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bn44-00264a Does anyone like a puzzle? Please help!

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    bn44-00264a Does anyone like a puzzle? Please help!

    So I've got the dreaded bn-44-00264a with no power. After a kit from my favorite supplier Shopjimmy, the TV works... once. And only if you hit the power button RIGHT AFTER you plug it in. Otherwise the standby light goes out after a few seconds and the TV is a paperweight.

    Using chassis as ground. Voltage at collector of QB801 is -50v to -122v and it's cyclical, (YES, negative and I'm lost at this one because I'm to understand there to be some 15v there) It drops to -80.4v and holds. Strandby light will come on shortly after for a brief time (5 seconds or so) it's at this point that you can again turn on the TV and it will operate normally. If you do not turn the TV on, the standby light will go out, the voltage will (decrease?) to ~-120v then repeat itself.

    Sidenote, I'm using a 50" Panasonic plasma I got for $60 with a bad SS board I repaired using your forums with little to no experience. I bought the TV gambling I could fix it. It was before shopjimmy had a kit and the guy had digikey part numbers he had researched and *thought* would work. I trusted him and bought the parts, since I live in the town they're based in. TV's been a computer monitor for 3 years now. Since then I've repaired probably 50 TV's and various electronics just due to people who were willing to help others with their knowledge. I am in your debt already. Thank you in advance for all your help!

    #2
    Re: bn44-00264a Does anyone like a puzzle? Please help!

    You are using the the wrong ground that is why you are getting wrong readings, you are working in the hot side of the circuit so the negative leg of the main filter cap is GND ref. for the hot side of the circuit.
    The key point right now is:
    Are you getting steady 5V standby Voltage to run the main board?
    Last edited by budm; 10-14-2017, 10:00 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


      #3
      Re: bn44-00264a Does anyone like a puzzle? Please help!

      Hi budm I've seen you around and I appreciate your help for sure. The answer is yes, I have 5v standby, but only for about 5 seconds or so after plugging it in. As far as I can tell all voltages are correct when the TV is on, and for a short time after you plug it in, then I lose voltage. That's why I'm so confused!

      Comment


        #4
        Re: bn44-00264a Does anyone like a puzzle? Please help!

        OK, for 5VSTBY not to be stable it can be due to being over loaded by the main board, or the power supply circuit is weak due to such thing as bad startup/running caps.
        So disconnect the cable between the power supply board and the main board and then check the standby Voltage to see if it is steady or not first.
        We must have steady standby Voltage 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


          #5
          Re: bn44-00264a Does anyone like a puzzle? Please help!

          Steady 5.22v (spec 5.3), backlights fire just fine. Did this before to try to rule out the power board and came to the conclusion that the main board was probably good because it fires if I'm quick on the power button so I went back to the PSU thinking I messed something up... Have I been chasing my tail this whole time? What could go wrong with the main that the TV would still function but not stay in standby? No 5v return? I didn't check that but I thought that was only on when the TV was on.

          Comment


            #6
            Re: bn44-00264a Does anyone like a puzzle? Please help!

            Can you link us to the kit at SHJ?

            Comment


              #7
              Re: bn44-00264a Does anyone like a puzzle? Please help!

              Are you confident to measure the voltage accross these caps? You can attach the negative probe to the heatsink in the hot side and with the red probe try to touch the positive leg (if you can) of these capacitors.
              These caps are connected to the lines which feed the main driver of the nearby transformer. They must have a steady 9-15V.
              Attached Files

              Comment


                #8
                Re: bn44-00264a Does anyone like a puzzle? Please help!

                They dont give the part numbers. We will have to do some research on a board we may have laying around.
                Attached Files

                Comment


                  #9
                  Re: bn44-00264a Does anyone like a puzzle? Please help!

                  This is what I bought and the power board seems to be working but just won't hold standby voltage. I'm comfortable testing anything senndogg, I'll be home in 15 minutes to give you the results

                  http://www.shopjimmy.com/samsung-bn4...repair-kit.htm

                  Comment


                    #10
                    Re: bn44-00264a Does anyone like a puzzle? Please help!

                    Those parts seem to be if the inverter circuit failed, with CNM802 unpluged from the main board, the power supply should turn on ie: 5 volts & 13 volts and the inverter/backlights should turn on also as there circuits have pullup resistors
                    5 volts standby should be constant
                    If those voltages are there and stay there, there could be excesive load on the main board for the switched +5 or +13 volts which would also load the +5 standby circuit
                    If the +13 volts drops there could be a fault on the power supply as that voltage does supply part of the inverter circuit
                    with main board disconnected short pin 1 (on/off) on cnm802 to chassis ground, the standby voltage should remain constant
                    Last edited by R_J; 10-16-2017, 04:49 PM.

                    Comment


                      #11
                      Re: bn44-00264a Does anyone like a puzzle? Please help!

                      Senndogg I've pulled these caps and put them in a tester and they're good at least.

                      With TV functioning properly -
                      cb804 0v
                      Cm804 17.6v

                      In failed standby -
                      Cb804 0v
                      Cm804 4.4

                      Comment


                        #12
                        Re: bn44-00264a Does anyone like a puzzle? Please help!

                        You said the backlight turns on fine when you disconnect the mainboard? So mainboard is pulling the voltage down?
                        I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                        Comment


                          #13
                          Re: bn44-00264a Does anyone like a puzzle? Please help!

                          If that voltage is dropping that means that sth is overloading the whole system. After some minutes of working tv can you check the mainboard for excessive heating components? The processor itself should not exceed 65'C.

                          Comment


                            #14
                            Re: bn44-00264a Does anyone like a puzzle? Please help!

                            He has no standby voltage when mainboard is connected. Disconnected the mainboard and the 5v is back.

                            My guess is bad bga solder on mainboard ( CPU ).

                            any history on the tv?
                            I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                            Comment


                              #15
                              Re: bn44-00264a Does anyone like a puzzle? Please help!

                              Im actually in the process of installing this same kit now.

                              Comment


                                #16
                                Re: bn44-00264a Does anyone like a puzzle? Please help!

                                Originally posted by tvtimmy View Post
                                They dont give the part numbers. We will have to do some research on a board we may have laying around.
                                part numbers are on the components and on the bags each component comes in for my kit? I dont believe its the shop jimmy kit though... I can post the part numbers after work if you still need them?

                                EDIT* I have this kit myself.. http://www.ebay.com/itm/Samsung-BN44...72.m2749.l2649
                                Last edited by augiedoggy; 10-17-2017, 06:25 AM.

                                Comment


                                  #17
                                  Re: bn44-00264a Does anyone like a puzzle? Please help!

                                  Hi guys, sorry to revive an old post but am having an issue where I do not have no voltages on the CNM802 connector with the cable disconnected from the main board. The 2 fuses are both working. The Tv just stop working. Any help will be appreciated.
                                  Thanks

                                  Comment


                                    #18
                                    Re: bn44-00264a Does anyone like a puzzle? Please help!

                                    Lets see good clear straight shots pictures of the the whole top and bottom side of YOUR board using 'Go Advanced' to attach the pictures.
                                    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


                                      #19
                                      Re: bn44-00264a Does anyone like a puzzle? Please help!

                                      Also check all the diodes, youtube is your friend for tutorials.

                                      Comment

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