Two ATX Power Supplies with unstable 5V standby. How to fix them? ATX PSU Repair LER

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  • เผยแพร่เมื่อ 11 ธ.ค. 2024

ความคิดเห็น • 30

  • @LearnElectronicsRepair
    @LearnElectronicsRepair  3 ปีที่แล้ว +1

    Capacitance Meter XC6013L €14.72
    www.aliexpress.com/item/32656340440.html?spm=a2g0o.productlist.0.0.19772f8aVxL5mM&algo_pvid=0b9feec6-3a17-4006-839a-88afa24fa1e0&algo_exp_id=0b9feec6-3a17-4006-839a-88afa24fa1e0-0&pdp_ext_f=%7B%22sku_id%22%3A%2259775890656%22%7D
    ESR Meter MESR-100 €31.76
    www.aliexpress.com/item/1005003291550047.html?spm=a2g0o.productlist.0.0.3058269dAJk5BX&algo_pvid=b49375d7-ba90-451a-80af-233dd54ead60&algo_exp_id=b49375d7-ba90-451a-80af-233dd54ead60-6&pdp_ext_f=%7B%22sku_id%22%3A%2212000025048760972%22%7D
    Modified ATX PSU Analyzer
    th-cam.com/video/yw747J-9F1s/w-d-xo.html

    • @trone32
      @trone32 3 ปีที่แล้ว

      Just ordered the ESR meter thanks for that

    • @LearnElectronicsRepair
      @LearnElectronicsRepair  3 ปีที่แล้ว +2

      @@trone32 You are going to find that a really useful bit of kit. And not only for testing capacitors. If you didn't already see them, here are two videos where I demonstrate how to find a short circuit mosfet in a multiphase VRM with the ESR meter.
      How to find short circuit VRM MOSFET with an ESR meter
      th-cam.com/video/i8TudEfD2Ao/w-d-xo.html
      How to find a short circuit on a GPU with an ESR meter
      th-cam.com/video/5cG2aJwNoAw/w-d-xo.html
      Enjoy, and let us all know what you think of your new ESR meter when it arrives 🙂

    • @peddersoldchap
      @peddersoldchap 2 ปีที่แล้ว

      The MERS100 costs €100 now (5 months later). :(

    • @chinnarao326
      @chinnarao326 ปีที่แล้ว

      Sir! My Dell 6Pin SMPS Series Lamp 5 Times on off Sir. DC 12V Directed Sir. Where the Problem Sir. -- ChinnaRao Paderu Andhrapradesh

  • @boblewis5558
    @boblewis5558 ปีที่แล้ว +3

    I never cease to be amazed by the complete lack of general mechanical engineering understanding of my erstwhile electronic engineering colleagues when it comes to the specification and use of fans in electronic equipment.
    The basic 12v computer fan has varied little in the 47 years since I started my electronic engineering career and there are still only two basic forms: sleeve bearing or ball bearing types.
    Using a sleeve bearing fan (the cheapest and hence most ubiquitous) in ANYTHING other than a vertical orientation displays a complete lack of understanding of basic engineering principles ... A sleeve (bush) bearing can ONLY provide a proper bearing action when it is horizontal, i.e. when the fan is vertical!
    Yet, despite this they can often be found mounted horizontally! This means the bush provides virtually zero support to the fan shaft!
    Worse, the ONLY vertical support for the fan comes either from the fibre washer at the inside end of the fan shaft resting on the bottom of the fan shaft mounting when the fan blades are facing upwards. Or worse still, when hanging from the end of the shaft on another fibre washer or even JUST the circlip holding the fan in situ on the shaft!
    Anyone wishing to extend the life of such fans significantly under these conditions would do well to replace such horizontally mounted fans with PROPER bearing support via ball bearing ones, ESPECIALLY those as used in the supply shown in your video! Yes they are a bit noisier AND a bit more expensive but they do have the engineering to last!

  • @LearnElectronicsRepair
    @LearnElectronicsRepair  3 ปีที่แล้ว +2

    I noticed further to confuse, the Agiler PSU says on the label, Total Output 400W, then on the Orange Banner it says ATX 450W Power Supply. Which is more than the total output power. I was interested how they came to 450W so I calculated the wattage for the +12V, -12V, -5V and 5VSB based on the label, then added that to the 200W max for 3.3V and 5V combined... and that totaled 433W. So I just can't work it out.

    • @johncollins5552
      @johncollins5552 ปีที่แล้ว

      There's the tolerance of components plus or minus ten percent is an electronics norm really unless you buy high end stuff that would be 5 per cent.

  • @peddersoldchap
    @peddersoldchap 2 ปีที่แล้ว +2

    The Power Good pin has to be set to high in a specific time interval after the PS-ON pin is set to low.
    It's mandatory by the ATX standard.

  • @jasonbevan6275
    @jasonbevan6275 3 ปีที่แล้ว +1

    I did a bit of research after my comment about the 1/2 AT supply on one of your previous videos, and that connector is an ATX rev 2.02/2.03 motherboard and ATX12V 1.X auxiliary power connector - used to support motherboards drawing 300W or more in about 2005. It wasn't widely adopted on Motherboards but quite a few PSUs had it - including an old Thermaltake of mine.

    • @LearnElectronicsRepair
      @LearnElectronicsRepair  3 ปีที่แล้ว

      Thanks Jason, it's good to get to the bottom of the mystery in the end

    • @uploadJ
      @uploadJ ปีที่แล้ว

      I've seen that on an older Dell, made back in the early 2000's ...

  • @saarike
    @saarike 3 ปีที่แล้ว +1

    Simply excellent! My humble thanks. 👍

  • @daz41262010
    @daz41262010 ปีที่แล้ว

    great fixes :) also some really cool tips on this video :)

  • @carlopasswords7083
    @carlopasswords7083 3 ปีที่แล้ว

    Thanks for sharing your knowledge

  • @Dutch_off_grid_homesteading
    @Dutch_off_grid_homesteading ปีที่แล้ว

    Heya if you know were to look for you will come far

  • @gloubiboulgazeblob
    @gloubiboulgazeblob ปีที่แล้ว

    Hi, nice video, as usual 🙂. Thanks for sharing knowledge.
    [ QUESTION ] What is unit "ms" used for POWER GOOD ? Milliseconds ???

  • @wilsard
    @wilsard ปีที่แล้ว

    in several supplies of mine, i've taken out the 220/110 switch, and connected them to permanently 110. i hate that switch.

  • @enriconapolitano4321
    @enriconapolitano4321 3 ปีที่แล้ว

    Thanks

  • @niceeleven7838
    @niceeleven7838 3 ปีที่แล้ว

    In standby section i got reading on 1st powersupply (big diode) 3.7v and 10v on second powersupply, i get 3.7v in standby(purple wire) and also green wire, mosfet is good, what do you think is the problem

    • @LearnElectronicsRepair
      @LearnElectronicsRepair  3 ปีที่แล้ว

      1. Check or change the capacitors on the Standby and other (10CV )voltage rail.
      2. Have a look for small value electrolytics around the Standby PWM generator on the high voltage side (could be an IC like TOPxxx or similar, or two transistors forming an oscillator to generate 5VSB - depends on the circuit design) Check or change any capacitors here
      3. Check the feedback circuit. With the PSU off - use you DMM in diode test ode and measure across opto-isolator on the high voltage side (the transistor side of the opto-isolator). You want the +ve meter lead to the collector - use the datasheet to find it or check if one pin of the opto-isolator transistor connects to negative of the big main smoothing capacitor. If it does the collector is the other pin No take a bench PSU - set it to about 4V and connect the +ve of the bench PSU to the purple wire, negative to ground. The DMM should read open circuit - now increase the voltage slowly - when it reaches a bit over 5V your DMM should show the transistor turning on - and at about 5.5V the transistor should be fully on and read short, more or less
      If 3. works as described then change the IC that generated 5V standby (if there is one)
      If 3. does not work as described
      a: look for a three pin device marked TL431 (or similar like KIA471, F431, etc). This is the voltage reference - you need to remove it and test it - I made a video showing how to do it
      th-cam.com/video/W66yahrJA5U/w-d-xo.html
      b: remove and test the opto-isolator
      c: reverse engineer the circuit between the purple wire, Optoisolator LED and TL431 - could be open circuit or faulty resistor here
      I hope that helps, let us know how you go on.

    • @niceeleven7838
      @niceeleven7838 3 ปีที่แล้ว

      @@LearnElectronicsRepair i'll will try all the suggeztion and get back to you once i fugure it out, many thanks and more blessing to come.

  • @FUNTHE1
    @FUNTHE1 3 ปีที่แล้ว

    Hi, I also have a source that on the blue wire of -12 v has only -11 v, what can I do? I also replaced a capacitor .... please

  • @leagueunited8841
    @leagueunited8841 2 ปีที่แล้ว

    Sir.. i hope u can give me an idea on how to fix my PSU. When i turn on my psu with luck its good. But when i turn on again it doest powering on anymore. And then the next day its powering on again. And when i off it doest power on again. How is that? Thanks hoping for your kind response.

    • @johncollins5552
      @johncollins5552 ปีที่แล้ว

      A bad solder joint or failing capacitor most likely.

  • @juancosta200
    @juancosta200 3 ปีที่แล้ว

    First