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LG 31MU97 no power

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    LG 31MU97 no power

    Hi there.
    I got this pretty nice monitor a couple of years ago and it worked fine until the day it didn't. No power surges, just shut down while I was using it with my computer, and while attached to a APC SmartUPS. After some research it turns out that this LG 31MU97 does tend to die after a year and half of use (just read massive number of reports of such on Amazon). One company in US actually developed a service specifically for this model to fix the issue, and, it seems, it all revolves around replacing just one part on the mainboard - EEPROM IC205 which regulates power input.
    http://www.coppelltvrepair.com/p/148...replacement-ic
    They sell the chip itself or the service to apparently replace it on the board.

    Being outside the US, I can't really avail myself to their service but I found an alternate solution on the internet which seems to have worked but I can't find any logic behind it and decided to ask people in the know whether or not that solution is worth trying. It is posted in a blog here:
    https://integer13.wordpress.com/2018...-piece-of-sht/
    Basically it involves shorting pins of the same EEPROM chip to coax it into working again. This seems to be rather dangerous and yet it the only feasible solution available to me. I would appreciate however if someone could explain the logic behind this and alleviate some of my concerns with this operation.

    #2
    Re: LG 31MU97 no power

    This is the datasheet for that chip.



    I haven't read it in detail to find out what the fix is supposed to do, but if you're feeling squeamish about applying power to the pin, just take the power from the VCC pin on the chip instead, it should accomplish the same thing.

    I think there is something about the chip going into standby mode if it encounters errant signal noise that happens during power on/off. Keeping SCLK or CS# pin high during startup is supposed to reset that state, or something. Not sure. But if you only connect VCC to the pins, you really can't hurt the chip.

    Comment


      #3
      Re: LG 31MU97 no power

      I had this issue and came across this blog that helped fix it with a multimeter and an hour of my time. https://www.ifixit.com/Answers/View/...power+board+OK.

      Hope this will help others too.

      Comment


        #4
        Re: LG 31MU97 no power

        I had the same issue not turning on. I downloaded the free service PDF and checked the power suppies (8 i think) one had a short to ground this had taken out IC700 MP2315GJ buck chip. I suspected a bad cap but this power line went to H5PS1G63KFR 1gig DDR2 ram chip and this had the short to ground.

        I am waiting for chips then hopefully i will have my monitor back in service.
        If your fault is the bios chip IC205 available on ebay and easy to flash. The trick with applying a voltage to the chip was done through a multimeter off the 19v line. I would try with 3.3v from that ic this may take lts of attempts as i seem to remember it must be done on the rising edge of the clk cycle.

        Comment


          #5
          Re: LG 31MU97 no power

          Have you at least checked the power supply to see if the +19 volts is there?

          Comment


            #6
            Re: LG 31MU97 no power

            bin ok
            Attached Files

            Comment


              #7
              Re: LG 31MU97 no power

              Originally posted by especim3n View Post
              bin ok
              Thank you Very much, i fixed my screen with this firmware

              Comment


                #8
                Re: LG 31MU97 no power

                Me too, i fix monitor with this dump on mxic.Thanks.

                Comment


                  #9
                  Re: LG 31MU97 no power

                  I can confirm, it work with dump file. Thanks for it.

                  Comment


                    #10
                    Re: LG 31MU97 no power

                    I can also confirm that dump works, but I have a 31MU97Z monitor with thunderbolt and that bin is for the no thunderbolt version. I have currently thunderbolt disabled.
                    Can someone find the correct bin file for thunderbolt version?

                    Comment


                      #11
                      Re: LG 31MU97 no power

                      Originally posted by especim3n View Post
                      bin ok
                      Thanks, it works.

                      Comment


                        #12
                        Re: LG 31MU97 no power

                        Can someone get the file to the thunderbolt version?
                        31MU97Z
                        The file here works but you will have thunderbolt disabled

                        Comment


                          #13
                          Re: LG 31MU97 no power

                          Originally posted by especim3n View Post
                          bin ok
                          big THANK man. It fixed 'no power'

                          Comment

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