Emerson LF501EM4F

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  • OldEE
    New Member
    • Oct 2017
    • 9
    • USA

    #1

    Emerson LF501EM4F

    My first post (besides the mandatory introduction).

    I have an Emerson LF501EM4F, found it curbside for free. No remote. Ebay has lots of those. Would rather not buy one until I know I can use it.

    TV is nothing but black screen. Flasing red power LED is only sign of life. Pressing buttons on back has no effect. LED flashes when you plug it in, never stops. TV never comes on. No backlight, no audio, no apparent video even with bright flashlight illumination. TV draws only 5 watts (140 shy of normal as stated on back of set).


    Made by Funai:


    Power supply board S/N:



    Main board:


    Keypad:


    IR sensor board (Not photographed yet) has S/N BA3AU0G0203 1 __1.

    Haven't taken the TV apart enough to see LED strips or LED driver board yet

    I found the service manual by searching this forum. Thanks! Digesting...

    A couple of other threads here about problems with this TV. I gather it's a bit of a POS. I tried some of the other suggestions but as yet have not made any progress. I would like to get it working.

    I have decades of EE experience. I can solder professionally. I come from the days of vacuum tubes and discrete transistors though. Recently did some SMD work without issues other than a lot of cursing. Feel like I can tackle this. Worth a try, maybe?

    Where should I start?
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Emerson LF501EM4F

    Start by checking Voltages on that power supply board, at least the standby power supply is working.
    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

    • dskall
      Badcaps Legend
      • Oct 2016
      • 2905
      • usa

      #3
      Re: Emerson LF501EM4F

      Need voltages from connector that goes from power supply board to main board. Will need pin#- PIN DESCRIPTION -Pin voltage in standby-Pin voltage when pushing power button and picture of connector on power supply board.
      Format:
      Pin# - Pin Description - Pin Voltage standby - Pin voltage power on
      1 - XXXXXXX - XXv - XXXv
      2 - XXXXXXX - XXXv - XXXv
      3 - XXXXXXX - XXXv - XXXv
      4 - etc.
      I assume no responsibility for any stupid suggestions I might post.

      Comment

      • OldEE
        New Member
        • Oct 2017
        • 9
        • USA

        #4
        Re: Emerson LF501EM4F

        Will do. Measurements to follow today.

        A few more photos to get us up to speed.

        Back has a removable cover just over the boards. That's removed. Entire back could come off if LED or LCD panels need to be investigated.


        PS board and main board, connected by one ribbon cable. Top cable on main board appears to be LCD driver. Bottom-left cable on main board goes to IR sensor board. Bottom right wires are speakers. Left wires on PS board I assume are LED strip supply. Bottom center cable on PS board is AC120V mains supply. Control buttons are wired directly to IR sensor board.



        Closeup of cable attaching to main board.


        Super closeup of pins on mainboard. Will measure here.


        High resolution shot of PS board. No capacitors appear vented. no obvious heat failures or burn marks.


        Voltage measurements and pin IDs to follow.

        Thanks.

        Comment

        • dskall
          Badcaps Legend
          • Oct 2016
          • 2905
          • usa

          #5
          Re: Emerson LF501EM4F

          You can upload pictures through go advanced/manage attechments
          I assume no responsibility for any stupid suggestions I might post.

          Comment

          • OldEE
            New Member
            • Oct 2017
            • 9
            • USA

            #6
            Re: Emerson LF501EM4F

            Ok will do from now on.

            Comment

            • OldEE
              New Member
              • Oct 2017
              • 9
              • USA

              #7
              Re: Emerson LF501EM4F

              Measurements:



              Also attached, note from service manual confirms my set is TYPE B, given the DS2 serial number. I'm currently using off-grid solar and my inverter is a little high, as shown in the Kill-a-Watt. I'm thinking the Power Supply board is ok. I guess these TVs jump into self-protection mode at the drop of a hat, if that's what it's doing.

              What to do next?

              Thanks.
              Attached Files

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Emerson LF501EM4F

                It looks like your meter battery may be low because the readings are showing higher thane normal, I.E. 3.3V shows 4.14V.
                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

                • OldEE
                  New Member
                  • Oct 2017
                  • 9
                  • USA

                  #9
                  Re: Emerson LF501EM4F

                  Originally posted by budm
                  It looks like your meter battery may be low because the readings are showing higher thane normal, I.E. 3.3V shows 4.14V.
                  You are correct. Batteryless analog meter has 3.3V, 12.7V and 21.2V readings dead on.

                  Protect3, Backlight-SW, and Backlight-ADJ are drastically low. The remaining readings are within reason.

                  Comment

                  • OldEE
                    New Member
                    • Oct 2017
                    • 9
                    • USA

                    #10
                    Re: Emerson LF501EM4F

                    The 12 and 21V supplies momentarily dip 10% when the red power LED blinks off (but not for the entire duration of the off cycle), as though something is trying to boot up. The 3.3V line does not dip.

                    The digital meter has the little battery icon displaying -- I guess that should have been a clue. I thought perhaps my 129V mains was the cause of high readings. Not so.

                    I tried it when I found it on city power. Same behavior then. My inverter sine wave isn't perfect here but it doesn't seem to affect computers or other LCD monitors. Am assuming it's OK for this TV too.
                    Last edited by OldEE; 10-05-2017, 02:10 PM. Reason: additional info

                    Comment

                    • RJARRRPCGP
                      Badcaps Legend
                      • Jul 2004
                      • 6304
                      • USA

                      #11
                      Re: Emerson LF501EM4F

                      Originally posted by OldEE

                      Not so.
                      If you keep getting 129 V, then expect a bad neutral connection... Let me guess: around 125 V with no big appliances on
                      and then with one major appliance on, it jumps to 129 V and then 132 V or the like with 2 major appliances on, when reading from the leg that's not under high load...
                      Last edited by RJARRRPCGP; 10-05-2017, 04:51 PM.
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                      "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

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                      "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                      "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                      Comment

                      • OldEE
                        New Member
                        • Oct 2017
                        • 9
                        • USA

                        #12
                        Re: Emerson LF501EM4F

                        No, just using a cheap inverter that's not very accurate. Not 3-phase, so no other leg. Saving up for a whole-house unit when I get more solar panels put up. It's an evolving project.

                        Back to the TV...

                        Comment

                        • RJARRRPCGP
                          Badcaps Legend
                          • Jul 2004
                          • 6304
                          • USA

                          #13
                          Re: Emerson LF501EM4F

                          Originally posted by OldEE
                          No, just using a cheap inverter that's not very accurate. Not 3-phase, so no other leg. Saving up for a whole-house unit when I get more solar panels put up. It's an evolving project.

                          Back to the TV...
                          Cool. Did you see my 2016 posts of the crappy neutral at 285 Clinton St. in Springfield, Vermont?
                          Last edited by RJARRRPCGP; 10-05-2017, 06:06 PM.
                          ASRock B550 PG Velocita

                          Ryzen 9 "Vermeer" 5900X

                          32 GB G.Skill RipJaws V F4-3200C16D-32GVR

                          Arc A770 16 GB

                          eVGA Supernova G3 750W

                          Western Digital Black SN850 1TB NVMe SSD

                          Alienware AW3423DWF OLED




                          "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                          "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                          "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                          "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                          Comment

                          • jackfish
                            Senior Member
                            • Dec 2016
                            • 89
                            • canada

                            #14
                            Re: Emerson LF501EM4F

                            check out capwizard thread.......https://www.badcaps.net/forum/showth...ight=LF501EM4F

                            Comment

                            • OldEE
                              New Member
                              • Oct 2017
                              • 9
                              • USA

                              #15
                              Re: Emerson LF501EM4F

                              Originally posted by jackfish
                              There are 5 or 6 threads about this TV here.

                              The one with 111 replies was the most thorough. I read them all before joining and starting my own thread (and finding the service manual). Now that I am getting more acquainted with the set I will read them all again.

                              Apparently I need to jumper high the protect lines and backlight lines to fool the PS board into thinking the fault is not there, and then try to find the fault by observing how the TV behaves. Just want to make sure I know how to do that safely...

                              Comment

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