Mellanox SX6012 Fan replacements

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amlai

New Member
Aug 25, 2023
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Forgot to report back :)

New fans has been received, installed - and results are in the ballpark of what I expected.

If I run the fans without any modications I shave off a couple of watts (hard to measure 100%) - and noise levels are a little lower than the original fans (when having applied the fae mlxi2c set_fan /MGMT/FAN1 1 25)
Out of curiosity, what did you do in order to connect the fans? I purchased a set of fans, but they need a connector to attach to the leads/wires. Did you desolder the old fan pins?
 

Bjorn Smith

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Sep 3, 2019
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r00t.dk
Out of curiosity, what did you do in order to connect the fans? I purchased a set of fans, but they need a connector to attach to the leads/wires. Did you desolder the old fan pins?
I bought crimp terminals and housing and connected the wires.


And


That works - and then you just need a set of pliers.

Its a PITA to work with - but with a magnifying glass it is possible :)

Or you can buy the correct crimp plier and its most likely easy as a breeze :)
 
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amlai

New Member
Aug 25, 2023
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Thank you! This is perfect. I figured it was a standard part but couldn't figure out what it was. I ordered some parts from Digi-Key and if they're the right ones, I will let everyone know what to buy from that catalog.
 

Bjorn Smith

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Sep 3, 2019
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Thank you! This is perfect. I figured it was a standard part but couldn't figure out what it was. I ordered some parts from Digi-Key and if they're the right ones, I will let everyone know what to buy from that catalog.
You are welcome :) Took me a while to figure out the correct ones - but I also got some help from here :)
 

unphased

Active Member
Jun 9, 2022
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Any update here on firmware mod to break the 4000 RPM lower fan limit?

My SX6036 switch I just got comes fitted with Delta FFB0412SHN's -- "Super High Noise" ;)

I did find scrolling around Delta's product picker that the VHN I'll call that "Very High Noise" fans are basically half the airflow (and so likely still sufficient) so it is great to know that this is one way forward.

I also in some light searching found this as an alternative: Amazon.com

The 9500RPM 13mmH2O Delta VHN fan is at much more of a sweet spot though, since this 6000RPM Arctic fan can only achieve 4.2mmH2O. However it is about the same proportion cheaper!

Noctua NF-A4x20 could fit, but is 2.26mmH2O and not in the right ballpark sadly.

If I make a project out of this I would definitely want to use larger fans, but only having 40mm to work with is definitely troublesome. Having to fake the RPM signal is also troublesome, though I seem to recall somebody had a 555 timer solution for that or something.

Let us also not forget, that in both of the redundant power supplies there is also another identical 0412SHN fan, so if we want to reduce noise we have to replace all of these fans, total of 6 in my SX6036.
 
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unphased

Active Member
Jun 9, 2022
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Good call thanks for sharing those links. Given the ubiquity of 0.1 inch pitch pins and connectors I am certainly liable to cobble together something last minute that will work, but without the proper plastic retention mechanisms. That's not even gonna be good enough for government work, homelabbing is a different animal though. I don't use string and bubble gum, but I do use kapton tape.
 

unphased

Active Member
Jun 9, 2022
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@amlai I am not sure since you never stated the exact hardware you are dealing with the fan headers for, but on my SX6036 I do not have 0.1 inch pitch connectors. At least with one of these power supplies here, it uses a (tiny by comparison) 0.05 inch pitch connector.

I’m almost certainly going to snip and solder up the wires to swap out the connectors.
 

unphased

Active Member
Jun 9, 2022
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I did this on the SX6012. It may be different on the SX6036.
Yeah they seem to have different fan headers!

That said I did buy and took shipment of some Sunon 2.8W 40x28mm fans that have this type of 0.1inch pitch headers... they may also already be in the right pinout (red and black at opposite ends).

Here it is: https://www.aliexpress.us/item/3256...il_item.4.5298f19cqzjg4m&gatewayAdapt=glo2usa

But this one https://www.aliexpress.us/item/3256805782656918.html?ug_edm_item_id=3256805782656918&pdp_npi=3@dis!USD!$4.89!$4.45!!!!!@2141229716985343943122794d0e90!12000035099567821!edm!!&edm_click_module=item_detail&tracelog=rowan&rowan_id1=aeug_edm_56672_1_en_US_2023-10-28&rowan_msg_id=8169biz_search_product:0:0_574450780$19a7783f2f8249b09b5df00e2a629893&ck=in_edm_other&gatewayAdapt=glo2usa

May be even more of a fit though it seems to have the wrong pinout (standard 4 pin header style but the header is not the desktop fan header type. red and black wires next to each other).
 

Schemer

New Member
Mar 20, 2025
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Yeah they seem to have different fan headers!

That said I did buy and took shipment of some Sunon 2.8W 40x28mm fans that have this type of 0.1inch pitch headers... they may also already be in the right pinout (red and black at opposite ends).

Here it is: https://www.aliexpress.us/item/3256...il_item.4.5298f19cqzjg4m&gatewayAdapt=glo2usa

But this one https://www.aliexpress.us/item/3256805782656918.html?ug_edm_item_id=3256805782656918&pdp_npi=3@dis!USD!$4.89!$4.45!!!!!@2141229716985343943122794d0e90!12000035099567821!edm!!&edm_click_module=item_detail&tracelog=rowan&rowan_id1=aeug_edm_56672_1_en_US_2023-10-28&rowan_msg_id=8169biz_search_product:0:0_574450780$19a7783f2f8249b09b5df00e2a629893&ck=in_edm_other&gatewayAdapt=glo2usa

May be even more of a fit though it seems to have the wrong pinout (standard 4 pin header style but the header is not the desktop fan header type. red and black wires next to each other).

Hi!, i've seen a few of your post around the forum, I too have been afflicted with the high pitched noise of the sx6036 fans. I was curious if you came to a definitive conclusion on fan replacements for this. I need to do something soonish, otherwise i'll be running my fans at 20%, which is still too annoying forever.
 

unphased

Active Member
Jun 9, 2022
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Hi!, i've seen a few of your post around the forum, I too have been afflicted with the high pitched noise of the sx6036 fans. I was curious if you came to a definitive conclusion on fan replacements for this. I need to do something soonish, otherwise i'll be running my fans at 20%, which is still too annoying forever.
Thanks, yes i must admit i havent gone even as hard as 20% because i haven't had time to tinker with this thing in months, closer to a year at this point. Yeah I just deal with the noise, it's already a bit down compared to the usual. notably i haven't done a fan swap on the power supply so it's probably generating the majority of the noise for now. I am aware of an "fae" command i should try to gain further control than i have been over the fan speed setting. I was hoping just going to the arctic 6krpm fans was going to be enough to make it quiet enough. like i said i only ordered one set of 4 of these so I need to order more for the PSU's.

Honestly i don't think 40mm fans can ever be quiet enough without risking possible overheat but then again i do not put a lot of load on this thing. That said I think its onboard computer will be the limiting factor in terms of temperature (compared to the ASIC driving the ports which is cooled quite well indeed), i did do a heatsink swap for it with a skived copper heatsink, it's much beefier but i only saw a mild drop in temps on that CPU. I do suppose if anyones going to have a non overheating slowed down 40mm fan SX6036 it'd be mine now, with this heatsink mod on the CPU...

Ideally if you dont mind some fans sticking up in the enclosure i'd say cutting some holes and putting 120mm fans bolted on top sticking out would be the best way to mod this thing. However there is the issue of needing to provide IIRC some ~4k RPM signal to the system so it doesn't constantly beep thinking the fans have failed. You couldn't run any large fans at that RPM without too much noise, and the circuitry being used to warn for fan failure is useful, so i guess what could be ideal is if some circuit existed that we can multiply a 1000rpm fan signal by 5 to to present as a 5000 rpm fan signal is what I'd prescribe.

Still doesn't address how to cool the PSU's. At the end of the day this is not an easy switch to make very quiet.
 

Schemer

New Member
Mar 20, 2025
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Thanks, yes i must admit i havent gone even as hard as 20% because i haven't had time to tinker with this thing in months, closer to a year at this point. Yeah I just deal with the noise, it's already a bit down compared to the usual. notably i haven't done a fan swap on the power supply so it's probably generating the majority of the noise for now. I am aware of an "fae" command i should try to gain further control than i have been over the fan speed setting. I was hoping just going to the arctic 6krpm fans was going to be enough to make it quiet enough. like i said i only ordered one set of 4 of these so I need to order more for the PSU's.

Honestly i don't think 40mm fans can ever be quiet enough without risking possible overheat but then again i do not put a lot of load on this thing. That said I think its onboard computer will be the limiting factor in terms of temperature (compared to the ASIC driving the ports which is cooled quite well indeed), i did do a heatsink swap for it with a skived copper heatsink, it's much beefier but i only saw a mild drop in temps on that CPU. I do suppose if anyones going to have a non overheating slowed down 40mm fan SX6036 it'd be mine now, with this heatsink mod on the CPU...

Ideally if you dont mind some fans sticking up in the enclosure i'd say cutting some holes and putting 120mm fans bolted on top sticking out would be the best way to mod this thing. However there is the issue of needing to provide IIRC some ~4k RPM signal to the system so it doesn't constantly beep thinking the fans have failed. You couldn't run any large fans at that RPM without too much noise, and the circuitry being used to warn for fan failure is useful, so i guess what could be ideal is if some circuit existed that we can multiply a 1000rpm fan signal by 5 to to present as a 5000 rpm fan signal is what I'd prescribe.

Still doesn't address how to cool the PSU's. At the end of the day this is not an easy switch to make very quiet.
Yea, that definitely seems to be the case, not easy indeed. I've heard of someone with noctua nf a4x20 swapped into theirs, but they said that their "contact" did the mod whatever that means. They didn't give very much information
 

unphased

Active Member
Jun 9, 2022
170
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As far as i understand it the fan control is difficult without further much harder hackery to adjust the low limit of alarming at around 4k RPM, and I don't believe 40mm fans at 4krpm are very quiet. Not these 28mm thick guys at any rate. 10mm thick 40mm noctua fans at 4k rpm are an acceptable noise level, but they don't make any sense to try to install in a thing such as this with how much they cost.

I am not sure if the switch refuses to run properly if you just diable the speaker, i guess hacking a timer circuit to feed it a signal it likes is the way to go to avoid worrying about that, but it's lame since that won't even alert you anymore if your fans DO die in there.
 

Schemer

New Member
Mar 20, 2025
6
0
1
As far as i understand it the fan control is difficult without further much harder hackery to adjust the low limit of alarming at around 4k RPM, and I don't believe 40mm fans at 4krpm are very quiet. Not these 28mm thick guys at any rate. 10mm thick 40mm noctua fans at 4k rpm are an acceptable noise level, but they don't make any sense to try to install in a thing such as this with how much they cost.

I am not sure if the switch refuses to run properly if you just diable the speaker, i guess hacking a timer circuit to feed it a signal it likes is the way to go to avoid worrying about that, but it's lame since that won't even alert you anymore if your fans DO die in there.
Well I'm not super knowledgeable on this, but I spent a few days digging through the firmware and the file system as well as spent a few hours with a friend... and I really can't find any where I can set the lower limit, I even forced the switch to coredump a few times which should dump the register values with no luck. This one is a little tough hahaha.