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Opening a SFX PSU to clean it. Risks?

Discussion in 'Power Supplies' started by gizmo1990, Jul 3, 2018.

  1. gizmo1990

    Hitman

    Joined: Aug 1, 2003

    Posts: 761

    I've an over 5 year old Silverstone 450W SFX psu, which I removed from my old machine recently. Works fine, a great little psu. I'd like to put it back in a new build, but it looks like it's got a fair amount of dust build up. I'm considering opening up the case to give it a good clean.

    Has anyone done this? What are the pros and cons? Is it easy to screw something or are they fairly forgiving things to open and clean. I'd only give it a good going over with some compressed air, I wouldn't bother replacing the fan or anything like that.

    Any advice greatly appreciated.
     
  2. PiKe

    Capodecina

    Joined: Oct 18, 2002

    Posts: 22,718

    Location: Lake District

    Just don't touch anything inside with your fingers unless its been removed from the mains for at least 24 hours.
     
  3. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 1,397

    Use an compressed can air duster / compressor outside or a decent hoover, shouldn't need to open it up.
     
  4. moogle

    Wise Guy

    Joined: Nov 4, 2006

    Posts: 2,118

    Location: London

    Use the air blower from outside. A decent one should be able to dislodge all the dust unless you ran it in a kitchen with greasy air or are a heavy smoker.
     
  5. Admiral Huddy

    Don

    Joined: Feb 17, 2003

    Posts: 28,428

    Location: Chelmsford & Broadgate

    This.. with some help from a light clean paintbrush.
     
  6. gizmo1990

    Hitman

    Joined: Aug 1, 2003

    Posts: 761

    Thanks for the replies guys. @SupraWez I'm not sure that will do a good enough job tbh. I would presume I'd likely just end up blowing dust more deeply into the case? Plus there's the possibility of causing an issue with dust shorting something because of it.
     
  7. samcat

    Mobster

    Joined: Nov 8, 2002

    Posts: 2,856

    Location: Near Bristol, Uk

    Dead easy to open and clean. Obviously only do it with it totally unplugged.
    Be aware that some caps can hold charge for some time, so leave in unplugged for a few days before opening and still tread carefully, dont touch internals... Act like it can kill you with one bad touch. After a few days unplugged the caps will be empty, but better to be safe than sorry.

    Do it outside, dust goes everywhere!

    Soft clean paintbrush to loosen it up, canned air to blast it.

    Screw it back together.

    Dead easy, will take about 10 minutes if you are taking your time.
     
  8. EsaT

    Mobster

    Joined: Jun 6, 2008

    Posts: 3,900

    Location: Finland

    I guess it's either of these particular models so indeed would be hard to clean without opening:
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=196
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story5&reid=319

    All good PSUs have bleeder resistors for primary caps, so after couple hours disconnected from wall there shouldn't be much charge left.
    But as that PSU has good old colour coded wires you can attach 24 pin cable and short green wire to black with paperclip etc.
    That "orders" PSU to start further speeding draining of primary capacitor.
    All other capacitors simply can't store much any energy/have low voltage needing touching them with tongue for anything to happen.
     
  9. gizmo1990

    Hitman

    Joined: Aug 1, 2003

    Posts: 761

    Thanks again everyone for the replies.

    @EsaT Thanks for that, that's incredibly useful. Mine is the one in the first link. However, it does looks mighty fiddly to open up doesn't it. I'm erring on the side of just blasting it from the outside instead now! Decisions decisions. Anyone wanna tell me it doesn't look too bad to open and it'll go back together fine? :);)
     
  10. EsaT

    Mobster

    Joined: Jun 6, 2008

    Posts: 3,900

    Location: Finland

    Would be really hard to get dust out of there without such air pressure which isn't exactly gentle for small components.
    Also high pressure air can easily overspeed fan damaging its bearing.
    And certainly would want to make sure dust isn't blocking airflow to those cheaper capacitors.

    Looks like it has screws on top and bottom and one screw in cabling end attaching cover to heatsink for using it in cooling.
    With fan's cable limiting how far "cover" can be pulled.
    https://www.pcper.com/reviews/Cases...SF-450-watt-Power-Supply-Review/Detailed-Look
    Heck, it's age would warrant taking look at those capacitors.
     
  11. gizmo1990

    Hitman

    Joined: Aug 1, 2003

    Posts: 761

    Thanks again @EsaT I've just done the paperclip on the 4th(green) and 5th(black) wires to power it on to check it's still working and it powers on fine. Are you saying that leaving the paperclip there for a while (power plug in or out?) is effectively speeding up the discharging of the capacitor? If so how ong do you reckon I should leave it for? I've a mind to do this asap now so would rather not wait a few days.
     
  12. EsaT

    Mobster

    Joined: Jun 6, 2008

    Posts: 3,900

    Location: Finland

    With cord disconnected from wall that will certainly empty primary capacitor for as long as PSU's electronics can operate on remaining charge.
    With that bleeder resistor doing rest there really shouldn't be much any kind charge left after hour or two of waiting.
     
  13. PiKe

    Capodecina

    Joined: Oct 18, 2002

    Posts: 22,718

    Location: Lake District

    Or you just unplug it and then press the power button on the computer - does that same thing.
     
  14. gizmo1990

    Hitman

    Joined: Aug 1, 2003

    Posts: 761

    Job done.:) Opened far easier than I thought it would for its size. There was a heck of a lot of dust inside, I really don't think external cleaning would have shifted even half of it. The capacitors look good, though I'm no expert. I was just checking for any signs of bulging. Turned it on and it all starts up ok.

    I was a bit concerned when @EsaT mentioned the fan bearings could be damaged, as I'd previously use the vaccum externally earlier, which sped the fan up a fair amount. However, it sounds pretty good, ie couldn't hear it much above a light whirring.

    I intend on doing a voltage check when I come to putting the new build together, just to be on the safe side. But I think it was totally worth it opening it up. I feel much better about putting it in a case with new componants.now.

    Huge thanks again everyone for your input!:)
     
  15. EsaT

    Mobster

    Joined: Jun 6, 2008

    Posts: 3,900

    Location: Finland

    Enough dust would be even minor fire risk, if something heats up too much or some semiconductor desides to blow up causing spark.
    Though would have to be lots of dust for it to be able to do more than give little smoke.
    (enough heat and plastics of fan could melt and start burning)