Dead NEC E655 - Can't find the service manual

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  • emilime75
    Member
    • Jan 2010
    • 18

    #1

    Dead NEC E655 - Can't find the service manual

    Picked this up last week. It was used in an office setting and "one day it just wouldn't turn on". LED on the front of it shows no life. I've got it opened up and the first thing I checked were the 2 large rectifiers on the power supply(this was the problem on a Sharp I fixed a few months ago).

    Now, either there is something odd happening with both rectifiers, or my meter is on the fritz...supply voltage always reads good at about 160vdc, but the 2 drop legs sometimes read good at about 80vdc, but sometimes I get no reading, and it seems to be random and it's happening on both rectifiers...like I'll measure once and it's good, move the meter probes around to different legs, and all of a sudden there's no voltage on the drop legs, but always shows around 160 on the input.

    Shouldn't a rectifier always be "on" and always have voltage on all legs, except for ground, obviously? And why are there 2 of them? Part number TS10P06G.

    Thanks.
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Dead NEC E655 - Can't find the service manual

    " but the 2 drop legs sometimes read good at about 80vdc" What the heck are the 'DROP LEGS'?
    How about providing good clear pictures so we can see what we are dealing with?
    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

    • emilime75
      Member
      • Jan 2010
      • 18

      #3
      Re: Dead NEC E655 - Can't find the service manual

      Please excuse me if my terminology is incorrect. I'm just mostly a doofus trying to fix a TV.

      The "2 drop legs" mentioned are the 2 middle leads.


      Here's the spec sheet for the rectifier in question
      https://cdn.badcaps-static.com/pdfs/...3636e9775e.pdf

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #4
        Re: Dead NEC E655 - Can't find the service manual

        I cannot see the pictures. Did you use the attachment in the 'Go Advanced'?
        Last edited by budm; 01-20-2020, 03:17 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

        • emilime75
          Member
          • Jan 2010
          • 18

          #5
          Re: Dead NEC E655 - Can't find the service manual

          I didn't post any pictures. The link to the rectifier spec sheet works, at least it just did for me.

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #6
            Re: Dead NEC E655 - Can't find the service manual

            I do not need the spec of the bridge.
            I need to see the pictures of the board so we can see how the bridges are connected and also other circuit as well. Also need the pictures of the whole backside of unit showing all the boards.
            "supply voltage always reads good at about 160vdc, but the 2 drop legs sometimes read good at about 80vdc," Why do you use DC mode on the meter when measuring the two inner pins of the bridge when they are fed by AC?
            The 120 VAC (if that is the power line Voltage of your country since you do not indicate what that is) must have been present otherwise you will not have 160VDC between the + and - legs of the bridge.
            What did you use for meter ground when working on this bridge section?
            Last edited by budm; 01-20-2020, 03:57 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

            • emilime75
              Member
              • Jan 2010
              • 18

              #7
              Re: Dead NEC E655 - Can't find the service manual

              Had to step away from this for a bit, back at it now.
              Any assistance would be greatly appreciated.

              To recap, this guy is totally dead. No reponse from the buttons and nothing from the status LED.

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278

              https://www.badcaps.net/forum/attach...1&d=1582231278
              Attached Files
              Last edited by emilime75; 02-20-2020, 03:11 PM.

              Comment

              • R_J
                Badcaps Legend
                • Jun 2012
                • 9529
                • Canada

                #8
                Re: Dead NEC E655 - Can't find the service manual

                Check the voltage on J914/J915, it should be +12 volts. If you don't have this voltage, then check the voltage across C9103, Use J931 (hot ground) and check the cathode of D9103, this should be arouns 10~20vdc
                Last edited by R_J; 02-20-2020, 04:20 PM.

                Comment

                • emilime75
                  Member
                  • Jan 2010
                  • 18

                  #9
                  Re: Dead NEC E655 - Can't find the service manual

                  Nothing on jumpers 914 and 915.

                  Measuring across C9103, the meter bounces around between about 9-22VDC.

                  J931 to cathode of D9103, the meter bounces around between about 9-22VDC.

                  Comment

                  • R_J
                    Badcaps Legend
                    • Jun 2012
                    • 9529
                    • Canada

                    #10
                    Re: Dead NEC E655 - Can't find the service manual

                    Are you getting any voltage at all across C9105? Also check the resistance of R9101 to see if it is open, it should read 0.24Ω
                    Last edited by R_J; 02-20-2020, 06:40 PM.

                    Comment

                    • emilime75
                      Member
                      • Jan 2010
                      • 18

                      #11
                      Re: Dead NEC E655 - Can't find the service manual

                      Nothing across C9105.

                      R9101 measures .7 ohms, in circuit. I didn't remove it from the board to measure.

                      Comment

                      • emilime75
                        Member
                        • Jan 2010
                        • 18

                        #12
                        Re: Dead NEC E655 - Can't find the service manual

                        Bumping this. Hoping for some more assistance.

                        Thank you.

                        Comment

                        • R_J
                          Badcaps Legend
                          • Jun 2012
                          • 9529
                          • Canada

                          #13
                          Re: Dead NEC E655 - Can't find the service manual

                          Locate C9109, check the voltage across it. It looks like the ciruit is trying to start, thats why the voltage is jumping on C9103
                          Have a good look at the connections on the transformer, T9101 to make sure there are no poor solder connections.
                          There are two diodes D9104 & D9106, check that they are not shorted, they are on the back of the board near T9101.
                          If the diodes are ok, then I would try replacing C9103 and C9109, it could be they are bad.
                          Last edited by R_J; 02-26-2020, 11:04 PM. Reason: 715G6887

                          Comment

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