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Memorex MLT3221 Red power LED pulsing

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    #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?
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    #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.

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      #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.

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        #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

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          #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

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            #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?

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              #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.

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                #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.

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                  #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

                    #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

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