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ASRock 775 i65G

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    ASRock 775 i65G

    Got this MB dirt cheap, it has a burnt n-channel mosfet APM2030N.
    The board starts up with no display, just the fan spinning.
    Googled Apm2030n and found lots of ASRock MB with the same burnt mosfet.
    Some of them were fixed, some not.

    I found a seller on ebay, but the price is 7£ with postage, bit of a ripoff.
    So I need to find a replacement, is there any website you guys use where you can type in voltages and package type and get a similar spec. part.

    Thanks
    Attached Files

    #2
    Re: ASRock 775 i65G *Fixed

    Started to pull of Q27, just to find the cooper trace has bean lifted from the mb.
    Anyway I decided to play with the board, and swapped the apm2030n with apm2014n I found on a scrap mb. After soldering it (somehow), still no display.

    So I decided to replace the cap. CE37 which is close to the mosfet.
    Now I get a couple of random beeps, but still no display.
    Cleared the CMOS, still the same.
    After an close inspection it looked like RN48 was also burnt, I took it off and bridged the connection, and the MB is alive

    The question still remains, what website do you use to find replacement parts?

    Comment


      #3
      Re: ASRock 775 i65G

      international rectifier has a lookup system on the website to find alternative parts.

      btw,
      i'v fixed a few mobo's with shorted fets - every time i had to relpace the fet-driver chip too.
      usually something starting with "hip"
      Last edited by stj; 04-30-2014, 09:48 AM.

      Comment


        #4
        Re: ASRock 775 i65G

        Originally posted by stj View Post
        international rectifier has a lookup system on the website to find alternative parts.

        btw,
        i'v fixed a few mobo's with shorted fets - every time i had to relpace the fet-driver chip too.
        usually something starting with "hip"
        Hi,Im a newbie in this forum. I know that this is an old post & I don't want to bother you but I have the same problem & I have a question for you.If it is not a problem I would appreciate a lot if you help me.I'm going to change the APM2030n on my mobo, & now I reading your post & I would like to know which is the fet-driver chip.If I upload a pic of my mobo would you help me by marking the fet-driver chip on the pic pls?By the way its my first time trying to do this work,its for my own.Thanks.
        Attached Files

        Comment


          #5
          Re: ASRock 775 i65G

          Originally posted by 3d0 View Post
          is there any website you guys use where you can type in voltages and package type and get a similar spec. part.
          I use Digikey.com or Mouser.com. Even if Digikey doesn't ship to your country, it's still a useful website for the exact purpose you mentioned - you select various specs of the part you are looking for and you get results of what is available on the market today.

          Originally posted by 3d0 View Post
          Googled Apm2030n and found lots of ASRock MB with the same burnt mosfet.
          Looks like that MOSFET is for the RAM Vdd/Vddq voltages (i.e. 2.5V for DDR and 1.8V for DDR2). Probably stepped down from the PSU 3.3 V rail in a linear fashion, hence all the heat discoloration on the board. Both ASUS and AsRock are notorious for having hot-running MOSFETs on the RAM on boards made during that era (socket 754, 939, AM2, and 775), since AsRock boards were designed and made by ASUS back then. I don't know if that is still true for new AsRock boards today.

          Either way, it would be wise to put some kind of a heatsink on your new MOSFET. Regardless of what MOSFET you have there, it will still likely discolor the board and eventually burn out. This is because when the MOSFET is used as a linear regulator, it dissipates the excess voltage drop times current used as heat.

          The most effective way to heatsink that MOSFET is to solder a thick, long, solid piece of copper wire to the MOSFET's Drain tab and have the wire point up from the board. If you have thin copper or steel sheets and solder those to the wire, you will improve the heatsink even more. Of course, if you do make a heatsink like that, make sure it doesn't come in contact with any other metal parts, since it will be at the same potential as the Drain of the MOSFET (whatever that may be, though I suspect 3.3V rail from the PSU).

          Originally posted by stj View Post
          i'v fixed a few mobo's with shorted fets - every time i had to relpace the fet-driver chip too.
          I've had to replace MOSFETs too, but whatever was driving the MOSFET wasn't always damaged. Also, it appears the O/P's board uses a linear regulator, so most likely that MOSFET is driven either by an op-amp/comparator or 431 shunt regulator.

          I do agree with you, though - it's always a good idea to check whatever is driving the burned MOSFET, because it could indeed be damaged.
          Last edited by momaka; 05-07-2016, 12:45 PM.

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