Asus VW246H will not power on

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  • UKRobster
    Member
    • Nov 2013
    • 22
    • UK

    #41
    Re: Asus VW246H will not power on

    The other caps on the board are : 470uF 35v & 220uF 25v
    I have found these, could anyone confirm they are correct?

    470uF
    220uF

    They are the same make and series as the one I ordered for the start up cap.

    Comment

    • selldoor
      Slow Learner
      • Dec 2010
      • 7870

      #42
      Re: Asus VW246H will not power on

      I would say a cold joint on small caps is not common (apart from the ones I solder )
      They are usually on larger components that get hot and usually high voltage .On some sets we recommend re flowing the main transformer , inverter transformers , high voltage blue caps, inductors (coils) as a matter of course.
      Look on google for pictures of cold joints so you know what to look for and perhaps try to
      narrow the search down to a board then funnel the heat with a card tube to try and pin it down to a section. Takes some time but perhaps easier than resoldering and replacing caps at random. Those caps are ok PROVIDING they are not too wide to fit.
      I havent looked but panasonic FR or FM would also be good if they are a little cheaper.

      Once again if you can try heating just some of the caps to see which ones make a difference to it coming on or not.

      Another possibility is using freeze spray to cool certain areas while the set is on and see if it goes off ( more use for bad joints)
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment

      • UKRobster
        Member
        • Nov 2013
        • 22
        • UK

        #43
        Re: Asus VW246H will not power on

        I have had a look at some cold solder joints. Will inspect the board with a magnifying glass.
        The 470uF caps may be too wide. Will check that too.

        Thanks for the other advise I think I will try to narrow down which section of the board the issue appears to be in!

        Comment

        • Davi.p
          Hobbist Tech
          • Sep 2009
          • 4282
          • Italy - Milan

          #44
          Re: Asus VW246H will not power on

          I would point attention first on the primary side solder joints then the rest, if you don't find anything cracked you could try to heat a bit the thermal resistor with solder iron then power on and see.. it is near the 220vac input connector, if nothing changes change low voltage caps. If you have desire you can first try to power up the monitor with heating and test which voltage you have on the middle pin of the 2 double diodes, since you have 1 only primary output voltage, if is a 12v then you can desolder jumper JW17 and connect an external 12v for test and see what happens.. or at least try to give power to monitor without heating and see if the main voltage on that diodes is present.
          Last edited by Davi.p; 01-16-2014, 01:32 PM.

          Comment

          • UKRobster
            Member
            • Nov 2013
            • 22
            • UK

            #45
            Re: Asus VW246H will not power on

            I have inspected the underside of the board, and have found the attached images.
            I have only the research I did on Google to try to identify a 'cold solder joint'.
            The first picture shows the component attached, which looks like two items attached either end of a heatsink.
            Are these the diodes Davi.p mentions?

            Then I have tried to get the best pictures I can of the underside.
            I know they are not the clearest images, but do they look like cold solder joints?
            Attached Files

            Comment

            • Davi.p
              Hobbist Tech
              • Sep 2009
              • 4282
              • Italy - Milan

              #46
              Re: Asus VW246H will not power on

              "Are these the diodes Davi.p mentions?" Yes. I don't see cold joints.

              Comment

              • Edj628
                New Member
                • May 2014
                • 2
                • US

                #47
                Re: Asus VW246H will not power on

                Hey gentleman, another newbie here. I have an Asus vw246h as well, and I've discovered that my ccfl tubes were broken up top. I decided to buy a set of LED strips with an inverter board from ebay, and I honestly have no idea how to install it. I do know how to solder. I was wondering if you guys could be of assistance?

                Here's in for for the led's and board I purchased. I tried following the instructions on the website, but I'm not very good at deciphering broken English .

                www.creatall.com

                Comment

                • tom7688
                  New Member
                  • Jun 2018
                  • 1
                  • USA

                  #48
                  Re: Asus VW246H will not power on

                  Hoping someone from the original thread can reply about how they fix it. Here we are years later, I have the same monitor and the same problem! Hoping someone was successful in repairing and can share what they did.

                  Comment

                  • Hammer034
                    New Member
                    • Jul 2019
                    • 6
                    • usa

                    #49
                    Re: Asus VW246H will not power on

                    Hi all.
                    Long time lurker first time poster.
                    Have same monitor as above with same problem.
                    Unplugged and will not power on again.Monitor did this back in july but after sitting for a week it worked again until now when i had to kill breakers to replace outlet.
                    When I plug it in, power light will flash once and thats it. if i unplug and replug right away it will not flash. If I wait a minute to replug it will flash again.
                    I replaced all caps with new panasonics even the main big cap and it still does the same thing.
                    I have 157 volts on big cap (Im in the USA).
                    I have checked all diodes and resistors(still in circuit, ya i know) and they appear ok.
                    I have not pulled and checked the mosfet(Q601) yet.
                    On the 12 pin connector I have some strange voltages when checking to ground lug on board.
                    Pin numbers and voltages below.
                    1 45v ac
                    2 45v ac
                    3 unused
                    4 unused
                    5 45v ac
                    6 45v ac
                    7 45v ac
                    8 45v ac
                    9 unused
                    10 45v ac
                    11 45v ac
                    12 6.5v ac
                    I have nothing as far as DC volts on any pins.
                    Can any of you gurus advise me on what I should check next.
                    My father was an electronics engineer and I worked in his place for a while so I do have a little knowlage.
                    I am also certified in soldering so thats not an issue.
                    He passed away a few years ago and i have nobody to repair this for me anymore.
                    Thanks for any help or insight you can give me.
                    Here are some pics of board i replaced the caps.



                    Comment

                    • Hammer034
                      New Member
                      • Jul 2019
                      • 6
                      • usa

                      #50
                      Re: Asus VW246H will not power on

                      Update on pin voltages while connected to mainboard.

                      Pins 7 and 8 = 5 volts DC
                      Pins 10 and 11= 5.38 volts DC

                      The numbers in previous post were with power supply disconnected from main board.

                      Thanks.

                      Comment

                      • Jagdtiger777
                        New Member
                        • Nov 2019
                        • 3
                        • Australia

                        #51
                        Re: Asus VW246H will not power on

                        Hi Hammer034,
                        I just fixed my Asus VW246H. It had periods when it would not turn on until it had a rest for a few days. It finally failed to turn back on after a black out in our area. I checked the power supply board and had the same 5v DC voltages at the connector to the main board as you indicated. On the main board I found a 3.3V regulator (G1084-33) this had 5v coming in but no 3.3v going out. So after replacing this regulator my monitor is working.
                        I hope this will help you.
                        Cheers.

                        Comment

                        • Hammer034
                          New Member
                          • Jul 2019
                          • 6
                          • usa

                          #52
                          Re: Asus VW246H will not power on

                          Originally posted by Jagdtiger777
                          Hi Hammer034,
                          I just fixed my Asus VW246H. It had periods when it would not turn on until it had a rest for a few days. It finally failed to turn back on after a black out in our area. I checked the power supply board and had the same 5v DC voltages at the connector to the main board as you indicated. On the main board I found a 3.3V regulator (G1084-33) this had 5v coming in but no 3.3v going out. So after replacing this regulator my monitor is working.
                          I hope this will help you.
                          Cheers.
                          Thanks for the reply.
                          I will look into it.
                          You say this is on the mainboard and not the power supply board,correct.
                          I will update after checking.
                          thanx

                          Comment

                          • Jagdtiger777
                            New Member
                            • Nov 2019
                            • 3
                            • Australia

                            #53
                            Re: Asus VW246H will not power on

                            Sorry I forgot I had a photo.
                            Attached Files

                            Comment

                            • Hammer034
                              New Member
                              • Jul 2019
                              • 6
                              • usa

                              #54
                              Re: Asus VW246H will not power on

                              Originally posted by Jagdtiger777
                              Sorry I forgot I had a photo.
                              Thanks.
                              Didnt check it yet.
                              Plus I been looking for that chip but havent found one yet just in case thats it.

                              Comment

                              • Hammer034
                                New Member
                                • Jul 2019
                                • 6
                                • usa

                                #55
                                Re: Asus VW246H will not power on

                                Thanks to jadgtiger777 my monitor is workin again.
                                It was the g1084-33 regulator on the mainboard (logic)
                                The regulator wasnt puting out any voltage.

                                Comment

                                • frica
                                  Member
                                  • Nov 2017
                                  • 37
                                  • Spain

                                  #56
                                  Re: Asus VW246H will not power on

                                  +1

                                  Comment

                                  • lukjoly
                                    New Member
                                    • Jun 2020
                                    • 3
                                    • France

                                    #57
                                    Re: Asus VW246H will not power on

                                    Hi folks,
                                    I'm facing the same issue with the Asus VW246H monitor. Power on works only every now and then. I followed the indications in this forum and the conclusion is that the voltage regulator (G1084-33) sometimes gives 3.3V sometimes does not hence I'm going to replace it with a similar chip easier to find on the market (AP1084-33) but...... I'm wondering if also the other power chip marked (see pict) 210138LA M819272B could be part of the power failure and so worth of replacing. Though, after extensive research I've not been able to identify this part.
                                    Any hint will be greatly appreciated.

                                    Thanks
                                    Luke
                                    Attached Files

                                    Comment

                                    • Jagdtiger777
                                      New Member
                                      • Nov 2019
                                      • 3
                                      • Australia

                                      #58
                                      Re: Asus VW246H will not power on

                                      Originally posted by lukjoly
                                      Hi folks,
                                      I'm facing the same issue with the Asus VW246H monitor. Power on works only every now and then. I followed the indications in this forum and the conclusion is that the voltage regulator (G1084-33) sometimes gives 3.3V sometimes does not hence I'm going to replace it with a similar chip easier to find on the market (AP1084-33) but...... I'm wondering if also the other power chip marked (see pict) 210138LA M819272B could be part of the power failure and so worth of replacing. Though, after extensive research I've not been able to identify this part.
                                      Any hint will be greatly appreciated.

                                      Thanks
                                      Luke
                                      Hi Luke
                                      The second regulator if my memory serves me right takes the 3.3V and puts out 1.2V that the push buttons use. So if the 3.3V regulator isn't working you will not get the 1.2V.

                                      Comment

                                      • lukjoly
                                        New Member
                                        • Jun 2020
                                        • 3
                                        • France

                                        #59
                                        Re: Asus VW246H will not power on

                                        Originally posted by Jagdtiger777
                                        Hi Luke
                                        The second regulator if my memory serves me right takes the 3.3V and puts out 1.2V that the push buttons use. So if the 3.3V regulator isn't working you will not get the 1.2V.

                                        Hi, thanks for reply, indeed in a rare moment of functioning of the 3.3V reg I was able to discover that that chip put out 1.2V .... at moment I've ordered abroad the compatible parts (5A 3.3V regulator and 1.3A 1.2V regulator) plus all the 6 caps installed on the board just to make sure. Waiting delivery.
                                        thanks
                                        Luke
                                        Last edited by lukjoly; 06-30-2020, 11:51 AM.

                                        Comment

                                        • magicsmoke12
                                          New Member
                                          • Jun 2020
                                          • 2
                                          • australia

                                          #60
                                          Re: Asus VW246H will not power on

                                          Hi all,

                                          Similar problem here with my VW246H.
                                          For quite a while it's had problems with turning back on when switched off (either by the power button or the mains).
                                          Dealt with it for a while by just leaving it on standby all the time but finally had to turn the mains off and now can't power up.

                                          When I plug in the AC cable there is a very brief flicker on the power LED but nothing else, did the tests from above and am getting 5v through the same pins as others to the mainboard, both 3.3V and 1.2V regulators test ok.

                                          Any other thoughts? It's a pretty old monitor at this point and probably just going to replace but thinking it might be worth a shot if it's an easy fix.

                                          Comment

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