Cisco SG300 Switch Fan Noise Fix - Noctua Fan Upgrade for a Quiet Network 🤫

#204 - Setting up a Dante audio network can be very simple. You may only be plugging in a single device, or you could be connecting up an entire campus. Either way, there are a number of reasons you may need to go beyond un-managed switches in any network. No matter what you’re using the network for, this often comes with some unwanted noise. Thankfully, we can hack our network hardware with help from Noctua to cut down on the annoyance. In this video we're modifying the Cisco SG300 with a set of Noctua 12V fans that have a dramatic affect on the unit's noise pollution.

Let us know if you've swapped out the fans in any of your gear & how it worked out.

[johnd]

Thanks for the work you did putting this together. I also was surprised by the fan noise of an SG300 I bought for an office environment. I replaced the stock fans with the two Noctua fans as you described and now I can barely hear the unit. The only modification I made was to ground each of the blue pins on the board. These are tach inputs to determine whether the stock fans are present and operational. Grounding them silences the alerts in the logs & GUI and also eliminates the indicator light flashing amber. Thanks again!

[KevinCrabb]

For the Cisco SG200 to work you need to connect the yellow to red, black to black, blue to blue, and Green to big ground screw to make it work. Tested it and confirmed.

[tex-ranger]

Thank you for taking the time to post this. My QNAP is now the noisiest device in the room! A little modification to your video. I managed to do it without cutting any wires. It is possible to slide out the little metal contacts from both the Noctua and original fans. One can simply switch over the contacts. The original white plug is labelled "1" for pin 1 (Originally red). The pinout is: 1 = Yellow, 2 = Green and 3 = Black. I folded back the blue wire and tucked it under the sheathing. This way, one can return it to stock and nobody would ever know. However, I wish I had read @John D's comment first.

[magikknite]

This is a great tutorial.
My Cisco Switch is uber quiet now and I even upgraded the fans in my WatchGuard X55e Core with the same fans but they worked straight out of the box, without splicing or soldering.

Many thanks :D

[britanniasecurityservices]

Thankyou for taking the time to make this video. I have the SGE-350P and its driving me crazy with vibration and high frequency noise from the fans. Really appreciate the demo and will absolutely do the same in my switch. Thanks!

[andyonion]

This is first class work - I have several SG300 series switches in my current Dante live network, and the 28P is the first one I've had to retrofit. An excellent and informative video.

[PersonSuit]

I did a fan swap on a Cisco SG250X-24. Stock fan was super loud and I seriously considered returning it since the location of the switch was going to be about 3 feet from me. I decided to try a Noctua fan before return it and was shock that it was virtually silent after I installed the new fan. Highly recommend doing this change for really any switch if its in an area that needs to be quiet or quieter.

[tobyweston-author]

Thanks again for the video and also to the other commenters.
I got this to work AND got rid of the flashing yellow fan light by:
-Buying the two Noctua PVM fans
-Using the included adapter to splice the new fan adapter to the old fan's plug
-The fans were a little wider than the old so I had to jimmy them in next to the circuit board. I even had to bend the case a little with pliers.
-The blue wire from the original fan plug is not used, so I took a bit of extra wire to connect this to the big screw on the case that is ground.

All good! The switch is much quieter. The main noise now comes from the wind passing through the case.

Cheers!

[GGLinnk]

CISCO-Blue is NOT the PWM at all. The NOCTUA-Green is not the PWM either !

CISCO-Blue is a fan failure sensor. It sends a 3.3v signal is there is non spinning.
NOCTUA-Green is RPM tachometer. It's the opposite, it sends signal corresponding to the current fan speed.

Connecting those two together will cause FAN error.

Note that this is valid for the SG300 BUT may be incorrect on other models.

You must test using a multimeter the value between black and any other color, fan plugged and find :
COM on the black pin (or any GND)
The 12v rail : It's usually the red wire (CISCO SIDE). (Value about 12v)
The Sensor rail : It's usually the blue wire. NOTE: Sometime it will be RPM sensor (0-3.3v pulse Or 12v). Sometime failure signal (0: working, 3.3v: failure. Or 12v).
(IF ANY : The last rail should be PWM.)

My SG300 have a brushless EFB0412MD.
I've tested the values unconnected to my cisco :
RED: 12v
BLUE: ~200mV spinning, ~3.3v stopped. While being slowed it was around 400mV.

Connected to the cisco the value stayed at ~10/20 mV any scenario unless stopped where the value jumped to 3.3v.

PLEASE DO NOT DEPENDS ON *MY* MESURES, YOURS COULD BE TOTALLY DIFFERENT.
Note that shorting block detection may cause severe damage to your hardware.

[tinkerscustom]

Is PWM required for this? Would the 3pin fans work with this switch? Also, do you have no error lights with your method? All green?

[hav]

Thanks very much, this is an excellent step by step video and the upgraded fans make such a difference. Keep up the good work.

[martingebauer]

Although this is an old thread, I was glad finding it and the advices given. I exchanged the fans using precisely the one shown in the video. Turning the switch on made the fans spin, both in the right direction.
Everything looks fine.
BUT: The Fab-LED on the front starts flashing and the control desktop reports fan failure. The only difference I see is in Current dissipation. Original fan=0.1A each the new ones 0.05A each.
Could it be that there is current sensing in the switch?
Wahl is the result: The GigaBit copper uplink works flawless. The SFP port in my switch is equipped with an optical interface. This is the one which fails.
I have reverted back to the old fans and everything is fine again ...
Any advice from DcSoundOp?

[renod]

I have exactly this hardware (x2 within 3 meters of my mix FoH position). THe noise was something I never anticipated when purchasing and now regret. This sounds like a good solution. Thanks

[VargaBacsi]

If you have a SG300-52MP that has fans with wires that go (from left to right) Yellow, red, black there is no additional modification. I ended up just plugging the Noctua PWM fan right into the header and everything works - after trying the mod above. No warnings in the Cisco GUI either. Hope this helps someone!

No need to mention my switch is killer quiet now! Just ordered the remaining 3x fans to complete the fan upgrade/repair.

[PJBeee]

Total noise-reduction cost - Zero:

I open the SG300-28P switches and connect the two stock fans in series, tying off the unused leads and ignoring the PWM leads entirely (leaving them as-is). This makes the status LED flash, indicating an error condition, but otherwise no ill effects. And then they run much (MUCH) more quietly. To be sure, these modified switches are not put into use in hot equipment closets, nor are they fully loaded with POE devices, so they don't overheat. Never had any issues there.

Alternatively for less noise (but still more than with both fans in series) you can simply unplug one of the fans. Same flashing-LED error condition will occur.

These switches are available used online, are pretty close to bulletproof, and are usually out of warranty anyway, so no fear of warranty issues. And you still have a fully functional Layer 3 gigabit switch in your hands.

Biggest downside of these is that they take quite a while to boot up, but I usually couple them with an inexpensive Cyberpower or APC UPS. And 1 400VA UPS can power at least 2 of these switches.

Also: good idea to flash them with the latest firmware. Once you're used to the process, it isn't too bad. You may have to apply some interim updates to get them current.

Oh yeah, and running the fans slower might just make the fans last even longer. I have many of these modified switches in service for over 3 years, with no problems. And they were bought used in the first place.

Good Luck!

[martinsholev]

Sometimes its very easy just to rewire the pins, no warranty void, no cutting the wires, no splicing, very easy.

How to rewire the pins? Flat screw driver, push the pin from the top side and pull the wire, do the same for the other pins, after that just push the pin inside the RIGHT hole and that's it.

[BuriTechVids]

I'm surprised that you didn't cover anything about temperatures and comparison.. :/ But nice to see that Cisco has no issue (i mean that switch doesn't decide to not boot up) with Noctua fans at all. Thanks for video. I'm considering to buy SG350X-24P and I neede this exact video about loudness because we can't use anything for live streaming in smaller venues. But I think that I will risk it and try that.

[razvangrigore]

Maybe for disambiguation, it would be good to mention Noctua NF-A4x20 FLX, 3 wire. The one in the video it seems to have 4 wires, but the cisco one is still on 3...

[hiasiboy]

I have a cisco 350 28 port poe. I did the fan replacement and now the green light is blinking... Any advice ?

[feedyourspeakers]

I have an sg300 52 port and internally it looks different (obviously). The space for the fans in the 52 port is much less; basically the NF-A4x20 won't fit because of the thickness. All i had to do though was very slightly bend the case lip where the screws hold the fans in like 2-3 millimeters and you can get the new fans in. the cover still slides on normally with no difficulty. Just be aware that you gotta make that little tweak to fit these fans in the 52 port.