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Fixing a loud PSU fan without dying

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Re: Fixing a loud PSU fan without dying

#11

Post by aaronmdjones »

tcdent wrote: post #5
mkayokay wrote: post #2

A new semi-passive 850-watt fully modular PSU is around EUR 130, the Noctua fan around EUR 30. I guess if you know electronics and how to safely handle the PSU internals, the risk of injury is low, but I personally would not risk it for EUR 100. Also, if the only problem was the noisy fan, I guess selling it used would have returned most of the investment, leaving him with like EUR 50 in added cost. Compared to the p…

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 PSU can no longer control the fan's speed.

The PSUs don't run any hotter and I can't hear them now.

I have a used Eaton PW9130 UPS in the bottom of the rack. The 80mm (exhaust) and 60mm (inverter heatsink) fans were likewise louder than I'd like. I replaced them with Noctuas too, again wired to run at full speed all the time, and the UPS' Web/SNMP card confirms it's still no hotter than 30'C internally. I can't hear that now either.

Hilariously, the most critical fan, the original inverter heatsink fan, is a 2-pin fan, so it probably can't even detect when it has failed (unless it's detecting fan failure by monitoring current consumption). The original rear exhaust fan uses a locked rotor sensor rather than a tachometer, which required a bit of bodging to convince the UPS that it has not failed. Oh well.

Re: Fixing a loud PSU fan without dying

#12

Post by jojobas »

doubled112 wrote: post #8
jojobas wrote: post #4

Earlier quoted context omitted.

C grade high school physics understanding makes the risk exactly zero. Selling defective stuff without declaring is bad mojo, with declaring it just delegates the pain in the bum to someone else..

I’ve been tearing things open after ignoring the “dangerous if opened” stickers since I was 8 years old. I’m in my 30s, you’d think something would have caused me harm by now, but no.

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.

Re: Fixing a loud PSU fan without dying

#13

Post by PaulKeeble »

I am pretty certain that the G2 Noctua fans will start at 5V and they also in the 4 pin model will turn off at 0-19% and turn on at 20%. Its a bit of a shame Noctua don't make 2 pin fans anymore but it is possible on the latest most efficient models to get the low start voltage.

The G1 Noctua fans don't, I have a 120mm still in my case that is a decade or so old and it starts at a bit under 7V, but all the G2 140mm will start at 5V IIRC the Noctua presentations on this. Wish it was laid out in the specifications however.

Re: Fixing a loud PSU fan without dying

#14

Post by ahartmetz »

PaulKeeble wrote: post #10
ahartmetz wrote: post #9

Earlier quoted context omitted.

If you need pretty good fans for cheap as dirt, there is also Arctic Cooling.

They just never last. Arctic fans perform really well especially for their price but they all seem to develop problems. I have probably bought about 15 different Arctic fans from the F and P range and none of them survived 5 years, most were dead or developed noise within 1-2 years. Noctua on the other hand the old 80mm fan from the early 2000s still works just fine and remains quiet. Noctua fans are crazy reliable,…

Arctic fans seem to last 10+ years for me. I haven't bought any recently though and I run them at 500 rpm or so, that's my strategy: many and large fans, running slowly.

Re: Fixing a loud PSU fan without dying

#15

Post by jakeinspace »

doubled112 wrote: post #7
sonofhans wrote: post #3

An 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…

I ran into this same setup with a microwave that failed in a few months after purchase and Walmart. Tried to deal with the manufacturer, but they couldn’t help and sent me to the retailer. Went to the store, popped it up on the counter, had a short conversation and got the expected “you have to deal with the manufacturer”. Is there anything else I can help you with today? Actually yes. Can you throw that out for me?…

My experience with cheap modern microwave failures has been the door sensor failing, which for safety ofc prevents the magnetron from running. I had one fail in about 2 months, thankfully fixable with a $10 sensor and 15 minute of work. Same goes for a lot of appliances, repaired a dryer that had its door sensor fail (in fact, they all tend to use identical door sensors as far as I've seen, dryers and washing machines and microwaves).

Re: Fixing a loud PSU fan without dying

#16

Post by userbinator »

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.

Re: Fixing a loud PSU fan without dying

#17

Post by cmurf »

Check your credit card agreement. Some cards have a "purchase return protection" for when a retailer won't take back a product.

It's kindof a gimmick because it's easy to forget you have it, but if you have it, use it.

Re: Fixing a loud PSU fan without dying

#18

Post by scottlamb »

jojobas wrote: post #12
doubled112 wrote: post #8

Earlier quoted context omitted.

I’ve been tearing things open after ignoring the “dangerous if opened” stickers since I was 8 years old. I’m in my 30s, you’d think something would have caused me harm by now, but no.

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.

Re: Fixing a loud PSU fan without dying

#19

Post by serf »

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.

Re: Fixing a loud PSU fan without dying

#20

Post by stavros »

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.

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.
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