5 ms·

Fixing a loud PSU fan without dying

45 points by sprawl_ 1y ago

mkayokay 1y ago
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 price of a modern gaming PC, that's nothing (also avoiding not risking your life).
- jojobas 1y ago
  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..
  - doubled112 1y ago
    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.
    - jojobas 1y ago
      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.
      - scottlamb 1y ago
        > 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.
        jojobas 1y ago
        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.
        scottlamb 1y ago
        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.
        jojobas 1y ago
        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.
        account42 1y ago
        That's more than an order of magnitude less than fatalities from cars. In my book, that puts it into "be careful" territory but far from "don't even think about it".
        jojobas 1y ago
        Nearly everyone deals with roads every single day. Very few people disassemble electric devices per day. The risk base is not comparable. Also https://xkcd.com/795/ https://xkcd.com/795/
      - account42 1y ago
        A lot of the risk is simply overstated. Yes, bad things can happen but that also goes for crossing the road yet we don't limit that to certified professionals. Just have some basic understanding of electricity, common sense, don't attempt the work while tired and you'll be fine.
- tcdent 1y ago
  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.
  - ahartmetz 1y ago
    If you need pretty good fans for cheap as dirt, there is also Arctic Cooling.
    - PaulKeeble 1y ago
      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, they cost more too but I would suspect over the life of the fan they end up similar priced or cheaper.
      - ahartmetz 1y ago
        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.
    - mrbigbob 1y ago
      while arctic make fairly good high performing fans for cheap their bearings/acoustics are kind of bad. i bought 5 of the original p12 max fans with the ball bearings. they all made a chirping noise at various rpms (even after getting 5 new ones from arctic). the new p12 pro fans perform great but around 1200 rpms the motor is very loud and annoying really wish arctic would now focus on the acoustics of their fans because its there weakest point. i wouldnt mind spending a bit more per fan if the sound profile wasnt just straight terrible which personally theirs are to me at the moment
  - 1y ago
- hobs 1y ago
  Hilarious to read this on "hacker news" - replacing a standard fan is too dangerous! This is not styropyro.
  - ycombinatrix 1y ago
    PSU capacitors can kill you, even after being disconnected from mains power.
  - victorhooi 1y ago
    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 supplies...and well, electrical arc, boom, you can guess the rest. And in a domestic situation, a 4" cooling fan (yes, I know, larger) stopped suddenly due to a motor issue, and send flying bits of plastic shrapnel around (always wear eye protection!). This isn't quite like tinkering with your little Arduino board, or Raspberry Pi. If you did read the article =(.... I think that's a bit arrogant and disingenuous to make fun of people saying you should be cautious around things that are connected to AC mains, or that involve capacitors.
    - umbra07 1y ago
      > 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?
    - hobs 1y ago
      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.
sonofhans 1y ago
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 to diagnose and try to repair it. Here’s the kicker: Usually repairs take up to 20 business days (including delivery time), but could take slightly longer Everyone knows electronic devices tend to die early or last forever. Cooler Master and Amazon are working a shitty dodge here, and I bet they avoid most DOA warranty claims because of it.
- doubled112 1y ago
  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? The confusion on the guy’s face was great. Spent more than enough time on the $100 microwave. Their problem now.
  - jakeinspace 1y ago
    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).
    - abrugsch 1y ago
      My personal experience with a modern microwave (they mostly seem to be the same design internally, coming from the same chassis with the same electronics just a different button panel) was that the internal light bulb blowing generated a surge (it was a mains voltage bulb) that wasn't fused so the next nearest thing in the mains circuit was a trace on the motherboard that vaporized. There is no way of easily changing this bulb (inside the main casing with no access panel for the bulb) so for want of a single in-line fuse, the entire microwave was rendered scrap[0] by the lifetime of a light bulb. [0] - Except for the fact that I care not for electrical safety "DO NOT OPEN" warnings of doom due to being actually competent with handling high voltage equipment and being able to do a board level repair on the burned out trace without touching the very large capacitors associated with the very high voltage side controlling the magnetron...
PaulKeeble 1y ago
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.
userbinator 1y ago
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.
- serf 1y ago
  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.
  - magicalhippo 1y ago
    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.
    - jijijijij 1y ago
      I think magnetic bearings necessarily also got touching parts.
  - userbinator 1y ago
    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.
- stavros 1y ago
  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.
  - 1y ago
cmurf 1y ago
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.
ziml77 1y ago
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?
- duskwuff 1y ago
  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.
  - userbinator 1y ago
    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.
    - analog31 1y ago
      Beware. I took a poke from the focus anode of a CRT when I had a job repairing mainframe terminals in the early 80s. I thought I had discharged it, but apparently I didn't. I had to sit down in a quiet room for the rest of the work day, before I could function again. It was probably 13 kV, which was typical for monochrome displays back in the day. Also, anything in a CRT television can kill you because TV's tended to have a "hot" chassis. The repairmen always plugged a TV into an isolation transformer so they could ground its chassis while working on it. There's a lot of counterintuitive things about those old electronics due to clever cost reductions.
m463 1y ago
I learned about fans many yea^H^H^H decades ago when I had a sun external scsi disk box. One day at Fry's Electronics I found they sold external scsi cases. So I bought a case and a cheaper bare scsi drive and hooked it to my sun. The fan was quieter too! and after a few months, the fan started getting louder. and louder. and then one day when the drive seemed to stop responding, I found it had failed. sun fans were annoyingly loud, but they had one interesting property: THEY ALWAYS SPUN.
shmerl 1y ago
Get PSU from original manufacturers instead, someone like Seasonic. Most common brands simply repackage stuff and not really the best quality.
- rpcope1 1y ago
  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.
  - shmerl 1y ago
    I noticed some of their models are often out of stock. I really hope they aren't quitting.
rpcope1 1y ago
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.
sandreas 1y ago
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.
theandrewbailey 1y ago
I've replaced at least 2 PSU fans, all without incident. The last time, I bought a pack of fans with that specific tiny connector, making the repair simpler.

45 points by sprawl_ 1y ago

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 price of a modern gaming PC, that's nothing (also avoiding not risking your life).

jojobas 1y ago
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..
- doubled112 1y ago
  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.
  - jojobas 1y ago
    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.
    - scottlamb 1y ago
      > 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.
      - jojobas 1y ago
        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.
        scottlamb 1y ago
        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.
        jojobas 1y ago
        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.
        account42 1y ago
        That's more than an order of magnitude less than fatalities from cars. In my book, that puts it into "be careful" territory but far from "don't even think about it".
        jojobas 1y ago
        Nearly everyone deals with roads every single day. Very few people disassemble electric devices per day. The risk base is not comparable. Also https://xkcd.com/795/ https://xkcd.com/795/
    - account42 1y ago
      A lot of the risk is simply overstated. Yes, bad things can happen but that also goes for crossing the road yet we don't limit that to certified professionals. Just have some basic understanding of electricity, common sense, don't attempt the work while tired and you'll be fine.
tcdent 1y ago
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.
- ahartmetz 1y ago
  If you need pretty good fans for cheap as dirt, there is also Arctic Cooling.
  - PaulKeeble 1y ago
    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, they cost more too but I would suspect over the life of the fan they end up similar priced or cheaper.
    - ahartmetz 1y ago
      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.
  - mrbigbob 1y ago
    while arctic make fairly good high performing fans for cheap their bearings/acoustics are kind of bad. i bought 5 of the original p12 max fans with the ball bearings. they all made a chirping noise at various rpms (even after getting 5 new ones from arctic). the new p12 pro fans perform great but around 1200 rpms the motor is very loud and annoying really wish arctic would now focus on the acoustics of their fans because its there weakest point. i wouldnt mind spending a bit more per fan if the sound profile wasnt just straight terrible which personally theirs are to me at the moment
- 1y ago
hobs 1y ago
Hilarious to read this on "hacker news" - replacing a standard fan is too dangerous! This is not styropyro.
- ycombinatrix 1y ago
  PSU capacitors can kill you, even after being disconnected from mains power.
- victorhooi 1y ago
  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 supplies...and well, electrical arc, boom, you can guess the rest. And in a domestic situation, a 4" cooling fan (yes, I know, larger) stopped suddenly due to a motor issue, and send flying bits of plastic shrapnel around (always wear eye protection!). This isn't quite like tinkering with your little Arduino board, or Raspberry Pi. If you did read the article =(.... I think that's a bit arrogant and disingenuous to make fun of people saying you should be cautious around things that are connected to AC mains, or that involve capacitors.
  - umbra07 1y ago
    > 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?
  - hobs 1y ago
    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.

sonofhans 1y ago

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 to diagnose and try to repair it. Here’s the kicker: Usually repairs take up to 20 business days (including delivery time), but could take slightly longer Everyone knows electronic devices tend to die early or last forever. Cooler Master and Amazon are working a shitty dodge here, and I bet they avoid most DOA warranty claims because of it.

doubled112 1y ago
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? The confusion on the guy’s face was great. Spent more than enough time on the $100 microwave. Their problem now.
- jakeinspace 1y ago
  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).
  - abrugsch 1y ago
    My personal experience with a modern microwave (they mostly seem to be the same design internally, coming from the same chassis with the same electronics just a different button panel) was that the internal light bulb blowing generated a surge (it was a mains voltage bulb) that wasn't fused so the next nearest thing in the mains circuit was a trace on the motherboard that vaporized. There is no way of easily changing this bulb (inside the main casing with no access panel for the bulb) so for want of a single in-line fuse, the entire microwave was rendered scrap[0] by the lifetime of a light bulb. [0] - Except for the fact that I care not for electrical safety "DO NOT OPEN" warnings of doom due to being actually competent with handling high voltage equipment and being able to do a board level repair on the burned out trace without touching the very large capacitors associated with the very high voltage side controlling the magnetron...

PaulKeeble 1y ago

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.

userbinator 1y ago

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.

serf 1y ago
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.
- magicalhippo 1y ago
  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.
  - jijijijij 1y ago
    I think magnetic bearings necessarily also got touching parts.
- userbinator 1y ago
  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.
stavros 1y ago
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.
- 1y ago

cmurf 1y ago

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.

ziml77 1y ago

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?

duskwuff 1y ago
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.
- userbinator 1y ago
  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.
  - analog31 1y ago
    Beware. I took a poke from the focus anode of a CRT when I had a job repairing mainframe terminals in the early 80s. I thought I had discharged it, but apparently I didn't. I had to sit down in a quiet room for the rest of the work day, before I could function again. It was probably 13 kV, which was typical for monochrome displays back in the day. Also, anything in a CRT television can kill you because TV's tended to have a "hot" chassis. The repairmen always plugged a TV into an isolation transformer so they could ground its chassis while working on it. There's a lot of counterintuitive things about those old electronics due to clever cost reductions.

m463 1y ago

I learned about fans many yea^H^H^H decades ago when I had a sun external scsi disk box. One day at Fry's Electronics I found they sold external scsi cases. So I bought a case and a cheaper bare scsi drive and hooked it to my sun. The fan was quieter too! and after a few months, the fan started getting louder. and louder. and then one day when the drive seemed to stop responding, I found it had failed. sun fans were annoyingly loud, but they had one interesting property: THEY ALWAYS SPUN.

shmerl 1y ago

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

rpcope1 1y ago
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.
- shmerl 1y ago
  I noticed some of their models are often out of stock. I really hope they aren't quitting.

rpcope1 1y ago

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.

sandreas 1y ago

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.

theandrewbailey 1y ago

I've replaced at least 2 PSU fans, all without incident. The last time, I bought a pack of fans with that specific tiny connector, making the repair simpler.