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Magnavox 37mf321d/37 Powers off for 5 seconds

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    Magnavox 37mf321d/37 Powers off for 5 seconds

    Hey All,
    I'm working on my 3rd Magnavox that had power up issues that I had fixed with the help of the forum. Thanks guys!!!
    This last one powers up now and have a good picture. Everything works well but it will randomly click off for 5-6 seconds and then power right back up on it's own. With a cold TV it will go for at least half an hour to 45 minutes maybe longer before this problem happens and it may happen every 5 minutes or every 20 minutes. It happens with the cable 75ohm, HDMI, composite, and Component inputs. It seems to be a heat issue. I have isolated the problem to the main board/scaler board. I had moved this board to my other two sets and the problem follows the board. The board does not have any apparent damage to any of the caps and I have tested them and they read fine on my digital volt meter. I know that I cannot truely test them because my meter does not have capacitance testing so I swaped them out with new 1000uf 25v capacitors and the problem persists. I have also cleaned the board and heat sink and applied new thermal compound as well.
    What other parts would any of you suggest I check? I have found a few other boards out there for between $40 and $120...wonder if I'd be best served to just get a known good one but where is the fun in that? lol
    Thanks!!!
    Last edited by mguzinski; 12-19-2012, 02:08 PM.

    #2
    Re: Magnavox 37mf321d/37 Powers off for 5 seconds

    You might be able to isolate the area of the circuit board where the problem is with a can of air turned upside down to produce cold spray and a electric hair dryer for heat, try cold spray in small areas or particular components to see if it stops clicking off, or use heat from hair dryer in small areas to see if you can get it to fail sooner, or it could have bad solder connections.

    Comment


      #3
      Re: Magnavox 37mf321d/37 Powers off for 5 seconds

      You may have cold solder joints some where or failing components. But first try tighten all the board mounting screws to make sure they are not loose since some of the board ground circuits are done through the contact pads on the board and the chassis.
      Try using small wooden stick pushing on the boards to see if you can make it cuts out.
      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


        #4
        Re: Magnavox 37mf321d/37 Powers off for 5 seconds

        New update...
        The board was cleaned and installed and torqued properly. I installed the heat sink properly and the TV still had the same symptoms.
        I then went into the service menu 0,6,2,5,9,6,info and looked for errors. No errors, I then checked Defective module and none. I then did the Reset error buffer an don't really know if I did it properly because it did not show any progress but for 4 days running for at least 3 hours at a time no shut offs. I did the Reset by going to the menu then start now then ok. Is this the correct way to do the reset or is it just a fluke?
        Thanks.

        Comment


          #5
          Re: Magnavox 37mf321d/37 Powers off for 5 seconds

          Hey guys. Been forever since I've been on here. Two kids later, a grandchild and a job change later, I'm back at fixing this same issue. I want to get this TV working for my son for his house. I have determined the issue is the scaler board by swapping it into a working TV and having the same issue. The issue now is the actual board compatibility. My board is a 3138 103 6284.4 and I have a line on a board 3138 103 6284.3. Now when I check on parts interchange and with Magnavox/Phillips they cross reference each other. Does anyone know if they are truly compatible?
          Thanks All,
          Mike

          Comment


            #6
            Re: Magnavox 37mf321d/37 Powers off for 5 seconds

            Originally posted by mguzinski View Post
            Hey guys. Been forever since I've been on here. Two kids later, a grandchild and a job change later, I'm back at fixing this same issue. I want to get this TV working for my son for his house. I have determined the issue is the scaler board by swapping it into a working TV and having the same issue. The issue now is the actual board compatibility. My board is a 3138 103 6284.4 and I have a line on a board 3138 103 6284.3. Now when I check on parts interchange and with Magnavox/Phillips they cross reference each other. Does anyone know if they are truly compatible?
            Thanks All,
            Mike
            Maybe worth looking on shopjimmy compatibility list for each board and see if these will work in your tv if there on the site im sure they will work.
            Last edited by vinceroger69; 01-29-2017, 10:15 AM.

            Comment


              #7
              Re: Magnavox 37mf321d/37 Powers off for 5 seconds

              Originally posted by vinceroger69 View Post
              Maybe worth looking on shopjimmy compatibility list for each board and see if these will work in your tv if there on the site im sure they will work.
              That is one of the sites I checked. They of course no longer have either board available. I am also noticing the boards are used in everything from a 26" to 47" TV but mine has a 37 hand written on one of the white pads others I am seeing have 32 written...Wondering if that makes a difference???
              Thanks for the suggestion!

              Comment


                #8
                Re: Magnavox 37mf321d/37 Powers off for 5 seconds

                they may still tell you if it will work maybe email them/live chat with them they do seem a good company to deal with.

                Comment


                  #9
                  Re: Magnavox 37mf321d/37 Powers off for 5 seconds

                  http://www.ebay.com/itm/Magnavox-Mai...-/322003552448
                  Willing to help but I'm no expert.

                  Comment


                    #10
                    Re: Magnavox 37mf321d/37 Powers off for 5 seconds

                    Yes, I saw that too but it's a non working board. I also found this too http://www.ebay.com/itm/Philips-3138...4AAOSw241YjRcb which is a 31381036284.3 but the sticker barcode is same as mine 313815866271. Also found this one http://www.ebay.com/itm/Main-Board-3...IAAOSwiYFXK8kF
                    The board number is the same as my bad one but the barcode does not match mine. So what is the compatibility factor with Phillips/Magnavox (sticker barcode or board#) ?

                    Comment


                      #11
                      Re: Magnavox 37mf321d/37 Powers off for 5 seconds

                      i would go with the one that the sticker barcode matches at that price you cant go wrong either

                      Comment


                        #12
                        Re: Magnavox 37mf321d/37 Powers off for 5 seconds

                        Originally posted by vinceroger69 View Post
                        i would go with the one that the sticker barcode matches at that price you cant go wrong either
                        Yeah...I bought it, for that price could just take a chance. I'll post up if that actually is a true replacement.

                        Comment

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