Cisco SG350 series fan replacement?

iotapi322

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Sep 8, 2017
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I have that switch and this post about the suntron fans is WRONG. I had to buy a Noctua NF-A4x20 PWM fan from amazon. I unhooked the other two fans in that platform and it runs just fine.
 

-Mr_Krinkle-

New Member
Apr 21, 2020
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I have that switch and this post about the suntron fans is WRONG. I had to buy a Noctua NF-A4x20 PWM fan from amazon. I unhooked the other two fans in that platform and it runs just fine.
Is that the SG250(-26HP)? Does the adapter kit supplied with the PWM version allow you to connect directly to the fan headers or did you need to re-pin?
 

iotapi322

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Sep 8, 2017
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Is that the SG250(-26HP)? Does the adapter kit supplied with the PWM version allow you to connect directly to the fan headers or did you need to re-pin?
I had to slice off the keyed interface on the plug, so i decided to just use the plug from the existing fan... I believe that I just unplugged all 3 ports and plugged in the new fan to those 3 pins. Mine is th SG350XG-24F it's a 24-Port 10G SFP+ that I found in the trash at work.
 

Kraken17

New Member
Feb 7, 2021
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Hi

I have S350XG-48T and SG300-28MP

I read carefully this thread but It doesn't work for me :(

sunon fan works with random error
Noctua NF A4x20 PWM starts a few seconds and stop ??? with error too

@iotapi322 please can you explain what you've done ?

thanks for your help!
 

jjacobs

Member
Dec 25, 2020
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I'll pile on this thread. I have a SG-220-50P. I replaced the fans with Noctua fans and, as expected, I have a fan fault. I also don't have POE. Any thoughts on how to get POE back? I only want to power two POE devices, less than 30 watts total. I've seen the kits on eBay, but wondering if there is some other way to trick it into turning the POE on. Thanks.
 
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psannz

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Jun 15, 2016
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sunon fan works with random error
Noctua NF A4x20 PWM starts a few seconds and stop ??? with error too
Did you check whether the cables are in the correct order in the 3-pin plug?
If I remember correctly, Cisco went went with a non-standard order. At least they did with the SG300s. Normally a 3-pin fan would go ground-vdc-tacho. With the SG300 fans however they used vdc-tacho-ground.
 

Kraken17

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Feb 7, 2021
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Hi @psannz
thanks for your answer.
Yes I replaced PIN in correct order.

But it is not tacho but PWM signal in the middle. I tested VDC-PWM-ground and VDC-tacho-ground because I tested noctua PWM with 4 wires given by @iotapi322

but it starts and stops after some seconds...
 

iotapi322

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Sep 8, 2017
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I am traveling right now but when I get back I can crack open the switch and take a pic if needed
 

Spony

New Member
Feb 19, 2021
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Hi @psannz
thanks for your answer.
Yes I replaced PIN in correct order.

But it is not tacho but PWM signal in the middle. I tested VDC-PWM-ground and VDC-tacho-ground because I tested noctua PWM with 4 wires given by @iotapi322

but it starts and stops after some seconds...
Hey, I also have the SG350x-48P and want to replace the fan too. Is there a solution now?

Noctua NF A4x20 works in the FLX or PWM version?
Any news?
 

geho10

New Member
Mar 3, 2021
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I had the same Problem with the „Noctua NF-A4x20 FLX“ replacement fan.

Problem 1: the pin layout is different
pin_layout2.jpg
Solution: just switch the pins - leave the yellow one disconnected. (fan warning will appear)

Here a image of the fan connector: SG350x-24P (original)
fan_connector.jpg

1= 12v
2= fan block detection
3= ground
4= ground

Case 1: Pin 1 and 3 connected
i was experiencing the same issue, that the fan spin up and stops after a few seconds.

after measuring with a mutlimeter i discovered something special: only around 6 volt were supplied and the value changes acording to the ambient temperature

Case 2: Pin 1 and 4 connected
measure: constat 12v --> the Fan is constantly on

Warning: all changes will void your warranty and are on own risk
 
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geho10

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Mar 3, 2021
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here are more images of the final installation:

2021-03-06 09_53_43-Window.jpg

v3.jpg
v2.jpg

working very well so far and the temperatures are in a normal range:
sensor.jpg

The only bad thing is the fan alert - but I can live with that.
 

buri

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Mar 28, 2021
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buri.sk
Hey guys, thanks for info. I plan to buy SG350X-24P and as it will be used in live streaming environment, I have to quiet it down.
@geho10 - Do you think that the alert will not disappear when you connect tach wire back?

Btw. we should unify what blue wire is. It is tacho or PWM? I read in another thread that fan is probably controlled by TC654/TC655 controller and the data sheet states (first page Description):
In normal fan operation, pulse trains are present at SENSE1 (Pin 8) and SENSE2 (Pin 7). The TC654/ TC655 use these pulses to calculate the fan revolutions per minute (RPM). The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC654/TC655 to assert a logic low alert signal (FAULT). The default threshold value is 500 RPM. Also, if this condition occurs, F1F (bit 0<0>) or F2F (bit 1<0>) in the Status Register will also be set to a ‘1’.
Source: http://ww1.microchip.com/downloads/en/DeviceDoc/20001734C.pdf
Thread I read: https://forums.servethehome.com/ind...-d-10g-base-t-to-sfp-switch.16319/post-160891

And there is also explanation why fan stops after a few seconds is there also (4.1 Fan Startup):
Often overlooked in fan speed control is the actual start-up control period. When starting a fan from a nonoperating condition (fan speed is zero RPM), the desired PWM duty cycle or average fan voltage can not be applied immediately. Since the fan is at a rest position, the fan’s inertia must be overcome to get it started. The best way to accomplish this is to apply the full rated voltage to the fan for one second. This will ensure that in all operating environments, the fan will start and operate properly
And I assume that Notcua is not able to work with 6V properly.
So, this is nice solution @geho10 :)

// all informations is based only from my internet-investigation. :D I haven't bought it yet, so..

And to explain things: If I'm right, PWM is used to regulate voltage directly on VDC pin. PC-style fan works differently from this. So I hope that here should be used FLX Noctua fan.

EDIT 1: Am I right? Btw. I found that Notctua A4x20 can run even with 5V (but needs at least 6V to start what should be okay because of TC654 startup behaviour)

EDIT 2: To support my theory about FLX models, I find out that for example SG350-28MP switch have fan DELTA ELECTRONICS FFB0412VHN and according to data sheet ( https://www.delta-fan.com/Download/Spec/FFB0412VHN-F00.pdf ) BLUE wire is FG signal. And FG signal as I know means "Frequency generator" - in other words: it's square wave (F00 wave) and signal is generated when FAN rotates one cycle. So blue wire should be tacho-wire or just yellow one in PC-style fans. Right? :)

EDIT 3: This guy has different fan in SG200. Okay now I understood confussion about fans and blue wire. So.. when you've got the switch, you have to check original fan model data sheet to find out what blue wire do. Because I found out that some switches uses R00 (blue wire only as lock signal) or F00 (tacho wire). Both are blue but function depends on model of fans. So... there is no general advice about what fan use with SG series at all. It always depedns on concerete model of switch and fan. Check it out and you'll see. :)
 
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phil9878

Member
Apr 2, 2021
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here are more images of the final installation:

View attachment 17793




The only bad thing is the fan alert - but I can live with that.
Thank you a lot.
Even in a closed room, the default fans noise is unsupportable.
I tested your setup, and in deed, I can pull a 120 or 80 mm FAN at 12V, else, the fan must support 6V with default pins layout. I tested with a multimeter.

I was about to drill the case and stick a 90mm FAN on top of it to silence it.
Now, I am ordering the NF-A4x20 fans since they are rated only 14 db and the temps look great on your setup
 

phil9878

Member
Apr 2, 2021
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Sadly, using the two FLX Noctua fans, both modded at 12v max speed, the temperature reaches maximum and all ports are turne off because of overheating.
This happens while using 2 of the 10G ports !

So it is a no go with 10G as the switch needs the extra air flow provided by the two original high cfm fans

I am going to drill the case and mod it with a 90mm as I cannot stand the noise !

Any other idea before I proceed ?
 

geho10

New Member
Mar 3, 2021
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@buri : i tried everything and any combination to get rid of the warning message, but i didn't managed to do it

@phil9878 : do you have mounted the fans in the correct way? the blow direction should be outwards (like on my pictures)

all 4 10G ports are in use (2xcopper and 2 SFP+), 2 WLAN Accesspoints (Unifi AC-Pro) over POE and around 10 other devices with 1G (without POE)

2021-04-08 08_08_31-192.168.88.3 - PuTTY.png

Did you use the noctua extension cables? if yes keep in mind that there are resistors in it to lower the noise - therefore the airflow is reduced.
 
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phil9878

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Apr 2, 2021
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@geho10
Thank you for the feedback

Below are my mod photos:
- the fans properly blow out of the case during all the operation until it overheats
- I tested and they properly get a 12v current
- I did not use the Noctua extension cables, neither those with a resistor to reduce voltage. I modded my own extension cables
- I removed my 23W PoE device, still same issue

Here is the log:
Code:
2147483136    2021-Apr-07 22:30:21    Alert    %Environment-A-ENV-MONITOR-CHNG: sensor 5 (PHY) temperature 93C, temperature out from the critical threshold, enable all ports    
2147483178    2021-Apr-07 22:28:11    Alert    %Environment-A-ENV-MONITOR-CHNG: sensor 5 (PHY) temperature 102C, temperature reached the critical threshold, All ports will be shut down in 120 seconds    
2147483182    2021-Apr-07 22:27:23    Alert    %Environment-A-ENV-MONITOR-CHNG: sensor 5 (PHY) temperature 100C, temperature reached the warning threshold
The case gets very warm at touch from outside when this happens. The hot is mainly in front of the 10G plugged cables
With original fans, no issues

Do you think I should remove the RPM yellow cable ?20210407_205824.jpg20210407_205733.jpg20210407_210016.jpg
 

geho10

New Member
Mar 3, 2021
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hmm ok, that's quite strange - try to remove the tacho cable (yellow), i had some voltage variations while it was connectd.

If you experiencing still some heat issues - try to installd a third fan which blows inwards. (48P Model has this solution as well)

2021-04-08 10_11_44-Cisco SG350 series fan replacement_ _ ServeTheHome Forums.jpg
 
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