Replacing noisy stock fans on a HP 1920-24G-PoE+ Switch (JG925A)

I have recently been researching VLANs for my home network. These will be used to split up my network devices into their own logical network, such as IP Cams, IoT devices and Guest WiFi.

My current PoE switch was unmanaged, I had to replace this with a managed version. I already had a HP ProCurve non-PoE switch, I liked it; so I went hunting for a HP branded PoE switch on eBay.

My main requirements were that it was PoE+ capable, Managed, Rack Mountable and had a web-ui (I found this to more intuitive than console).

I found a used HP 1920-24G-PoE+ (180W) Switch, model ID: JG925A for £90. Not bad.

Once the switch arrived, I plugged it into the mains and turned it on. Wow, the fans were loud. The switch comes with two Delta EFB0142HHD 12v fans, these run at 8000 RPM.

This switch was going to be housed in a rack; in a cupboard accessed from my lounge room, so I had to replace the fans with some quieter versions as the fan noise could be heard even when the cupboard door was closed.

I ordered two Noctua NF-A4x20 PWM fans from Amazon, these were the quietest fans I could find, and I had used Noctuas in other devices with great success.

It didn’t matter these new fans were PWM variants, as I wouldn’t be using the PWM wire.

Note: before opening the case of the switch, be sure you’re comfortable with handling electronics. There are PSU capacitors inside which could give a deadly shock if touched.

I installed these fans by snipping the cable of the original fans and of the new Noctuas. Then used some ‘clip-down’ style connectors from eBay. These connectors are great, they don’t crimp the wires and allow the fans to be removed in more less destructive way.

The fans were wired like this:

  • Original fan cable Red wire > Noctua Yellow wire
  • Original fan cable White and Black wires > Noctua Black wire
  • Blue and Yellow Noctua wires are left unconnected.

The White and Black wires were combined to prevent the switch showing errors regarding failed fans. I’m guessing because these Noctuas have a lower RPM speed than the original stock fans, the switch’s self-diagnostics thinks the fans had failed.

I understand the Noctua fans are not as powerful as the stock varient, but this should not cause as issue for me as I am only using about 4 PoE devices. If you’re using more then you may want to monitor the temperatures.

Overall this was a good modification; the switch is now much quieter.

 

 

 

Comments

Morten
  • May 13th, 2021

Hello

How are things working here a few months after doing the mod?
I am considering doing the same mod as you, and just wanted to know if you’ve run into any problems?
i just switched it on and decided that it’s too noisy, even when the switch is booted and the fans reduce their speed.
I would think the reduced speed is close to the Noctuas, but the motor has a really loud whine to it.

Also, if anyone is curious:
The white and black wire you combined is because the Delta fan has a rotation detect alarm, and the Noctua fans has a tacho signal.

The datasheet is here: https://www.delta-fan.com/Download/Spec/EFB0412HHD-R00.pdf

Ryan
  • May 13th, 2021

Hi Morten,

Thanks for the info.

No, I’ve not had any problems. The new fans have been running in the switch for about 6 months in an area where the temperature is around 24 degrees Celsius.

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