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    ATX PSU Tester Analyzer modification / upgrade

    Hi guys
    I have one of these ATX PSU Analyzers/Analysers Tester

    https://www.aliexpress.com/item/3280...73275478%22%7D

    The analyzer is very good for testing ATX power supplies - if they work! But it's pretty useless for testing them if they faulty. Which kinda defeats the object.

    The problem is caused by the fact the Analyser is powered from the 12V on the 20/24pin ATX connector. So for example if you have 5V Standby and nothing else, the analyser is dead, it does not power on. Even worse you can have all voltages present apart from 12V and the analyser still will not power on - leading you to believe you have a dead PSU.

    I recently wasted over two hours trying to fix a 'dead' PSU where I just could not find anything wrong, only to realise in the end it was working, apart from an open circuit track on the 12V output

    So I decided to modify the Analyser so that it will power up and work if any voltage is coming out of the ATX PSU, whether it is 5VSB, 3.3V, 5V OR 12V

    In fact it will now work with just 2.5V on any one voltage rail

    The modification cost just €0.70 in parts and fits inside the existing housing.

    If you have one of these analysers and would like to make it actually useful, then here is how I did it

    https://www.youtube.com/watch?v=yw747J-9F1s
    Follow me on YouTube
    ------------------
    Learn Electronics Repair
    https://www.youtube.com/channel/UCFX...R8UZ2vg/videos

    #2
    Re: ATX PSU Tester Analyzer modification / upgrade

    interesting,
    i have one of those and thought it was using the 5v standby rail - gonna have to look in it now.
    i may also fit a switch on the control line to switch the main psu on and off.

    Comment


      #3
      Re: ATX PSU Tester Analyzer modification / upgrade

      would make sense if it were using 5VSB, because ATX PSUs won't work at all if 5VSB is dead as it's needed for !PSON ... silly to run it off of 12V...

      Comment


        #4
        Re: ATX PSU Tester Analyzer modification / upgrade

        Originally posted by dicky96 View Post
        Hi guys
        I have one of these ATX PSU Analyzers/Analysers Tester

        https://www.aliexpress.com/item/3280...73275478%22%7D

        The analyzer is very good for testing ATX power supplies - if they work! But it's pretty useless for testing them if they faulty. Which kinda defeats the object.

        The problem is caused by the fact the Analyser is powered from the 12V on the 20/24pin ATX connector. So for example if you have 5V Standby and nothing else, the analyser is dead, it does not power on. Even worse you can have all voltages present apart from 12V and the analyser still will not power on - leading you to believe you have a dead PSU.

        I recently wasted over two hours trying to fix a 'dead' PSU where I just could not find anything wrong, only to realise in the end it was working, apart from an open circuit track on the 12V output

        So I decided to modify the Analyser so that it will power up and work if any voltage is coming out of the ATX PSU, whether it is 5VSB, 3.3V, 5V OR 12V

        In fact it will now work with just 2.5V on any one voltage rail

        The modification cost just €0.70 in parts and fits inside the existing housing.

        If you have one of these analysers and would like to make it actually useful, then here is how I did it

        https://www.youtube.com/watch?v=yw747J-9F1s
        Thanks for posting this information this will help me a lot
        Last edited by sam_sam_sam; 09-09-2021, 07:42 PM.
        9 PC LCD Monitor
        6 LCD Flat Screen TV
        30 Desk Top Switching Power Supply
        10 Battery Charger Switching Power Supply for Power Tool
        6 18v Lithium Battery Power Boards for Tool Battery Packs
        1 XBox 360 Switching Power Supply and M Board
        25 Servo Drives 220/460 3 Phase
        6 De-soldering Station Switching Power Supply 1 Power Supply
        1 Dell Mother Board
        15 Computer Power Supply
        1 HP Printer Supply & Control Board * lighting finished it *


        These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

        1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
        2 Hem Saw Computer Stack Board

        All of these had CAPs POOF
        All of the mosfet that are taken out by bad caps

        Comment


          #5
          Re: ATX PSU Tester Analyzer modification / upgrade

          If you have one stuck using 12V I'd suggest trying to just make it work of 5VSB. Probably a lot simpler than any other solution? Unfortunately I don't have such unit to see what the "simplest" "fix" would be...

          Comment


            #6
            Re: ATX PSU Tester Analyzer modification / upgrade

            Originally posted by eccerr0r View Post
            If you have one stuck using 12V I'd suggest trying to just make it work of 5VSB. Probably a lot simpler than any other solution? Unfortunately I don't have such unit to see what the "simplest" "fix" would be...
            What about powering it with an external 5 volt power supply

            I have a couple of them I will try doing this and let you how well it works doing it this way
            Last edited by sam_sam_sam; 09-09-2021, 07:43 PM.
            9 PC LCD Monitor
            6 LCD Flat Screen TV
            30 Desk Top Switching Power Supply
            10 Battery Charger Switching Power Supply for Power Tool
            6 18v Lithium Battery Power Boards for Tool Battery Packs
            1 XBox 360 Switching Power Supply and M Board
            25 Servo Drives 220/460 3 Phase
            6 De-soldering Station Switching Power Supply 1 Power Supply
            1 Dell Mother Board
            15 Computer Power Supply
            1 HP Printer Supply & Control Board * lighting finished it *


            These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

            1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
            2 Hem Saw Computer Stack Board

            All of these had CAPs POOF
            All of the mosfet that are taken out by bad caps

            Comment


              #7
              Re: ATX PSU Tester Analyzer modification / upgrade

              why?
              if the 5v standby is missing then everything is dead and you have nothing to meter anyway.

              Comment


                #8
                Re: ATX PSU Tester Analyzer modification / upgrade

                Originally posted by stj View Post
                why?
                if the 5v standby is missing then everything is dead and you have nothing to meter anyway.
                All I am asking for now would it work if powered separately for now
                Would there be any issues to be concerned about doing it this way
                9 PC LCD Monitor
                6 LCD Flat Screen TV
                30 Desk Top Switching Power Supply
                10 Battery Charger Switching Power Supply for Power Tool
                6 18v Lithium Battery Power Boards for Tool Battery Packs
                1 XBox 360 Switching Power Supply and M Board
                25 Servo Drives 220/460 3 Phase
                6 De-soldering Station Switching Power Supply 1 Power Supply
                1 Dell Mother Board
                15 Computer Power Supply
                1 HP Printer Supply & Control Board * lighting finished it *


                These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                2 Hem Saw Computer Stack Board

                All of these had CAPs POOF
                All of the mosfet that are taken out by bad caps

                Comment


                  #9
                  Re: ATX PSU Tester Analyzer modification / upgrade

                  well - i'll open one and take pictures for you.
                  i'm personally more interested if i can find room inside for a rocker switch.

                  Comment


                    #10
                    Re: ATX PSU Tester Analyzer modification / upgrade

                    If you power it separately, the major drawback is that you'd need another outlet or a battery ...

                    Can't think of any reason not to power off of 5VSB other than if your meter draws more than 100mA - because ATX1.0 did not specify much current for 5VSB.

                    Hopefully bad cap ripple on 5VSB doesn't blow the tester...

                    Comment


                      #11
                      Re: ATX PSU Tester Analyzer modification / upgrade

                      The way I modified it was all internal and only cost €0.76 in parts

                      So now it will power up as long as any voltage rail has at least 2.5V. That could be further reduced to about 2.15V if using Schottky diodes

                      I also considered the fact that if it would work from 5VSB then that would be good enough as it is not possible to have any other rails if 5VSB is missing...... or is it?

                      I can conceivably see a case where this would not be true - and I mention this in the video

                      Most ATX PSU I looked at have two windings, or taps, on the 5V STB transformer. The second winding/tap is typically 12V-24V with it's own rectifier diode and capacitor, and is used to power the PWM IC and associated transistor circuit that drives the base of the output transistors via a transformer

                      So if there was a fault where there was an open pcb circuit track or similar between the 5VSB transformer and the purple ATX wire, it is likely that the 12V-24V internal rail would still be there.

                      And seeing as this anaylser starts the ATX by physically connecting the green wire to ground, and needs no voltage on 5VSB to do that - it is at least possible you could have an ATX PSU that has no 5VSB but still powers up with all other voltages present when connected to the analyser.
                      Follow me on YouTube
                      ------------------
                      Learn Electronics Repair
                      https://www.youtube.com/channel/UCFX...R8UZ2vg/videos

                      Comment


                        #12
                        Re: ATX PSU Tester Analyzer modification / upgrade

                        I really don't know why they used 12V to power initially, seems that you should be able to use 5VSB for nearly no additional cost, granted it will require it to be at least 3 or 4 volts for it to power whatever chips the tester uses. As said multiple times, ATX PSUs that don't have 5VSB working cannot turn on because that's what powers the !PSON - for both isolation and for keeping voltages within reasonable limits. Note that in the normal case, motherboards need 5VSB to power their switching circuitry, can't assert !PSON without any power.

                        It depends on the PSU design whether it uses two taps... isolation can happen with transformers or optoisolators.

                        Comment


                          #13
                          Re: ATX PSU Tester Analyzer modification / upgrade

                          If it will work from 5VSB, you could always have diode-isolated "battery back-up":


                          PeteS in CA

                          Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
                          ****************************
                          To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
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                          Comment


                            #14
                            Re: ATX PSU Tester Analyzer modification / upgrade

                            not that brand though - no DuraLeak.

                            Comment


                              #15
                              Re: ATX PSU Tester Analyzer modification / upgrade

                              Originally posted by eccerr0r View Post
                              If you power it separately, the major drawback is that you'd need another outlet or a battery ...

                              Can't think of any reason not to power off of 5VSB other than if your meter draws more than 100mA - because ATX1.0 did not specify much current for 5VSB.

                              Hopefully bad cap ripple on 5VSB doesn't blow the tester...
                              The reason I asked the question is if there is an issue with the standby circuit and provide more than 5 volts and you bypass the regulator because of low voltage rating for the meter parameters you might damage the tester

                              But in general I would agree with you that you could power it with the standby power supply output side but how do protect the tester from incorrect voltage from the standby circuit if has an issue

                              I would think that the meter module itself might not draw much current but the tester will put a load on the switching power supply output side of it
                              Last edited by sam_sam_sam; 09-10-2021, 05:51 PM.
                              9 PC LCD Monitor
                              6 LCD Flat Screen TV
                              30 Desk Top Switching Power Supply
                              10 Battery Charger Switching Power Supply for Power Tool
                              6 18v Lithium Battery Power Boards for Tool Battery Packs
                              1 XBox 360 Switching Power Supply and M Board
                              25 Servo Drives 220/460 3 Phase
                              6 De-soldering Station Switching Power Supply 1 Power Supply
                              1 Dell Mother Board
                              15 Computer Power Supply
                              1 HP Printer Supply & Control Board * lighting finished it *


                              These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                              1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                              2 Hem Saw Computer Stack Board

                              All of these had CAPs POOF
                              All of the mosfet that are taken out by bad caps

                              Comment


                                #16
                                Re: ATX PSU Tester Analyzer modification / upgrade

                                As said yes a wayward 5VSB is a concern. Not like you completely remove the regulator, need to redesign it, perhaps with a shunt regulator to protect it. Have a LDO regulator there. Shouldn't be way too hard to protect against a wayward 5VSB.

                                Comment


                                  #17
                                  Re: ATX PSU Tester Analyzer modification / upgrade

                                  Would this regulator work

                                  LP2950ACDT-5.0G
                                  9 PC LCD Monitor
                                  6 LCD Flat Screen TV
                                  30 Desk Top Switching Power Supply
                                  10 Battery Charger Switching Power Supply for Power Tool
                                  6 18v Lithium Battery Power Boards for Tool Battery Packs
                                  1 XBox 360 Switching Power Supply and M Board
                                  25 Servo Drives 220/460 3 Phase
                                  6 De-soldering Station Switching Power Supply 1 Power Supply
                                  1 Dell Mother Board
                                  15 Computer Power Supply
                                  1 HP Printer Supply & Control Board * lighting finished it *


                                  These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                  1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                  2 Hem Saw Computer Stack Board

                                  All of these had CAPs POOF
                                  All of the mosfet that are taken out by bad caps

                                  Comment


                                    #18
                                    Re: ATX PSU Tester Analyzer modification / upgrade

                                    Can I just mention guys that my internal mod actually costs less than the 9V battery, Duracell or otherwise

                                    And you can't forget to turn it off
                                    Follow me on YouTube
                                    ------------------
                                    Learn Electronics Repair
                                    https://www.youtube.com/channel/UCFX...R8UZ2vg/videos

                                    Comment


                                      #19
                                      Re: ATX PSU Tester Analyzer modification / upgrade

                                      Or would this work on the 5 standby circuit just in case the voltage has gone to hell and remove the regulator that is on the board now one note I am also going to put a switch on the power ON wire so I can control it coming ON
                                      Attached Files
                                      Last edited by sam_sam_sam; 09-11-2021, 11:15 AM.
                                      9 PC LCD Monitor
                                      6 LCD Flat Screen TV
                                      30 Desk Top Switching Power Supply
                                      10 Battery Charger Switching Power Supply for Power Tool
                                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                                      1 XBox 360 Switching Power Supply and M Board
                                      25 Servo Drives 220/460 3 Phase
                                      6 De-soldering Station Switching Power Supply 1 Power Supply
                                      1 Dell Mother Board
                                      15 Computer Power Supply
                                      1 HP Printer Supply & Control Board * lighting finished it *


                                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                      2 Hem Saw Computer Stack Board

                                      All of these had CAPs POOF
                                      All of the mosfet that are taken out by bad caps

                                      Comment


                                        #20
                                        Re: ATX PSU Tester Analyzer modification / upgrade

                                        Not sure if the TL431 is able to absorb the surge if 5VSB is considerably overvoltage... but yeah something like this, perhaps with a regular transistor as a shunt current amplifier.

                                        Comment

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