EXPIRED Mellanox InfiniBand SX6018 - Switch - EMC only - $300 OBO

ThinkPadMan

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Dec 15, 2020
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I found that 4-pin 1.25mm JST SH5 pigtails fit fine.

I'm trying to match up the pinouts. I have stock fans with same color scheme as kaz Red, White, Blue, Black. Trying to figure out which wire is which. I have Noctua PWM fans with the Black, Yellow, Green, Blue leads.
 

gb00s

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Jul 25, 2018
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Malta
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I'm trying to match up the pinouts. I have stock fans with same color scheme as kaz Red, White, Blue, Black. Trying to figure out which wire is which. I have Noctua PWM fans with the Black, Yellow, Green, Blue leads.
The Noctua PWM layout is exactly the same as @necr described. I installed a 14' Noctua PWM for testing this way. If I'm not mistaken all PWM Noctuas have the same pinout layout.
 

ThinkPadMan

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Dec 15, 2020
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@gb00s Thanks. Yea the Noctura side I think I have figured out:

Order from right to left if looking at the plug
Black - Ground
Yellow - +12V
Green - RPM
Blue - PWM

Which as you said matches @necr

It's trying to then match up the noctura to the pins on the board of the SX6036 I'm having trouble with, as I have stock ADDA fans, the fan wires coming off the stock fan plug are like the stock fan picture in Kaz's post.

Red
White
Blue
Black

I pulled up engineering schematics on a similar ADDA fan from their website late last night. Its showing the following in terms of colors of the wires not necessarily in a pinout order, but I think I can piece it together, I'll have to look at it again later tonight when off work :

Red = positive ; Black = negative. White = FG ; Blue = PWM
 
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ThinkPadMan

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Dec 15, 2020
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Posting back, I used Noctua PWM fans, NF-A4x20. It's blowing air, switch status light went green after bootup. No longer hear the jet engine full throttle and back down reving up and down cycling sound. PSU still needs to be done, that's the loud noise maker at the moment.
 

Mighty Man

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Aug 9, 2019
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Posting back, I used Noctua PWM fans, NF-A4x20. It's blowing air, switch status light went green after bootup. No longer hear the jet engine full throttle and back down reving up and down cycling sound. PSU still needs to be done, that's the loud noise maker at the moment.
Could you post some pics? Preferably with the color coded connectors?
Thanks for some great research!
MM
 

ThinkPadMan

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Dec 15, 2020
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I have taken it apart again. Overall it did work, but the amount of wiring with all the splicing took up lots of room and blocked airflow. Also I did start to hear the oscillations that were referenced earlier on the PWM comment. Re-opening everything back up, will take photos and probably cutting the PWM leads off so they run 100% speed.
 

fatmandandan

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Apr 22, 2021
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I just switched over both the chassis and PSU fans on my SX-6036 and oddly enough, the chassis fans are showing failed at 5K rpm while the PSU fan reads as ok. I was wondering if anyone else had this problem/knows of a solution

Edit: switched over from Stock AD0412UB-B5BDS (Chassis) and PMD1204PQBX-A (PSU) to Noctua NF-A4x20-FLX on both
 
Last edited:

fatmandandan

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Apr 22, 2021
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switched over from what to what?

Sorry, totally forgot to mention it: Switched over from Stock AD0412UB-B5BDS (Chassis) and PMD1204PQBX-A (PSU) to Noctua NF-A4x20-FLX on both. Since they're 3 pin fans, I left the PWM wire unplugged. The RPM Reads correctly, but shows as failed in the cli. Weirdly though, it shows as OK in the webui.

Thanks!
1619419653272.png1619419708541.png
 

Rand__

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Mar 6, 2014
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Ah can't help with that, never modded the fans, sorry; hopefully somebody else can chime in.
 

ThinkPadMan

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Dec 15, 2020
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I went with the 4 pin Noctua's. First attempt everything worked fine. Then after reboot, I noticed the oscillating sound that a previous poster described, it was very quiet but it was a very subtle annoyance, they would hum slightly louder and slightly lower, and the frequency of the oscillation would speed up between louder and lower. I don't know how to best describe it, but it would rev up and then rev down, similar to like a car's engine climbing and descending hills. It still overall was very quiet compared to the normal jet engine sounds, but just seem annoying, and would catch my attention.

So... I clipped I think the PWM wires. When it boots up, all lights are green, then eventually the lights turn red. I think its a very similar issue to yours, PSU reads ok, but the 4 fans spit off the error. In the WebGui it reports fans are fine temps are fine. I can't recall if the error was bad RPMs or not. The only thought I had was maybe faking it out by running the pwm wires to ground or something, like take all 4 clipped wires and just push them to one gound wire. I left it on for like an overnight and temps read ok. Overall after taking it apart 2 times, I just said forget it, it works, it's not overheating, so it shows red a red light, it still works OK, everything connects and links up, what's the big deal let the system complain, its not like the part is actually failing which I kind of think thats what the alarms are there for...to alert you to a stock part failure, not my crazy modding. My other thought was if it got so bad, I'd pick up a spare fan assembly and PSU, and just hot swap em out back to factory if I ever put it under heavy load. I hoped everything would light up green and stay green, but I'm not going to let a red light ruffle my feathers when the thing keeps on working fine.
 

ThinkPadMan

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Dec 15, 2020
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PS - Just to clarify. I never actually tried routing the 4 clipped PWM wires to a ground, that was my next thought of what I may be able to do to solve the red light/alarm problem. I gave up / said forget it I can live with the red light, before even attempting that, once realizing all was well with temps after leaving it on overnight.
 

fatmandandan

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Apr 22, 2021
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PS - Just to clarify. I never actually tried routing the 4 clipped PWM wires to a ground, that was my next thought of what I may be able to do to solve the red light/alarm problem. I gave up / said forget it I can live with the red light, before even attempting that, once realizing all was well with temps after leaving it on overnight.

Thanks for the reply! Yeah, haha I just like seeing the green light. I ended up just soldering in a single 555 timer circuit chained to each of the Tach wires on the fans. I'll probably end up looking for a software solution, because the timer circuit removes information about fan failure. I'll definitely update if I find anything.

Will absolutely pick up a spare fan assembly and PSU, but temps look great so far. I'm only planning to have a maximum of 5 machines on the network, so I think temps should still stay in check after I get everything hooked up.

For future reference, on the fans I saw in my switch, the pinout was:

RED --> 12V
Yellow --> Tach
Blue --> PWM
Black --> GND
 

ThinkPadMan

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Dec 15, 2020
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Yea, I used to always like things to be just right, like had the mentality of I need to get these lights green, and had it for this mod. But then I had to check my mentality. I realized I would be spending so much time fusing with these fans, rather than accomplishing what I wanted to do with the actual switch and using the switch. I said to myself, hey its quiet now, mission accomplished, lets get the links up and running.

After I got the links up, I had up to 6 machines connected, so that's 12 cables, and the status lights on the uplink were on, wasn't really pushing data through em, but if after being on for a few days nothing went down, figured its gotta be ok. The temps in the software were within range / not much higher than with the regular fans in there. And mind you just by putting my hand up to the switch, the air blowing through felt relatively cool, it was not hot by any means. I had read all sorts of arguments comparing the CFM on different fans etc blah blah vs the noctuas being so low on CFM. I just took the mentality, hey it works, the system is just throwing off an alarm because yea I actually messed with it and it's not within design spec, if temps are good, I'm not frying anything. Mind you I probably spent about the same amount of money on the darn fans then I did on the switch itself. I didn't go out and buy spare stock fan assembly / psu just yet, because I was like I've spent enough dough on this as is for the time being. Figured wait a couple paychecks down the road before spending anything more on it.
 

kalleersej25

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Mar 17, 2021
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I've got one of those cheap unmanaged MSX6790 for my homelab.
Almost had no problem with upgrading stock fans with noctua's 40x20mm ones. But I can't solve the puzzle with PSU fan which produces 60dBA at 23000 RPM. I've tried to solder in fan emulator, tuned to original RPM, but it didn't do. Looks like PSU checks several points of fan RPM.
Just got this switch myself, how are the temps after replacing all the fans?
 

Blubster

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Feb 25, 2014
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Hey guys, i just finished replaced the 6 fans of my SX6018 with Noctua NF-A4x20-FLX.
IMG_20210730_154008 (Grand).jpg
(sorry about the mess... :rolleyes:)
IMG_20210730_155650 (Grand).jpg
IMG_20210730_160349 (Grand).jpg



sx6018_noctua1.jpg
sx6018_noctua2.png
sx6018_noctua3.png
It is not very much loaded, all is green so far. It is so much quieter...

Temps of course did rise a bit :
sx6018_noctua4.png

I'm never going to load the switch with a lot of activity or with all ports, so i believe the rise of temperature is well acceptable given the lower noise.
At least the green light is still on so if there is some issue i will be able to see it.
For me, the pinout was exactly the same between the Noctua fans and the stock ones. I had Delta FFB0412SHN.
Something that may be important for others, i had to redrill the fan mounting holes as they were too small. I used a 4mm drill bit.
Thanks for everyone who shared their experience with the fan replacement here, it made me do it myself!