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Sony Vaio VPC-SB26FG cannot power on

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    #41
    Re: Sony Vaio VPC-SB26FG cannot power on

    Originally posted by orientalsniper
    Hello, when you were repairing a MBX-458, why did you apply current to the cap in red box? And not the others?
    Hi there!

    The cap that is in the red box was faulty. But when I applied current to GREEN points, I did not know this yet.

    The reason I applied current to these (GREEN) spots is that these are main GROUND and VIN (+) in points on this board. And when you apply current to the shorted cirquit, it starts to dissipate heat. The component that gets warm is most likely to be defective.

    In my case it was the capacitor outline in red.

    Comment


      #42
      Re: Sony Vaio VPC-SB26FG cannot power on

      Originally posted by vaiohustler View Post
      could guide me a little to find the faulty component
      Why do you think you would get anything more than 0.01V on these pads without battery connected and with KBC (keyboard controller) disconnected (it is located on the MAIN board, MBX-238, and rules the charging process)?

      The points you measure voltages at are battery "+" and "-" terminals, and there has to be no voltage (or close to none) without battery.

      The point we discuss in this thread is that there is a short cirquit on the MAIN board (MBX-238) that causes CNX-458 to SHUT OFF the output if it detects overcurrent on any of the outgoing cirquits.

      So, please measure the resistance between the green points on my photo. If it is close to zero, then apply regulated current supply to these points and check what elements do heat up.

      Is there any reaction on the "power on" button?
      Last edited by michaeleangelo; 12-20-2013, 08:42 AM.

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        #43
        Re: Sony Vaio VPC-SB26FG cannot power on

        Originally posted by michaeleangelo View Post
        Of course, in your case this can be ANY other cap or semiconductor, but the main method is the same: apply safe voltage (lower than the intended voltage for the shorted circuit) to the shorted circuit and slowly raise the current while controlling the temperature of the board (with your hands or using any pyrometer).

        Good luck, colleagues, and successful repairs to you all! :-)
        Thanks a lot! For me it was the one next to it.
        It took me a while to find it, because it didn't really get hot, even with 6A. But as the cable already got warm, I simply tried first your broken one and then the one where I put current on --> Got it
        It's back to life, Thank you man!

        Comment


          #44
          Re: Sony Vaio VPC-SB26FG cannot power on

          Originally posted by datom View Post
          Thanks a lot! For me it was the one next to it.
          It took me a while to find it, because it didn't really get hot, even with 6A. But as the cable already got warm, I simply tried first your broken one and then the one where I put current on --> Got it
          It's back to life, Thank you man!
          how could you solve this prob.. ? Thanks for you answer right now.. !

          Comment


            #45
            Re: Sony Vaio VPC-SB26FG cannot power on

            Originally posted by chat007 View Post
            I swapped the motherboard and it's now working . Thanks for pointing out the problem is on the MB. When you are swapping the board, make sure the dip switches match.
            swapped? change your mob with new one?

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              #46
              Re: Sony Vaio VPC-SB26FG cannot power on

              hi thanks a lot for your help
              I have a sony vaio vpcsb1s1e
              and it's dead not working at all
              when i saw your reply about changing capacitor I found two capacitor with 0 ahm
              "the capacitor in the red box and the one below it" and I replace them but it still dead so I need to ask and make my self sure about the capacitor if the 10uf 25v or not
              and I need help for the next step what can I check or what I missed
              is the bios need to charge again from usb port

              Comment


                #47
                Re: Sony Vaio VPC-SB26FG cannot power on

                hi thanks a lot for your help
                I have a sony vaio vpcsb1s1e
                and it's dead not working at all
                when i saw your reply about changing capacitor I found two capacitor with 0 ahm
                "the capacitor in the red box and the one below it" and I replace them but it still dead so I need to ask and make my self sure about the capacitor if the 10uf 25v or not
                and I need help for the next step what can I check or what I missed
                is the bios need to charge again from usb port
                Attached Files

                Comment


                  #48
                  Re: Sony Vaio VPC-SB26FG cannot power on

                  hi there. Check also the caps next to the one you have changed. Also check in the small psu board under the stickers of the connectors for tiny fuses.

                  Comment


                    #49
                    Re: Sony Vaio VPC-SB26FG cannot power on

                    Originally posted by oxgan View Post
                    how could you solve this prob.. ? Thanks for you answer right now.. !
                    I simply changed all of the 3 caps (10uF, 25V) to make sure it will last longer, maybe they didn't use 25V caps
                    For me there was nothing else to do

                    Comment


                      #50
                      Re: Sony Vaio VPC-SB26FG cannot power on

                      Are the values written on the image correct ???
                      What are the values of capacitors located by the question marks???
                      Is it possible to give me a photo showing the names of the electronic items found on the main board to compare it with the existing maintenance manual???
                      sorry for my questions but I am run out of hope to maintenance my laptop
                      Attached Files
                      Last edited by osama31; 04-09-2014, 04:42 AM.

                      Comment


                        #51
                        Re: Sony Vaio VPC-SB26FG cannot power on

                        I've had a VPCCSA with that model motherboard recently, not powering on.

                        Replaced the cluster of three caps marked in the picture and got it starting up again.

                        Comment


                          #52
                          Re: Sony Vaio VPC-SB26FG cannot power on

                          Originally posted by michaeleangelo View Post
                          The capacitor in a RED rectangle became hot immediately. So, it was shorted to the ground. After I have removed it, all the shorts with black (6-pin and 10-pin) connectors went away.
                          Same problem thx for sharing, laptop works again.

                          Comment


                            #53
                            Re: Sony Vaio VPC-SB26FG cannot power on

                            Thanks for all the people that has posted solutions and things to try. I have tried some of them and i have a different problem then most so i want to get your input

                            I have posted a picture

                            The Red Square (where everyone else is having issues) seems to be good with a 0.86 reading.

                            The Green Square i get a .006 reading and the purple square i get 0.001 0.000.

                            Now i tried what michaeleangelo posted with the power supply, one lead on ground and the other on the positive side of the cap in the green square. I set the power supply to 1.5 or so volts and about 2.0 - 2.2 A and the only thing that warmed up was the south-bridge (Not hot but warm)

                            Now, the south bridge is right on the other side of the purple set of boxes where i am getting 0.000.

                            Is this a bad south bridge??? any other suggestions on things to try??

                            Thanks
                            Michael
                            Attached Files

                            Comment


                              #54
                              Re: Sony Vaio VPC-SB26FG cannot power on

                              Hi, my vpc-sb does not charge battery , i checked the cnx-458 daughter board and found that IC w_pu1 is rusted and the resistance around it are also rusted. could anyone help and let me know the values of the following resistances
                              w_pr31, w_pr46, w_pr47, w_pr17.
                              Thanks
                              Sukhvinder

                              Comment


                                #55
                                Re: Sony Vaio VPC-SB26FG cannot power on

                                w_pu1= 74HCT253D

                                w_pr31= 100K
                                w_pr46= 100K
                                w_pr47= 100K
                                w_pr17= 300K
                                Size 0402
                                Last edited by datom; 10-26-2014, 05:50 AM.

                                Comment


                                  #56
                                  Re: Sony Vaio VPC-SB26FG cannot power on

                                  Hi, I have 2 or 3 of the VPCSB laptops with these MBX-237 Motherboards, 2 x i5's and 1 x i7. Does anyone in UK offer a repair service on this board, i'd like to get them repaired if possible. I have no experience of soldering. I normally just swap out laptop components to get laptops working again so left with these faulty ones. Preferably want to get the i7 repaired.

                                  Thanks
                                  Ranjit

                                  Comment


                                    #57
                                    Re: Sony Vaio VPC-SB26FG cannot power on

                                    ive have the same problem my DCBATOUT as labeled in the schematics is shorted to ground,i cant trace the shorted one cause i have no label in main board thats what makes it difficult to trace,

                                    Comment


                                      #58
                                      Re: Sony Vaio VPC-SB26FG cannot power on

                                      Originally posted by mangtomas View Post
                                      ive have the same problem my DCBATOUT as labeled in the schematics is shorted to ground,i cant trace the shorted one cause i have no label in main board thats what makes it difficult to trace,
                                      We require the boardview for this schematic.

                                      I have the software which I can upload here, but not the boardview file for the MBX237

                                      Comment


                                        #59
                                        Re: Sony Vaio VPC-SB26FG cannot power on

                                        Hello Everyone, I have similar problem with my Sony did not power up. The motherboard is same mbx-237. When connect the power only battery charging, when press the power button the battery led dimmed ); and nothing. Any ideas?
                                        Thanks

                                        Comment


                                          #60
                                          Re: Sony Vaio VPC-SB26FG cannot power on

                                          cook its,its hard to troubleshoot if the mb has no label

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