when you hear the noise, just stick your hand in there and stop the fans one by one with your hand. finding the one making the noise should be quick.

---

Are there any tricks that can help me to pinpoint which fan is the culprit here?

Fan problems are highly recurrent in 24/7 working hosts.
It usually happens that you stop one of them for a while, and when turning it on again that typical rattling noise starts to sound...
I published my own tricks at earlier Message #56323, including a descriptive video.

My old Corsair AX1200s have been running continuously for 7 years, two more than their warranty. Some have failed for obvious reasons and been scrapped. I'm replacing dead PSUs with Seasonic TX-850s or TX-1000s. They have a 12-year warranty so they must be confident it lasts.
Has anyone tried the PassMark Inline PSU Tester?
https://www.passmark.com/products/inline-psu-tester/index.php
$590 seems exorbitant. I set an eBay search hoping to get a used one cheap but none have been listed.
I have a Thermaltake Dr Power II meter but I've yet to see a PSU fail its test even when I was convinced that the PSU was the problem.
I think it was Keith that suggested using IPMI to watch the voltages on a running computer to see if PSU is failing. Is this it?
https://github.com/ipmitool/ipmitool
If anyone knows of a good tutorial to learn how to do that it would be greatly appreciated. Swapping parts between a good computer and an ailing computer is time-consuming and not always definitive.

Interesting questions.
In previous Message #53401 I published something about an off-line PSU tester that I've tried.
But as you say, its major ability is to confirm obvious problems...
To put in evidence more subtle PSU problems, an in-line PSU tester would be a very useful tool.
Any experiences regarding this will be welcome.

I think you need a good oscilloscope and a set of artificial variable loads to test a PSU. When a PSU is about to fail (making the PC unreliable), its DC output voltages are probably still within the specification under constant load (a running PC is not a constant load, even when it's idle). The unreliability is caused by the larger spikes (transients) on the DC voltage when a load (for example a GPU) is turned on or off. Such a test equipment (and the expertise to conduct the test) is way more expensive than the extra cost of a reliable PSU, however if you have an oscilloscope, you can test a live system (very carefully, as in the worst case you can break the components which is way more expensive than the PSU).
The unreliability of the PSU usually comes from the aging of the elecrtolytic (or similar) capacitors in it, as their capacity degrades very quickly when the eletcrolyte leaks or evaporates (or both) from them, making the switching elements switch more frequently, which is raising the temperature inside the PSU, which makes the elecrolyte evaporate even faster. The leaking elecrolyte usually leaves visible signs, so a technician can see which capacitor has to be replaced by new ones once the PSU is opened up (but it's a dangerous process, as there are high voltages inside the PSU even days after it's been unpugged from the wall outlet).
There are many DC-DC converters (it's similar to the PSU) on almost every component of a PC (on the motherboard for the CPU and the memory and the chipset, on the GPU, in the SSD drive etc.), as modern chips need very low voltages (around 1V) and high current. For achieving the highest possible efficiency these voltages are converted from the 12V rail (even the PSU itself supplies the 5V and the 3.3V through DC-DC converters from its own inside 12V rail). The electrolythic capactors of these DC-DC converters (if they need such) age the same way as those inside a PSU, but they are much harder to replace (as the motherboards are designed to spread the heat very well, so it's impossible to desolder a single component from them without special equipment). So an aging motherboard can tolerate lower spikes (and ripple) than the same mb when it was brand new.
A general advice for selecting PSUs for crunching:
The PSU should have at least 5 years warranty (the more the merrier).
The PSU should have at least 80+ Gold certification.
The maximum output power rating of the PSU should be 180-200% of the constant load of the cruncher PC.

double post...

I think it was Keith that suggested using IPMI to watch the voltages on a running computer to see if PSU is failing. Is this it?
https://github.com/ipmitool/ipmitool
If anyone knows of a good tutorial to learn how to do that it would be greatly appreciated. Swapping parts between a good computer and an ailing computer is time-consuming and not always definitive.

ipmitool is useless without... IPMI. this is hardware built into the motherboard, if you have it. unless you have a server board, you probably don't have it. just downloading some tool wont give you IPMI. (akin to wanting to "download more RAM").

Supermicro boards have IPMI on most models, So do Asrock Rack, Tyan, Dell/HPE, and many other server manufacturers. usually if you have IPMI you'll have a dedicated LAN port specifically for that function. so you can remote into the system without it even being functional or even powered on. it's very handy. I use it to remotely power cycle a stuck system, remotely push BIOS updates, even VGA redirection.

but like I said, the system needs to have the necessary hardware built into it in the first place. there are some raspberry pi based solutions that provide similar functionality for normal consumer hardware, at least for IPKVM and remote power cycling. not sure about the other stuff.

---

The maximum output power rating of the PSU should be 180-200% of the constant load of the cruncher PC.

An easier way to understand that is to say that the maximum efficiency of the PSU is at half its power rating. A computer will run best near that power. See the efficiency graph under Overview: https://seasonic.com/prime-tx#specification

I find it useful to put a label on each PSU with the date I placed it in service.

The unreliability of the PSU usually comes from the aging of the elecrtolytic (or similar) capacitors in it, as their capacity degrades very quickly when the eletcrolyte leaks or evaporates (or both) from them, making the switching elements switch more frequently, which is raising the temperature inside the PSU, which makes the elecrolyte evaporate even faster.

I find it odd how many computer trays or cases align the PSU screw holes to have the PSU fan suck in the hot air from the computer. I use open trays and always point my PSU fan away from the motherboard.

I find it odd how many computer trays or cases align the PSU screw holes to have the PSU fan suck in the hot air from the computer. I use open trays and always point my PSU fan away from the motherboard.

That odd PSU orientation is inherited from the era when the only active cooled component in a PC was the PSU. Back then the PSUs had about 60-70% efficiency, which was quite good compared to regulated linear PSUs. (not used in IBM PCs as far as I remember, but used in home computers like Sinclair ZX series and the comparable Commodore series.)

Some of the latest "prosumer" motherboards are including IPMI interfaces. But usually cheaper knockoff versions of the interface normally found on real server motherboards.

Just as a reminder:

Remember that a periodic maintenance is worth for your hosts health.
In doubt?
I'm showing true images of a "poorly maintained host".
This system was experiencing excessive overall hardware temperatures, and sporadic hang ups.
Please, if you're weak-hearted, don't click over below link...



After a thorough cleaning and CPU thermal paste replacement, problems were solved.

The hardware enthusiast's corner

The first Post of this thread was published on 2 Nov 2019 | 21:44:13 UTC
For me, many hours of fun are involved, and a certain proud for sharing my wanderings.
Always in the aim that they can be useful to those who eventually would need it.
And I've also learned from You many invaluable knowledge that I'm grateful for.

Being such old, at the very end of this thread can be currently read the following label:

Only the first post and the last 75 posts (of the 312 posts in this thread) are displayed.
Click here to also display the remaining posts.

It is customary at other project's forums for when threads become to long or unwieldy to close the original thread and create its successor thread with an enumeration typically.

The hardware enthusiast's corner(2)

It is customary at other project's forums for when threads become to long or unwieldy to close the original thread and create its successor thread with an enumeration typically.

I'm taking this Keith Myers wise advice, and this will be my last post at the original The hardware enthusiast's corner thread.
For better readability, future posts (if any) will be published at a The hardware enthusiast's corner (2) new thread.

Thank you all again for sharing experiences and giving this thread a 10K+ audience!
And special thanks to Gpugrid for harboring it.

ServicEnginIC