Announcement

Collapse
No announcement yet.

Memorex MLT3221 no power

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Memorex MLT3221 no power

    Have a Memorex 32" tv will not power on set is dead.have checked large cab in center of power suppy board 158v. Checked con3 power is fluctuateing 5vSB 0 to 6v, 5V o to 1v, 12v 0 to 6v. The board is a Proview Ipos 150 Rev 3.3.I know there are some posts on this but there all over the place would like to start this fresh. Thank you for any help.

    #2
    Re: Memorex MLT3221 no power

    Look real close at all the caps, especially the ones under the heatsink on the right of the board. What you can also do is to unplug the TV, use the hair dryer to heat up the board for 3-4 minutes, then plug the TV in and monitor the 5VSTBY to see if it becomes stable, it sounds like it has bad start-up cap. The bad part is that you have to remove the hest sink to get to them. They are also known for having 2 bad 10uf 450vdc caps for the inverter section.
    http://s807.photobucket.com/albums/y...t=DSC04333.jpg
    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


      #3
      Re: Memorex MLT3221 no power

      Heated with hair dryer still voltage is pulsing

      Comment


        #4
        Re: Memorex MLT3221 no power

        You will need to inspect the caps real close, as suggested, the startup cap for the stby5V which is under the heatsink. Do you have ESR meter?
        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


          #5
          Re: Memorex MLT3221 no power

          My board doesn't have the 2 cabs you refer to 10uf 450 vdc. see picture of my board. also I have no ESR meter
          Attached Files

          Comment


            #6
            Re: Memorex MLT3221 no power

            They use the Poly caps instead.
            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


              #7
              Re: Memorex MLT3221 no power

              How do you check them? check like a cap?

              Comment


                #8
                Re: Memorex MLT3221 no power

                On this model there aren't any known failures with those caps and anyway the TV standby voltage would still be good as they only couple the drive to the inverter transformers.

                I see the disc on the main big capacitor (marked 25/105/V46) is bulging, try pressing this down, if you can depress it so it is flat the capacitor is OK, but if you can't then it could be failed.
                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                Comment


                  #9
                  Re: Memorex MLT3221 no power

                  Can not push it in

                  Comment


                    #10
                    Re: Memorex MLT3221 no power

                    The large cap on my board also has domed plastic cap, remove the top, it turns out to be the plastic cap is deformed but the metal cap is flat, you can remove the black disc and see.
                    It is hard to get to the start up caps since they are mounted under the heat sink. You may be able to fish it through the hestsink hole, you can see it in your pictures. The two caps on my board are lytics type your are Poly type and they are for the inverter circuits, you need to fix the 5CSTBY problem first to see if anything else are bad.
                    You can also check the DC on that large cap to see if it is fluctuating when the TV is OFF, when TV is on the PFC Voltage booster will kick in, then the voltage will go up to around 380-400vdc.
                    Attached Files
                    Last edited by budm; 01-09-2013, 12:07 PM.
                    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


                      #11
                      Re: Memorex MLT3221 no power

                      O.K you lost me on the large cap voltage going up to 380-400 volts. large cap has 185 volts and it does not fluctuate when power is off.

                      Comment


                        #12
                        Re: Memorex MLT3221 no power

                        when you try to turn the tv on does the voltage go up from 185 volts to about 380 volts on the large cap

                        Comment


                          #13
                          Re: Memorex MLT3221 no power

                          At this point it will probably not work since the processor does not have steady standby voltage to run the main board circuits. Need to get the stby fixed first.
                          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


                            #14
                            Re: Memorex MLT3221 no power

                            No it stays at 185 v

                            Comment


                              #15
                              Re: Memorex MLT3221 no power

                              https://www.badcaps.net/forum/showthread.php?t=12886
                              same power board i think maybe worth a read

                              Comment


                                #16
                                Re: Memorex MLT3221 no power

                                budm any ideas how to get the heat sink off this power board. do you de- solder it or will the corners pop off those tabs and un screw the components attached to it.

                                Comment


                                  #17
                                  Re: Memorex MLT3221 no power

                                  Originally posted by vinceroger69 View Post
                                  https://www.badcaps.net/forum/showthread.php?t=12886
                                  same power board i think maybe worth a read
                                  How do you check this diode referred to in the link above? There referring to a diode at D10.

                                  Comment


                                    #18
                                    Re: Memorex MLT3221 no power

                                    You have the advantage that you can see what D 10 looks like? Is it like D5 or D7
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment


                                      #19
                                      Re: Memorex MLT3221 no power

                                      Here's picture of diode at D10

                                      Comment


                                        #20
                                        Re: Memorex MLT3221 no power

                                        Try it again here's the picture of Diode at D10
                                        Attached Files

                                        Comment

                                        Working...
                                        X