Memorex MLT3221 Red power LED pulsing

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  • ntehicks
    Badcaps Veteran
    • Mar 2011
    • 272
    • United States
    #1

    Memorex MLT3221 Red power LED pulsing

    I just purchased this TV. when power is applied I get a pulsing flash from the red power led. but the TV won't turn on. the person I purchased it from just replaced all of the caps. not sure where to go from here. what to test?
    Attached Files
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    • Shinju
      Badcaps Legend
      • Mar 2014
      • 1239
      • USA
      #2
      Re: Memorex MLT3221 Red power LED pulsing

      Check D10 diode, this is the exact same power supply I have for a Polaroid 32".

      The first PS that was in the tv wouldn't turn on so I got a replacement ps that also end up failing after doing some research I found the first PS had a bad D10 diode.

      Also I replaced the Q16/Q17 N-channel transistors as they are notorious for going bad if the 10uf 450v caps have failed.

        Comment

        • ntehicks
          Badcaps Veteran
          • Mar 2011
          • 272
          • United States
          #3
          Re: Memorex MLT3221 Red power LED pulsing

          I checked D10 in circuit and it checks out ok. low ohms one way and high the other way. how would I check Q16 /Q17. would I check them in circuit.

            Comment

            • ntehicks
              Badcaps Veteran
              • Mar 2011
              • 272
              • United States
              #4
              Re: Memorex MLT3221 Red power LED pulsing

              I just noticed this on the bottom of the power board. not sure of this is normal or if someone made a modification.
              Attached Files

                Comment

                • ntehicks
                  Badcaps Veteran
                  • Mar 2011
                  • 272
                  • United States
                  #5
                  Re: Memorex MLT3221 Red power LED pulsing

                  I was tested on the primary side and came across D7 the part number is HER207 it is testing low ohms both directions.
                  Attached Files

                    Comment

                    • ntehicks
                      Badcaps Veteran
                      • Mar 2011
                      • 272
                      • United States
                      #6
                      Re: Memorex MLT3221 Red power LED pulsing

                      so I have ordered a replacment diode. is there anything else I should test before installing new diode and connecting power to the tv?

                        Comment

                        • ntehicks
                          Badcaps Veteran
                          • Mar 2011
                          • 272
                          • United States
                          #7
                          Re: Memorex MLT3221 Red power LED pulsing

                          replaced D7 and still get the same results. the front led blinks red and tv won't turn on. I at the same time ordered a full working power supply and tested the tv with that and TV works. I would like to figure out what is bad on this board. no 5 volt standby.

                            Comment

                            • ntehicks
                              Badcaps Veteran
                              • Mar 2011
                              • 272
                              • United States
                              #8
                              Re: Memorex MLT3221 Red power LED pulsing

                              is it possible to take this power supply and run it with out the other boards. I would like to trouble shoot the 5volts missing.

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA
                                  #9
                                  Re: Memorex MLT3221 Red power LED pulsing

                                  If the +5VSTBY is not working, you can run the power supply board by itself since +5VSTBY is an always on power supply so you can troubleshoot that +5VSTBY without having the board connected to anything else. Or you are talking about +5V (swithced).
                                  Last edited by budm; 05-23-2014, 08:48 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

                                    • Mark562
                                      Member
                                      • Jun 2014
                                      • 13
                                      • usa
                                      #10
                                      Re: Memorex MLT3221 Red power LED pulsing

                                      hello i noticed you tested Memorex MLT3221 power supply how would i check D10 in circuit . thank you

                                        Comment

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