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Toshiba A665 blown MOSFET

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    #61
    Re: Toshiba A665 blown MOSFET

    Do I still need to measure the DC current between PIN 5 Q30 and Ground?

    LOL, I meant Pin4.... mistype..
    Last edited by Rolin; 08-11-2012, 12:18 AM.

    Comment


      #62
      Re: Toshiba A665 blown MOSFET

      no, by the way, it is not pin 5 (That is Drain pin, it would have been big spark! if you do), it is pin 4 (Gate pin). You are OK, no need to do current test, too dangerous
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment


        #63
        Re: Toshiba A665 blown MOSFET

        By the way, did you find out if you get the POST when you turn on the computer?
        Never stop learning
        Basic LCD TV and Monitor troubleshooting guides.
        http://www.badcaps.net/forum/showthr...956#post305956

        Voltage Regulator (LDO) testing:
        http://www.badcaps.net/forum/showthr...999#post300999

        Inverter testing using old CFL:
        http://www.badcaps.net/forum/showthr...er+testing+cfl

        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
        http://s807.photobucket.com/user/budm/library/

        TV Factory reset codes listing:
        http://www.badcaps.net/forum/showthread.php?t=24809

        Comment


          #64
          Re: Toshiba A665 blown MOSFET

          What do you think is causing the 19V at PIN4 then?

          Yes, I do get a POST. Almost feel like leaving PIN6 lifted on Q11 and run it! Probably not a good idea, but what would happen?

          Comment


            #65
            Re: Toshiba A665 blown MOSFET

            I think the 200K is not 200K but 260K, but you already found the 47K resistor which is more important, it is the resistor at the bottom right of Q30 by pin 4 that you found, right?
            Never stop learning
            Basic LCD TV and Monitor troubleshooting guides.
            http://www.badcaps.net/forum/showthr...956#post305956

            Voltage Regulator (LDO) testing:
            http://www.badcaps.net/forum/showthr...999#post300999

            Inverter testing using old CFL:
            http://www.badcaps.net/forum/showthr...er+testing+cfl

            Tear down pictures : Hit the ">" Show Albums and stories" on the left side
            http://s807.photobucket.com/user/budm/library/

            TV Factory reset codes listing:
            http://www.badcaps.net/forum/showthread.php?t=24809

            Comment


              #66
              Re: Toshiba A665 blown MOSFET

              In the picture, It's the black component to the right of PIN4 Q30 and just below PIN3 of Q11

              If I understand correctly, I just need to replace the Q11 at this point, correct?

              It's 1:30AM, I better get to bed or I'll fall a sleep on my keyboard! I'll read your answer tomorrow...

              Good night Bud!
              Last edited by Rolin; 08-11-2012, 12:37 AM.

              Comment


                #67
                Re: Toshiba A665 blown MOSFET

                These resistors in circle, right?
                Attached Files
                Never stop learning
                Basic LCD TV and Monitor troubleshooting guides.
                http://www.badcaps.net/forum/showthr...956#post305956

                Voltage Regulator (LDO) testing:
                http://www.badcaps.net/forum/showthr...999#post300999

                Inverter testing using old CFL:
                http://www.badcaps.net/forum/showthr...er+testing+cfl

                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                http://s807.photobucket.com/user/budm/library/

                TV Factory reset codes listing:
                http://www.badcaps.net/forum/showthread.php?t=24809

                Comment


                  #68
                  Re: Toshiba A665 blown MOSFET

                  Originally posted by Rolin View Post
                  What do you think is causing the 19V at PIN4 then?

                  Yes, I do get a POST. Almost feel like leaving PIN6 lifted on Q11 and run it! Probably not a good idea, but what would happen?
                  5VS will stay on even when the laptop is off, which means a lot of things powered when they shouldn't be, and some chips might be subjected to backflow of current through their protection diodes, not good at all. In addition it'll probably

                  If they didn't care about draining 5VS quickly when turning off, they wouldn't have Q11 discharge the rail. 5V into 470 ohms means ~10mA will be going through there.

                  At best you'll have a battery that drains faster, at worse it could cause long-term damage to more sensitive parts.
                  Last edited by b700029; 08-11-2012, 04:05 AM.

                  Comment


                    #69
                    Re: Toshiba A665 blown MOSFET

                    B700029: Yea, I suspected something like that - it would cause some sort of problem. I was kind of kidding - we're this far so I'll replace Q11 once I find one - the fact it's turning on again makes it very slightly tempted to leave it alone!- but I won't.

                    Q11 is such a small chip, I doubt I'll be able to find a replacement on one of my many scrap boards laying around here, so I'll order from digikey or somewhere.

                    Bud: I attached a picture of the R410 resistor area. Below the resistor it's a blank (nothing there, just two solder points). The item to the left is what appears to be a cap.
                    Attached Files

                    Comment


                      #70
                      Re: Toshiba A665 blown MOSFET

                      That is good that it is 47K, you are safe to install new Q11. We are almost done!
                      Never stop learning
                      Basic LCD TV and Monitor troubleshooting guides.
                      http://www.badcaps.net/forum/showthr...956#post305956

                      Voltage Regulator (LDO) testing:
                      http://www.badcaps.net/forum/showthr...999#post300999

                      Inverter testing using old CFL:
                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                      http://s807.photobucket.com/user/budm/library/

                      TV Factory reset codes listing:
                      http://www.badcaps.net/forum/showthread.php?t=24809

                      Comment


                        #71
                        Re: Toshiba A665 blown MOSFET

                        The schematic shows R413 with an "@" sign after it. I think this means the component was omitted because it was deemed unnecessary.

                        Comment


                          #72
                          Re: Toshiba A665 blown MOSFET

                          Ordered the MOSFET from Digikey. Will let you know what happens after the installation.

                          Comment


                            #73
                            Re: Toshiba A665 blown MOSFET

                            Just wanted to update the forum on this one. I installed Q11 and Q30 - everything is working properly. I want to thank everyone who helped on this laptop motherboard repair. I learned a lot, and had some fun. Thank you!!

                            Comment


                              #74
                              Re: Toshiba A665 blown MOSFET

                              Thank you for letting us know the result, great job getting it fixed.
                              Never stop learning
                              Basic LCD TV and Monitor troubleshooting guides.
                              http://www.badcaps.net/forum/showthr...956#post305956

                              Voltage Regulator (LDO) testing:
                              http://www.badcaps.net/forum/showthr...999#post300999

                              Inverter testing using old CFL:
                              http://www.badcaps.net/forum/showthr...er+testing+cfl

                              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                              http://s807.photobucket.com/user/budm/library/

                              TV Factory reset codes listing:
                              http://www.badcaps.net/forum/showthread.php?t=24809

                              Comment


                                #75
                                Re: Toshiba A665 blown MOSFET

                                sir i have dead notcharging toshiba satellite l10 i repair charging ok set is on but one problem sum time graphic ok after5minut gone lcd and sistem shutdown i check board a pq40 si4922mosfet vry heat schematic page no;27 how to get this mosfet

                                Comment


                                  #76
                                  Re: Toshiba A665 blown MOSFET

                                  Originally posted by b700029 View Post
                                  A quick glance at the schematic shows that Q30 is for powering +5VS from the +5VALW rail (and possibly vice-versa, depending on how they designed the power sequencing).

                                  I suggest looking for the problem somewhere else. The weird behaviour you're seeing is just an artifact of rails being powered from backflows of voltages through other components like IC's protection diodes. I would not recommend trying to run the system in that state as they're not designed to take such large currents.

                                  P.S. in case you don't know already, MOSFETs are highly static-sensitive. You might've killed or damaged them if you weren't being cautious with ESD.
                                  How do I download these schematics. It keeps redirecting me to a page requiring authorization.

                                  Basically I need to know the part in slot PQ7. It burned out.

                                  Comment


                                    #77
                                    Re: Toshiba A665 blown MOSFET

                                    Duf Duf -Please can you update your profile with state.
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment


                                      #78
                                      Re: Toshiba A665 blown MOSFET

                                      Very educate, i can learn from this case, very interested.
                                      Here you are duf-duf
                                      Attached Files

                                      Comment


                                        #79
                                        Re: Toshiba A665 blown MOSFET

                                        Originally posted by degutji View Post
                                        Very educate, i can learn from this case, very interested.
                                        Here you are duf-duf
                                        WOW thanks folks for the speedy response. I see my part is on page 37 upper left hand, next to the Vin. Looks like a DMOS device.

                                        Now where do I order such part? Digi-key? I assume that AO4435_SOB, is A-oh not a-zero. And SOB?? OK noob question, what does SOB stand for?? I know what I think it stands for....

                                        Comment


                                          #80
                                          Re: Toshiba A665 blown MOSFET

                                          Well this is what I ordered, hope it's right. No wonder these things blow out, the power cord comes in at 19 VDC and the chip is set for 20 V max.

                                          http://www.digikey.com/scripts/DkSea...4435&WT.srch=1

                                          Comment

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