electronics – like me – you could also use a PTC/NTC, some resistors, an opamp and a transistor.

Or just buy it for some bucks: https://www.aliexpress.com/item/1005001581225565.html

Depending on the fan model you also might have digital RPM out to work with.

andreaswollmann

https://community.zyxel.com/en/discussion/comment/62728#Comment_62728

I am an embedded software developer ;)
I am familiar with analog circuits at a low level.

Actually you would have to read ALL temperatures from the controller via SMBus / RS232 and control the fan speed accordingly if necessary.

Alternatively, you can load the switch and then look in the switch display (or with a thermal imaging camera) to see which component warms up the most. And use this component as a reference for an analog fan control.

My problem: I don't have time for this fun project.

And on the other hand, it makes me sad that the devices in this price range don't have a fan control.

StefanZ

The manual for the v2 has the positions of the sensors: "BOARD / MAC and PHY/POWER".
But you are right, this is not super simple. If you want to do it right.

Alternatively rip out the fan and see if it is just a crappy model – then replace with some Noctua or whatever silent fan is the rage at the moment.