Announcement

Collapse
No announcement yet.

psu ac240as-01 dell Optiplex 7010 pc tower

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    psu ac240as-01 dell Optiplex 7010 pc tower

    I asked this question on the dell forum but got shouted down with warnings of impending death.

    I have a dell Optiplex 7010 sff tower with a dead PSU there's no action from the bypass button on the back. I've managed to pull the board out of the casing and attached a picture of it - dell-7010-psu-ac240as-01.jpg (394.4 KB).
    Power surge caused it I think. The PSU is model: ac240as-01. I'm handy with a soldering iron and I'd appreciate any advice about which component is most likely to be the culprit. Most of the time its a capacitor but there are several, none of the capacitors look bloated or out of the ordinary. To the experienced repairer it's usually a particular capacitor. I can't see a fuse anywhere. Thanks for any help.
    Attached Files
    Last edited by neuronetv@gmail.com; 05-05-2018, 12:19 PM.

    #2
    Re: psu ac240as-01 dell Optiplex 7010 pc tower

    Welcome to the forum

    Is it possible for you to tell me what the part numbers of IC chip

    M6 and M101

    M2, M8, M9, and M21 are they all the same part number and what is the part number

    Also could you please take a photo of the bottom of the board

    What value of the caps on this board (UF) value and voltages
    Last edited by sam_sam_sam; 05-05-2018, 02:11 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


      #3
      Re: psu ac240as-01 dell Optiplex 7010 pc tower

      more pcb pictures please.

      Comment


        #4
        Re: psu ac240as-01 dell Optiplex 7010 pc tower

        Originally posted by neuronetv@gmail.com View Post
        Most of the time its a capacitor but there are several, none of the capacitors look bloated or out of the ordinary. To the experienced repairer it's usually a particular capacitor. I can't see a fuse anywhere. Thanks for any help.
        Not always does a cap need to pop it top to be bad it can also pop the bottom of the cap or not at for it to bad

        I would look for caps under 100uf and replace them but you really need a ESR meter to really check them the right 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


          #5
          Re: psu ac240as-01 dell Optiplex 7010 pc tower

          thankyou for the responses here. Attached are pics showing the chips and board underside. Here are the caps I can see:
          c112 25v 47uf
          c34 50v 100uf
          c39 can't see (v small cap)
          c37 10v 2200uf
          c496 25v 47uf
          c61 10v can't see f
          Attached Files

          Comment


            #6
            Re: psu ac240as-01 dell Optiplex 7010 pc tower

            No idea what the "Bypass button on the back" is...., but, have you checked the obvious: do you have 5vSB rail at all?
            "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
            -David VanHorn

            Comment


              #7
              Re: psu ac240as-01 dell Optiplex 7010 pc tower

              the button is PS-ON
              i'm still waiting for pcb foto's because it looks similar to the notorious model that blows itself to hell because of an under-rated ceramic snubber cap.

              Comment


                #8
                Re: psu ac240as-01 dell Optiplex 7010 pc tower

                Check and see if your main filtering caps build up voltage because if it does not it could be these two IC chip might be your problem



                https://cdn.badcaps-static.com/pdfs/...c907c22d05.pdf

                What are the part numbers of the IC chip on the heat sink
                This might be a pain in the A** but could you try and remove the heat sinks and take another photo of the top of the board
                Last edited by sam_sam_sam; 05-06-2018, 06:07 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


                  #9
                  Re: psu ac240as-01 dell Optiplex 7010 pc tower

                  Hello guys, new here, I see the post pretty old , but can you please tell me the value in ohms of the resistor that I encircled in the photo, I have an identical PSU on my bench now that is not working because of that resistor being burnt completely and can't tell the values.

                  Thank you in advance!
                  Attached Files

                  Comment


                    #10
                    Re: psu ac240as-01 dell Optiplex 7010 pc tower

                    Originally posted by Ndabu View Post
                    Hello guys, new here, I see the post pretty old , but can you please tell me the value in ohms of the resistor that I encircled in the photo, I have an identical PSU on my bench now that is not working because of that resistor being burnt completely and can't tell the values.

                    Thank you in advance!
                    5 Band resistor
                    BLUE RED WHITE GOLD GREEN
                    63 Ω ?! If my eyes got the right colors
                    Attached Files

                    Comment


                      #11
                      Re: psu ac240as-01 dell Optiplex 7010 pc tower

                      Hello everyone, in my case the Toshiba K3878 is shorted, also the C6 capacitor is broken and the C10 has a crack and should also be changed. The K3878 I've already ordered, but I'm not shure with this C6/C10 capacitors. Does anybody know which capacitors/values I should use? Thanks for any help ;-)
                      Attached Files

                      Comment


                        #12
                        Re: psu ac240as-01 dell Optiplex 7010 pc tower

                        post a track picture so we can see where the caps are connected pls.

                        Comment


                          #13
                          Re: psu ac240as-01 dell Optiplex 7010 pc tower

                          Thanks for the quick answer!
                          Yellow cycle on first foto: C6, C10 caps
                          Red Cycle: the shorted mosfet Toshiba K3878
                          Attached Files
                          Last edited by matser; 10-24-2022, 11:02 AM.

                          Comment


                            #14
                            Re: psu ac240as-01 dell Optiplex 7010 pc tower

                            try using a single 680pF 2KV cap instead of c6 and c10

                            Comment


                              #15
                              Re: psu ac240as-01 dell Optiplex 7010 pc tower

                              Thanks stj! One more question. I do have the following caps from another PC PSU at home. Measuring shows this data:
                              103: ~11-12nF
                              104: ~100nF
                              101/1KV: ~0,1nF
                              151/1KV: ~0,5nF
                              102/1KV: ~1nF
                              103/1KV: ~10nF

                              I don't know how much V the 103/104 caps have, but may I also try 101/1KV in combination with 151/1KV, or the 102/1KV alone, or is it dangerous because of the need of 2KV?
                              Attached Files

                              Comment


                                #16
                                Re: psu ac240as-01 dell Optiplex 7010 pc tower

                                1KV will fail - like before
                                that psu and a couple of similar ones have this problem - a 1KV cap cant handle the current.
                                2KV caps a physically larger and can disipate the heat.

                                btw, your 151/1kv is bad.
                                151 - 15 and one 0 - so it should read 150pF

                                Comment


                                  #17
                                  Re: psu ac240as-01 dell Optiplex 7010 pc tower

                                  Thanks for your help stj, in this case I will order also a 2KV cap.

                                  Comment


                                    #18
                                    Re: psu ac240as-01 dell Optiplex 7010 pc tower

                                    The caps arrived today, unfortunately I'm still waiting for the mosfet. I have more of this Dell 7010 optiplex SSF, so I opened up a working PSU and C6 and C10 also have a crack, but the PC was running normal?! I changed both caps to a new 2KV/680pf cap, to be on the save side. Maybe the mosfet died because of the broken caps. On a third one the caps seemed to be ok and it looks like they are labeled R 331K 1KV (very hard to see, I tried to take a foto, but it doesn't work), I changed them also (got more of this 2KV caps. The good PSUs are still working after I changed the caps ;-)

                                    I'm not an electronics engineer so it is a little bit strange for me that meassuring between the 2 holes of C6 on the board are showing a short (of course also between the two poles of C10). This is the same on the working PSUs and on the faulty one where I have taken away the shorted mosfet.

                                    As soon as the new mosfet is soldered in I'll tell you the result ;-)

                                    Comment


                                      #19
                                      Re: psu ac240as-01 dell Optiplex 7010 pc tower

                                      you need to check all the resistors in the area, when the fet blows it can take other stuff with it.

                                      Comment


                                        #20
                                        Re: psu ac240as-01 dell Optiplex 7010 pc tower

                                        I'm a litte bit confused now. Meassuring the restistors shows the following:
                                        R4 and R14 shorted (on faulty as on working PSU!)
                                        R46: 5 Ω
                                        R52: 100 Ω
                                        R4 should have 63 Ω, R14 not shure but I think ~21 Ω.

                                        Without R4, R14 and R46 connected, C6 (C10) is still shorted. I found another short with the near transformer (again also the working PSU shows the same short). Near diodes and caps seemed to be ok.

                                        Now I'm wondering how could the second PC work normaly with the same shorts in the working PSU?! The only difference I found until now was the shorted mosfet.
                                        Attached Files

                                        Comment

                                        Working...
                                        X