I see they have the exact same frustration with the results of trying to research how to safely work on a PSU as I've had. I know there's plenty of info out there about working on CRTs; are the caps in PSUs really more dangerous than that?
Fixing a loud PSU fan without dying
21–30 of 63 posts
Re: Fixing a loud PSU fan without dying
#22Earlier quoted context omitted.
There's a fair bit of survivorship bias in this. That said, modern power supplies use "bleeder resistors" to discharge the capacitors once powered off.
> 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.
Re: Fixing a loud PSU fan without dying
#23I see they have the exact same frustration with the results of trying to research how to safely work on a PSU as I've had. I know there's plenty of info out there about working on CRTs; are the caps in PSUs really more dangerous than that?
Modern computer power supplies are far less dangerous than CRTs were.
CRTs were dangerous because they used extremely high voltages (often as high as 25 kV), and that voltage was often present on the CRT itself, which acted as a capacitor. The capacitance of the CRT was relatively low, but it still stored enough energy to be very hazardous. There's ways to safely discharge them, but you absolutely need to know what you're doing and work with one hand behind your back.
The voltages in a modern switching power supply are much lower (typically no more than ~1.5x line voltage ≈ 180V), and the capacitors usually have "bleeder" resistors which will discharge them to safe voltages within a few seconds. I'd still give one a few minutes before touching it - and maybe check one or two of the bigger capacitors with a multimeter - but it's still much less dangerous.
Re: Fixing a loud PSU fan without dying
#24Earlier quoted context omitted.
I will put hundreds of dollars in Noctua fans into a second-hand chassis without thinking twice. It's sometimes uneconomical from a cost-ratio perspective, but it is crucial to making datacenter-grade equipment actually useable at home.
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?
Re: Fixing a loud PSU fan without dying
#25I see they have the exact same frustration with the results of trying to research how to safely work on a PSU as I've had. I know there's plenty of info out there about working on CRTs; are the caps in PSUs really more dangerous than that?
Modern computer power supplies are far less dangerous than CRTs were. CRTs were dangerous because they used extremely high voltages (often as high as 25 kV), and that voltage was often present on the CRT itself, which acted as a capacitor. The capacitance of the CRT was relatively low, but it still stored enough energy to be very hazardous. There's ways to safely discharge them, but you absolutely need to know what y…
The main danger with CRT HV is not the HV itself but what the shock will make you do, such as jump and cut your hand on something sharp in the chassis, or even crack the neck of the tube, or fall and hit yourself. There is very little current available, especially if the set has been off, but it's comparable to a very painful static shock. Instead, the "low" voltage B+ supply is far more dangerous when the set is on, as that is basically rectified mains.
Re: Fixing a loud PSU fan without dying
#26Earlier quoted context omitted.
There's a fair bit of survivorship bias in this. That said, modern power supplies use "bleeder resistors" to discharge the capacitors once powered off.
> 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.
As a child, I remember being up in the attic with my grandfather. He touched some wires, swore (which was unusual for him), and said 'that was 220'. I still have a healthy respect for power.
Re: Fixing a loud PSU fan without dying
#27I'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.
I have a personal rule that I only follow instructions when I understand more than 10% of the words in them, so I'm buying a new fan.
That's a good personal rule to copy
Re: Fixing a loud PSU fan without dying
#28An important side note is that Cooler Master’s “10-year Warranty” is garbage: > I looked at Cooler Master’s warranty, and for issues within the first two years you have to deal with the retailer. That would be Amazon in my case. So I looked at Amazon’s information on warranty issues. Their policy is that if it’s more than 30 days since purchase, you have to send it off to a third-party repair center and wait for them…
In Europe, it actually matches the law, it is actually better.
- You have a 14 days retraction period, where you can send back the item and get your money back, defect or not. Amazon gives you 30 days and free return shipping.
- Legal warranty is 2 years and is provided by the seller, not the manufacturer. It is Amazon in this case, but it could be a brick and mortar shop or any other seller, including independent sellers. And they have to solve your problem within 30 days (repair, refund, replacement, ...). How to deal with the manufacturer is their problem. Amazon here is perfectly in line with the law.
- Manufacturer warranty and commercial warranty comes in addition to the legal warranty is whatever is written in the contract.
So here, the manufacturer doesn't need to provide warranty directly to the consumer for the first 2 years as the legal warranty covers it. And I am pretty sure that the 8 extra years offered by Cooler Master are even worse than what Amazon offers. For example, they may require you to pay for return shipping and wait even longer. There may be some fine print there too.
Re: Fixing a loud PSU fan without dying
#29I'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.
Then there are the fans with magnetic bearings. Had a few that started making noise but never figured out from where, given there are no touching parts.
Re: Fixing a loud PSU fan without dying
#30I'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.
Never had much success doing this. At best, it worked for a few days, maybe weeks before buzzing again. I tried a variety of lubricants, stuff that I had on hand (WD-40, 3-in-1, lithium grease...) but not petroleum jelly though.
So unless it is a weird fan I can't find elsewhere, now, I just buy a new one.