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    MSI K9N6SGM-V question ?

    Guys,

    I got motherboard with no display,
    And I got short on the capacitor shown in the photo...
    but when I take the capacitor out...
    The short is still there...

    Where can it be do you reckon ?

    Thanks
    Attached Files

    #2
    Re: MSI K9N6SGM-V question ?

    can it be a shorted mosfet ?

    Comment


      #3
      Re: MSI K9N6SGM-V question ?

      P75n02
      Attached Files

      Comment


        #4
        Re: MSI K9N6SGM-V question ?

        Can I replace P75N02 with VNB20N07 ??

        Comment


          #5
          Re: MSI K9N6SGM-V question ?

          Anyone knows where can I find Vcc for CPU south bridge and RAM

          Comment


            #6
            Re: MSI K9N6SGM-V question ?

            Originally posted by bianchi77 View Post
            I got motherboard with no display,
            And I got short on the capacitor shown in the photo...
            but when I take the capacitor out...
            The short is still there...

            Where can it be do you reckon ?
            Put back all of the capacitors you took out, turn ON the motherboard, and measure the voltage you see across them.
            DO NOT RUN THE BOARD WITH CAPACITORS REMOVED!

            Originally posted by bianchi77
            can it be a shorted mosfet ?
            No. If the motherboard turns ON with no display, then you do NOT have a shorted MOSFET.
            A shorted MOSFET will typically cause the power supply to crowbar and latch into protection mode (usually, you will see the PC fans spin for a second and then stop).
            Last edited by momaka; 08-10-2016, 12:03 AM.

            Comment


              #7
              Re: MSI K9N6SGM-V question ?

              What voltage value should I see in each capacitors?

              Comment


                #8
                Re: MSI K9N6SGM-V question ?

                CPU Fan is spinning perfectly when I push on PS_ON....
                Is it possible that the BIOS (firmware ) corrupted ? how can I upload new firmware ?

                Comment


                  #9
                  Re: MSI K9N6SGM-V question ?

                  The flash is 25X40VSIG, it's 512Kbytes SPI flash ....anyone has uploaded to this chip before ?

                  Comment


                    #10
                    Re: MSI K9N6SGM-V question ?

                    this one :
                    http://www.datasheetlib.com/datashee.../download.html

                    Comment


                      #11
                      Re: MSI K9N6SGM-V question ?

                      https://www.msi.com/Motherboard/supp...html#down-bios

                      Comment


                        #12
                        Re: MSI K9N6SGM-V question ?

                        Can I upload the bios file from MSI straight away to the chip without flash utility from Ami? I can unsoldered it and reflashing..

                        Comment


                          #13
                          Re: MSI K9N6SGM-V question ?

                          Some measurement I got on transistor
                          Q12 is unsoldered temporarily

                          PWM = ISL6566....is it possible if my PWM chip malfunction ?
                          Attached Files

                          Comment


                            #14
                            Re: MSI K9N6SGM-V question ?

                            in normal motherboard, I can see 1.2V on CPU side FET....is it another bad capacitor case here ? but I can't see the caps is broken...??

                            Comment


                              #15
                              Re: MSI K9N6SGM-V question ?

                              Originally posted by bianchi77 View Post
                              Some measurement I got on transistor
                              Q12 is unsoldered temporarily
                              I'm glad you posted that list with the voltages. Good info to help us help you.

                              Based on that...
                              Looks like Q11 and Q12 are for the RAM buck converter, producing RAM Vdd/Vddq voltage (which is typically 1.8 to 2 Volts for DDR2 memory). So the pair Q11 and Q12 are OKAY.

                              Next on that list: Q20. Looks like this MOSFET takes power from the DDR2 supply (RAM Vdd) and produces 1.5V on its Source. Not sure what that 1.5V rail is for, but probably a secondary Northbridge supply. Either way, 1.5V is a common voltage, so I think this is OKAY as well.

                              Then it looks like Q34 takes that 1.5V supply (via Drain) and further reduces it down to 1.2V (output from Source pin). 1.2 V is a very common voltage for Northbridge on AMD motherboards from the 939 and AM2 era. So again, I think this is OKAY.

                              Finally, MOSFETS Q15, Q14, Q10, Q9, Q7, Q3 near the CPU. These produce CPU V_core (a.k.a. CPU Vcc). For three of these MOSFETs (not sure which ones), you should have 12V on their Drain and CPU V_core on their Source (1.1 to 1.4 Volts). And for the other three that don't, they will have their Source pin connected to ground (your multimeter should show 2 Ohms or less to ground).

                              Now here is what I see wrong: from these MOSFETs near the CPU above, you don't have 12V on their Drains on any of them. When you were testing the motherboard, did you connect the 4-pin 12V CPU power connector? I know this seems like a stupid question, but those measurements certainly indicate that perhaps you forgot to.

                              Originally posted by bianchi77 View Post
                              is it another bad capacitor case here ? but I can't see the caps is broken...??
                              Capacitors don't have to be bulged to be bad.

                              I see two blue Teapo capacitors (SZ series?) near below the Northbridge on this picture:
                              https://www.badcaps.net/forum/attach...4&d=1470738633
                              If they are Teapo indeed, you need to replace them. Teapo on a motherboard is teapo-cally not a good idea .

                              As for the capacitors around the CPU, those look like Panasonic (Matsushita) with a "T" vent. Perhaps FL series. Can you confirm?

                              Lastly, the capacitors you removed seen in this picture:
                              https://www.badcaps.net/forum/attach...4&d=1470738633
                              What brand and series are they?

                              Originally posted by bianchi77 View Post
                              PWM = ISL6566....is it possible if my PWM chip malfunction ?
                              Maybe. Maybe not.
                              Check the above items I mentioned and report back.

                              Also, what brand power supply are you using?
                              And any history on the motherboard? Did you get it working or non-working? If the former, when did the problems appear?

                              The more information we have, the easier for us to help you.

                              Originally posted by bianchi77 View Post
                              Is it possible that the BIOS (firmware ) corrupted ? how can I upload new firmware ?
                              Possible, yes. But I find it unlikely.
                              Last edited by momaka; 08-12-2016, 04:46 PM.

                              Comment


                                #16
                                Re: MSI K9N6SGM-V question ?

                                Now it's doing the job until boot to Linux....but after few seconds...turned off...
                                I patch Q12 temporaly with 4N60....looks like it doesn't like it...because switching frequency I reckon...because 4N60 got heat pretty quickly....(high voltage but lower switching turn on and off, read from datasheet )

                                I've replaced 2 Caps near PWM....I reckon that's CPU Vcore supply...
                                I tested off the board, the old one, the resistance eqivalent is not stable...
                                below 1K ohm...not good....I replaced them with 2 panasonics 1800 uF/16...

                                I've been waiting for P75N02 ( the original FET ) to arrive....probably another 3 weeks...
                                anyway....why was it so difficult to unsoldered P75N02 off the board, looked like the melting point of the board solder was abit higher....
                                I used my hot gun for SMD doing it...

                                Any comments ? Ok I'll have a look on their caps

                                Comment


                                  #17
                                  Re: MSI K9N6SGM-V question ?

                                  Caps photos
                                  Attached Files

                                  Comment


                                    #18
                                    Re: MSI K9N6SGM-V question ?

                                    do you mean those 470uF/16V under the northbridge ?

                                    Comment


                                      #19
                                      Re: MSI K9N6SGM-V question ?

                                      Originally posted by bianchi77 View Post
                                      Now it's doing the job until boot to Linux....but after few seconds...turned off...
                                      I patch Q12 temporaly with 4N60....looks like it doesn't like it...because switching frequency I reckon...because 4N60 got heat pretty quickly....(high voltage but lower switching turn on and off, read from datasheet )
                                      OKAY, if you want to fix that motherboard - *STOP* and get a proper replacement MOSFET.

                                      4N60 is a 4 Amp, 600V MOSFET, whereas the P75N02 is a 75 Amp MOSFET. You used a MOSFET that has nearly 20 times lower current rating! I'm surprised the damn thing even worked. You really need to read more before doing these things or ask here, if you care about fixing the motherboard properly.

                                      Do NOT power on the motherboard until you get a proper replacement MOSFET.

                                      Originally posted by bianchi77 View Post
                                      I've been waiting for P75N02 ( the original FET ) to arrive....probably another 3 weeks...
                                      Well, you don't really need to get exactly a P75N02 replacement MOSFET. There are many other alternatives that would have likely worked okay there. In general, as long as you stay within 10% of the current rating of the original MOSFET, and the voltage rating is the same or higher of the replacement MOSFET, then things are more likely to work fine than not.

                                      Originally posted by bianchi77 View Post
                                      I've replaced 2 Caps near PWM....I reckon that's CPU Vcore supply...
                                      I tested off the board, the old one, the resistance eqivalent is not stable...
                                      below 1K ohm...not good....I replaced them with 2 panasonics 1800 uF/16...
                                      Are you talking about the green capacitors in this picture?
                                      https://www.badcaps.net/forum/attach...4&d=1471065968
                                      Those green capacitors look like Sanyo/Suncon WG or WX. If you got them from eBay, Amazon, or AliExpress, they are very likely fake (counterfeit).
                                      Second, you should NOT solder capacitors with long leads like that. The motherboard will see them as high-ESR and possibly not work properly.

                                      The original capacitors near the CPU appear to be Panasonic FL or perhaps FJ/FJS. Again, please check what you have and report back. If this is true, put those original capacitors back in - I am 99% sure they are better than those green sketchy-looking Sanyo/Suncon capacitors.

                                      Also, I apologize for criticizing your work so much. However, I am doing this so that you can learn. And if someone else reads this thread, they will have a better idea of what to do as well.

                                      Originally posted by bianchi77 View Post
                                      anyway....why was it so difficult to unsoldered P75N02 off the board, looked like the melting point of the board solder was abit higher....
                                      I used my hot gun for SMD doing it...
                                      Just about every motherboard made in the last decade used/uses lead-free solder, which as you noted, melts at a higher temperature (213°C) vs. regular 60/40 Sn-Pb solder (183°C).

                                      Be careful when removing SMD parts with hot air tools near electrolytic capacitors - the heat can kill those capacitors. Most MOSFETs, I remove with two soldering irons. It is much quicker and easier to do. But at least one of the soldering irons needs to be rated for 60 Watts or more and have a "fat" chisel/bevel tip.

                                      Originally posted by bianchi77 View Post
                                      do you mean those 470uF/16V under the northbridge ?
                                      Well I can't answer that, because I can't read the values of those caps from your pictures and I do NOT have this motherboard in front of me. I am helping you troubleshoot this completely from the picture and information you provided here.

                                      But like I said, if you look at the Northbridge (black heatsink) in this picture:
                                      https://www.badcaps.net/forum/attach...5&d=1470739111
                                      Those capacitors are directly below it. A little further below those capacitors is the audio/LAN connector.
                                      Last edited by momaka; 08-13-2016, 08:47 PM.

                                      Comment


                                        #20
                                        Re: MSI K9N6SGM-V question ?

                                        Yup, I know it's for 4A, I like to do experiment with it....and it worked
                                        I've replaced it with D450 and now it's stable...

                                        Thanks for the suggestion, yup I've done with big chissel tip and it's a lot easier...
                                        and two solders working together as a clamp is the trick I have done...

                                        Comment

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