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

[@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.

[@The-Weekend-Warrior]

I know it's too late for you as the comment I'm replying to is 2y old, but that's probably not a PWM fan. Be sure to check if you need the PWM or FLX type, they're not the same. Maybe useful info for somebody else landing here...

[@tobyweston-author9034]

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!

[@razvangrigore322]

If you connect the blue wire to the ground, the fan stops (because it's the PWM RPM control wire). Are you sure this is the right way? I'm also interested in fixing the error/alert.

[@tobyweston-author9034]

@@razvangrigore322 yes, this worked for me. I have read that there are two different types of fan in the routers. I think on my model the blue is not rpm, but error, i.e. it has a signal when the fan is stopped.

[@KevinCrabb]

​@@tobyweston-author9034 For the 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.

[@tobyweston-author9034]

@@KevinCrabb for me, blue went to ground, until then it worked but with blinking error light.

[@harl00]

further to this - appears that you need to use the second socket - closest to where the fans are, rather than the furthest to quelch the fan alert.

[@britanniasecurityservices982]

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!

[@DcSoundOp]

Glad it helped, good luck with your 350P, the wiring can be different from one model to another, so double check everything.

[@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.

[@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!

[@DcSoundOp]

Thanks for checking out the video and for the great tips! I apprecite your help!

[@martinsholev7811]

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.

[@DcSoundOp]

Hey Buri, I probably should have done more testing with temp measurements, but honestly this one hardly gets warm to the touch & I don't have enough PoE devices here to really get it warmed up by using them all at once. I did get a fan warning light in software at first, but I think that was because I powered it up with only one fan in it during the swap. After clearing that alert, it has been on 24/7 under my desk and is still just slightly warm with no issues. Again, I'm not stressing this one at all though.

[@BuriTechVids]

@@DcSoundOp That's good to hear. I'm planning to buy SG350X-24P (24 port, with PoE 195W & 4x 10 Gbps ports) for live stream purposes (NDI & Dante) But it can't be so loud. I have some Noctua fans already in the portable rack and this noise is absolutely fine for me. :) Btw. Are you sure that blue wire is PWM? Because every article I read said, that this is tach wire (measuring RPM). So I'm a bit confused even I know that in PC world blue wire is PWM (but this can be not true in Cisco-customized pins). But when it is PWM wire, how Cisco knows about fan failure? It hasnt yellow (signal pulse signal). But then if it's signal pulse signal, it means that PWM doesn't work and it uses VCM (voltage control mode) to regulate speed. And my theory is, that yours fans are running on full speed and you have no fan health errors because your "PWM" wire is grounded. Am I wrong? :)

[@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.

[@Andy-kr9iq]

Noctua's own specs are consistent with this (google noctua fan wire color and first link is to their own site). Green is RPM, and blue is PWM on the fans. What kind of damage are we talking about here if shorting block detection in order to make them work? Risk of overheating when fan failure is not detected?

[@GGLinnk]

@@Andy-kr9iq Precisely, and more. Shorting will make the system think fans are ok. Multiple scenarios: 1. Fans are not ok AT ALL. PSU will overheat and can cause multiple damages. Burns, fire, overpower, unstable power, that could even propagate to the POE. This not only concerns PSU but mainboard too. 2. Without an appropriate resistor, can destroy/damage the Cisco fan IC making them go unstable. That may cause damages to the fan. That may flow back to other components. Basically you can imagine pretty much any scenarios based on these parameters. Sorry for this unelaborated comment I'm tired XD

[@hiasiboy90]

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

[@kasperandersen7457]

I have followed your Guide and done the same on my SG200. but in Cisco GUI under - Health it sometimes writes Fan Status: Fail and some time Fan Status: OK But thanks for the tip :)

[@DcSoundOp]

Hey Kasper, as John D pointed out in another comment here, grounding each of the blue pins should stop the alert & indicator if you're seeing them pop up.

[@data-net]

Hey @DcSoundOp, when I ground each of the blue pins, the fans stop! There's probably something wrong. @KevinCrabb sad yellow to red, black to black, blue to blue, and Green to ground. Hmm?

[@jasonanderson1341]

If I’m not mistaken the red wire on this fan is 12 volts. So when you connect the red from the Noctua to the yellow on the original fan clip, you’re sending 12volts back to a 3volt wire on the fan.

[@DcSoundOp]

I don't know what you are trying to say with 'sending 12 volts back to a 3 volt wire'? Also, there was no Yellow on the original fan clip...

[@coleacomb]

This does NOT work on the SG-200 50P. Supplied voltage is below the operating range of the noctua fans which is why it only spins for a second then dies. After it spins, then stops, you can hear a clicking in the fan. Not sure how this differs from the SG300 but unfortunately this guide doesn't translate between the two

[@ki113r0f5h4d0w5]

Did the changing of the fans affect the Power over Ethernet functionality of the switch?

[@daibonehead]

I changed mine yesterday. POE was disabled and I thought it was related to the blue or green grounding snafu (which I need to resolve just yet). However, going into the gui I was able to change the POE settings manually and swithc it on for the two ports that need it. Now my wireless access points are being powered by POE.

[@-wilson-]

I tested 20V FLX 3wire, must be change wire order,but it only working a few seconds, if use it directly not change wire order it doesn't work at all

[@GT-168]

I have a SG350-28p. Has anyone use this switch with same procedure shown in the video to swap out the fans? From reading all the comments, it looks like the PWM fan shown in the video is the right fan to get and the only update would to ground the blue wire instead of splicing it. Is this correct? Will the fun generate enough pressure when switch is running with heavy load? Thanks in advance!

[@klemenbrezavscek326]

Did you get any info regarding that?

[@SomeTechGuy666]

The SG200-18, 18P and 28 are all fanless.

[@DcSoundOp]

They don't make a 28 port in the SG-200 range, only the 26 and it most definitely does have a fan.

[@johnd2970]

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!

[@michaelkaeckert2983]

Hello, a quick question. What did you do exactly? Did you short-circuit the blue cable with the black cable?

[@tobyweston-author9034]

EDIT : SOLVED I am a bit of a noob when it comes to this type of thing... which of the fans did you buy? PVM or FLX? Also, how did you ground the blue pins? Did you solder them or is there a convenient jumper I can use? Many thanks

[@tobyweston-author9034]

If anybody is interested, I got this to work. See comment in the main thread.

[@walxer77]

@@tobyweston-author9034 I have a SG-300 28P POE I put Noctua fans as described in video and I got same issue blinking System LED. You mean that instead of blue (from original cable) to green (of Noctua fan), I have to cut this connection and put blue touching earth somewhere in case? Where do you suggest ? This will put all 3 OK in Status -> Health menu??

[@tobyweston-author9034]

yes. I attached to a screw on the case. long time ago, forget which one.@@walxer77

[@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

[@tinkerscustom9568]

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?

[@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.

[@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.

[@wellingtonfreirerosa]

but it has a much lower CFM too, monitor the temperature, as you may have a cooling deficiency. A normal fan has an average of 15CFM, the Noctua has 5.5CFM

[@razvangrigore322]

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...

[@DcSoundOp]

Razvan... thanks for the message. I just ordered one of the models you suggested to compare it with what I put in this one to see what the deal is. If I got it wrong, I'll do another update video to clear things up. I'll add the 3-wire link to the description now. Thanks again.

[@razvangrigore322]

just got my 4 wire PWM ones from Amazon and not sure what the 4th wire does 🙂 the FLX description does not mention anything about PWM... only fixed rotation on 3 levels: "5000/4400/3700rpm speed settings via Low-Noise Adaptors" confusing indeed...

[@nolancraw]

Thanks for making this video! Do you know if this will work on the SG 500-28P?

[@aeroturner]

Has anyone done this and can comment how the temps were after the change? I know these have about 1/4 the airflow of the stock fans, does this cause temps to sometimes get to problematic levels?

[@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.

[@DcSoundOp]

Thanks for the tip!

[@hav8593]

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

[@DcSoundOp]

Thanks, will do!

[@cashout8582]

My Cisco ethernet switch uses 40 x 15 mm fans but there is no space for a 40x20 fan. Could I replace the 40x15 with a 40x10?

[@DcSoundOp]

It sounds like it should fit, but you need to compare the other specs to see if it is a good replacement.

[@andyonion3408]

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.

[@DcSoundOp]

Thanks for the message Andy!

[@renod42]

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

[@DcSoundOp]

Two of them at FOH is worth a try at making them quieter for sure. Let me know how it works out for you if you give it a go. Thanks for the message Terry!

[@nolancraw]

I used this guide, and these fans on my SG-500-28P, and I get an error that says "%Environment-A-FAN-STAT-CHNG: FAN# 1 status changed - not operational." how do I remedy this ?

[@jonnyawright]

I've got an SG350 and bought a couple of PWM variants. I've tried all sorts of combinations of connecting but the best I've got is a short 1sec spin at power on and then nothing. That's with blue on switch to blue on fan. Green on fan results in no spin at all

[@foxtrot1787]

i cant see which direction you put the noctua fans in?

[@DcSoundOp]

If you're looking at the back panel of the switch, you want to be able to see the Noctua label through the grill, with the fan wiring leading off the bottom right of the fan as you're looking at it.

[@AlanDike]

The sg line doesnt run the same cli as the other cisco switches.. might be of limited utility for learning cisco

[@brucespeidel4132]

What is the model of the Noctua fan for the SG300-28P switch?

[@michaelkaeckert2983]

Servus, hast du nach dem lüftertausch auch einen Fan failure beim Cisco? Und leuchtet dadurch die Status LED Orange? Öfter wird im Netz empfohlen den mittleren PIN mit der Masse kurz zu schließen. Kannst du dazu was sagen? Vielen Dank für deine Hilfe bereits im Voraus...Gruß Michi

[@MiMicTower]

hello, i got a sg350-52p switch and it was noisy as well. i did the same prosejer you did. with the red to yellow, blue to green, and black to black. after installing I thought why not give it a quick turn on. no fans turned what so ever. I did the quick splicers too. someone said I should do the red and black and just cut the green since it would turn off the control , but I don't want to lose anymore splicers. I'm wondering if this is something I have to do in the GUI to re-initulize the fans to start? or through putty? if someone has an answer for this this would be completely apprecated.

[@DcSoundOp]

Hi Arnold, I don't have any experience with the SG350 & based on the comments other folks have left here, it seems like they are absolutely not the same as the model 300 and maybe even differ from one unit to the next.

[@MiMicTower]

​@DcSoundOp out of curiosity is it amperage? The fan from the sg350 is a 12v .24a fan. And the noctuea is a 12v .05a fan. What if you put a resistor? Is this likely the case?

[@walxer77]

@@DcSoundOp Hi I have same model than you, I did all of your steps (you are my hero 😊) but have you found a solution for blinking System LED with annoying fan error?

[@compirri147]

Hi, great vid!! Did you got FAN Errors? Mine shows Led blinking in orange and in the UI alerts some FAN Errors, they still working and spinning. Any clue?? Thanks!

[@DcSoundOp]

Hey, thanks for the question. The comments on this video have been all over the board with folks getting varied results and finding solutions for issues they had that I did not experience. The best I can tell is there were a few different variations (not sure of the order) of these switches, and the fans are not all wired the same in each. If you read through the comments here though, you'll find a few folks who experienced errors and some solutions that worked for them. Sorry for any confusion. Let us know what you find out if you can.

[@ryanpublic]

This didn't work and almost ruined my switch

[@DcSoundOp]

Can you provide more info? What does 'almost ruined' mean? You're only swapping a low voltage fan. The switch also has alarms to warn you of all sorts of faults before things get out of hand. So what happened exactly?