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Fixing a loud PSU fan without dying

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Re: Fixing a loud PSU fan without dying

#41

Post by rpcope1 »

Noctua fans are usually a good choice (though I think their industrial line is better, especially if you can get a deal on the splash proof IP66ish ones). That all said, other than having extremely good lifespans for ostensibly a retail oriented fan, the other thing they tout (the low RPM and quietness) sometimes doesn't work well when you're replacing something much different like a high RPM Delta fan. The Noctuas may not push enough air, especially if there's a controller involved. I've had to build add on fan controllers before where whatever it is won't spin the fans fast enough until they heat up too much, which makes things even more fun. Especially for a PSU it's probably worth looking to see if there's a major difference in airflow (and at what RPMs), as it would suck to have your fixed up PSU cook itself because it's not flowing enough air.

Other less prominent vendors often do make easier drop in fans, that often have very good lifespans that might be easier to adapt than Noctua. Sanyo Denki fans easily will long outlive even Noctua (but don't typically play in the retail space); Delta and Dynatron also usually sell at least decent parts that are much better than whatever random chinesium fans lots of stuff come with. All of the above have much more variety in the profile of fan sizes and configurations and I would probably be looking through their parts catalogs to see if they don't have something that's a better fit (they often do).

The only other interesting thing is that I have picked up is soldering seems like a good idea in cases like this, but at least in bigger setups I've seen solder joints fail because of vibration. Maybe not an issue here, but crimping is usually a much better solution for connecting things that need to have a long life and might be vibrating like something attached to a fan.

Re: Fixing a loud PSU fan without dying

#42

Post by shmerl »

rpcope1 wrote: post #39
shmerl wrote: post #36

Get PSU from original manufacturers instead, someone like Seasonic. Most common brands simply repackage stuff and not really the best quality.

Seasonic makes (made?) really excellent PSUs, but they've been real thin on new inventory over the last year or so. Maybe they're getting out of direct retail? Even a second hand older Seasonic platinum PSU is still hands down better than a lot of the new garbage that's getting turned out.

I noticed some of their models are often out of stock. I really hope they aren't quitting.

Re: Fixing a loud PSU fan without dying

#43

Post by userbinator »

serf wrote: post #19
userbinator wrote: post #16

I've "fixed" countless noisy computer fans over the years with simple lubrication. Peel off the label, remove the bung, pry out the circlip and pull the rotor + blade assembly out, clean off any remaining old grease/oil, and then pack the bushing with petroleum jelly before reinserting the shaft. Reassembly is the reverse of disassembly.

doing this on a fan that used a dry lubricant can burn a wire lead from increased startup torque requirements to get it spinning. it's not bad advice but it's worth noting that petroleum jelly is pretty thick compared to a machinists' oil or dry graphite.

The leverage the motor exerts is huge relative to the shaft, and chances are that when the bearing is chattering audibly, it's already been running dry with much higher friction for a while, and worn enough that you'll need the extra viscosity of a grease to fill the clearance.

Re: Fixing a loud PSU fan without dying

#44

Post by scottlamb »

jojobas wrote: post #22
scottlamb wrote: post #18

Earlier quoted context omitted.

> There's a fair bit of survivorship bias in this. Is there? This kind of statement has the potential to exhibit survivorship bias, but I feel like the opposite—"12-year-old dies replacing a power supply fan"—would make headlines. Definitely haven't seen that. Capacitors should be respected for sure, but people don't routinely die in DIY electronics tasks.

Electrical injuries claim some 1000 lives per year in the states, and 20% of all electrical injuries are sustained by children (lethal and non-lethal). I don't think every electrocuted child makes even local headlines.

Sobering for sure, but I think vanishingly few of those are from residual energy in capacitors in unplugged appliances during disassembly, [1] and certainly far from the "this forum is missing x people just like doubled112 because of tragedies" that I imagine when you say "there's a fair bit of survivorship bias in this".

[1] a quick search mentions things like damaged cords, the classic metal object into the outlet, etc. I installed tamper-resistant outlets everywhere in my house to prevent the latter as part of child-proofing. I think they're mandatory now in new construction. I also may have gone a bit overboard trying to instill caution in my children about this this particular risk; my son tonight asked me if he was okay after his sleeve brushed against the metal part of a USB-C connector while he was plugging in his tablet.

Re: Fixing a loud PSU fan without dying

#45

Post by hobs »

victorhooi wrote: post #40
hobs wrote: post #6

Earlier quoted context omitted.

Hilarious to read this on "hacker news" - replacing a standard fan is too dangerous! This is not styropyro.

I think perhaps you might have not read the entire article? =) The danger isn't so much in the fan, but in that the fan is INSIDE OF A COMPUTER PSU . There are mains AC voltages (220V, or 110V) here, and even if unplugged (which is should be) there are also capacitors in there, which you should definitely be cautious of. I've worked in DC (datacenters) before - and I've seen people accidentally drop screws into power…

I appreciate that most folks talking about power on HN are talking about computers, but I decided to not become an electrician in an earlier life.

Taking standard precautions doesn't mean you suddenly shy away from doing basic maintenance. You can use iso alcohol to clean things even if its flammable, just don't use an open flame at the same time.

Re: Fixing a loud PSU fan without dying

#46

Post by jojobas »

scottlamb wrote: post #44
jojobas wrote: post #22

Earlier quoted context omitted.

Electrical injuries claim some 1000 lives per year in the states, and 20% of all electrical injuries are sustained by children (lethal and non-lethal). I don't think every electrocuted child makes even local headlines.

Sobering for sure, but I think vanishingly few of those are from residual energy in capacitors in unplugged appliances during disassembly, [1] and certainly far from the "this forum is missing x people just like doubled112 because of tragedies" that I imagine when you say "there's a fair bit of survivorship bias in this". [1] a quick search mentions things like damaged cords, the classic metal object into the outlet,…

I rather meant statements like "I did X and I didn't die" are open to survivorship bias, than asserting many must have died from this particular cause. I believe bleeder resistors are written in blood though, I vaguely remember electrocution tales from the times when people were expected to replace vacuum tubes in radios.

Re: Fixing a loud PSU fan without dying

#47

Post by sandreas »

Interesting article and great results.

PSUs are probably the only piece of Hardware, i DO NOT fiddle around with, not even for saving lots of money or time.

PSU Capacitors are no joke, especially in (older) TVs. However, I expected more like an instruction manual why PSUs are dangerous and how to properly discharge capacitors before taking them apart less than how to replace a fan although it's dangerous and getting away with it with a simple hint to not touch the capacitors (no offense).

BTW I would recommend to use electrical tape and shrink tube instead of simple adhesive tape (as it looks in the pictures) to prevent lose cables touching the spinning fan.

Re: Fixing a loud PSU fan without dying

#48

Post by umbra07 »

victorhooi wrote: post #40
hobs wrote: post #6

Earlier quoted context omitted.

Hilarious to read this on "hacker news" - replacing a standard fan is too dangerous! This is not styropyro.

I think perhaps you might have not read the entire article? =) The danger isn't so much in the fan, but in that the fan is INSIDE OF A COMPUTER PSU . There are mains AC voltages (220V, or 110V) here, and even if unplugged (which is should be) there are also capacitors in there, which you should definitely be cautious of. I've worked in DC (datacenters) before - and I've seen people accidentally drop screws into power…

> I've seen people accidentally drop screws into power supplies...and well, electric boom, you can guess the rest.

Are we talking like, bad electrical shock, hospitalization, death, etc?

Re: Fixing a loud PSU fan without dying

#49

Post by aaronmdjones »

ydj wrote: post #24
aaronmdjones wrote: post #11

Earlier quoted context omitted.

I have a 12U 19 inch rack built into my computer desk, and I have a couple of NASes in it (2x HPC-8316SA-55RB1). The 40mm fans in the included CRPS PSUs are loud, whiny, and rattly, all at the same time. I replaced all 4 of them with Noctua NF-A4x20s, wired to run at full speed all the time. They still report their speed so the IPMI management interface doesn't consider the power supply fan to have failed, but the PS…

I’ve also done a noctua fan replacement on my ups. My worry is that they are rated for lower airflow than the original fans they replaced. Have you checked whether it stays cool when running on battery?

It's a permanent double conversion UPS; it's always inverting. You could activate the "high efficiency" bypass mode to directly connect the input to the output in the presence of mains AC input, but this would also pass through disturbances like fluctuations, harmonics, and surges, so I don't have it enabled. This wastes about 80W in my setup but whatever. I'm not worried about the inverter temperature is the point I'm trying to make; but I was considering this when I did it, which is why they're wired to run at full speed all the time.
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