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    Samsung un49mu7000f dead no power

    Hi.
    I'm working on a Samsung UN49MU7000F that has no standby LED indicator.
    No POWER
    The power supply board is part number BN44-00876A
    The main board number is BN94-12399A
    I am stuck.
    I have replaced both pwr supply and main board with no changes.
    Here are some of the readings from my multi meter on various locations on my power supply

    MAIN BOARD UNPLUGGED. BACK LIGHTS ON PLUG CNL802 85 volts
    Backlights are all illuminated and in operating range.

    MB PLUG CNM803. - UNPLUGGED

    PIN 1 FAN COUNT - Open
    PIN 2 ANA DIM - Open
    PIN 3 A13V. - 12.89
    PIN 4 OD ON/OFF - 2.163
    PIN 5 A13V. - 12.89
    PIN 6 PWM BLU - 2.106
    PIN 7 A13V - 12.89
    PIN 8 PWR ON - 1.665
    PIN 9 A13V - 12.89
    PIN 10 GND- GND
    PIN 11 GND -GND
    PIN 12 GND-GND
    STB VOLTAGE TEST POINT ON BOARD 12.89. (Should read 7.5 and 11.8)

    With MB PLUGGED IN. NO BACKLIGHTS.

    MB PLUGGED IN CNM803 READINGS

    Pin 1 FAN COUNT open
    Pin 2 ANS DIM open
    Pin 3 A13V 9.03
    Pin 4 OD ON/OFF open
    Pin 5 A13V 9.03
    Pin 6 PWM BLU 34 ohms
    Pin 7 A13V 9.03
    Pin 8 PWR ON open
    Pin 9 A13V 9.03
    Pin 10 GND. gnd
    Pin 11 GND gnd
    Pin 12 GND gnd
    STB VOLTAGE AT TEST POINT 9.03

    I'm just not sure of what voltages should be reading at CNM803.
    Any help would be appreciated!
    Attached Files

    #2
    Re: Samsung un49mu7000f dead no power

    It’s the main board. If backlights work with mb disconnected that mean power board is good. You must have got a defective mainboard. Even if the panel was bad the standby light would be on when the tv is off.

    Comment


      #3
      Re: Samsung un49mu7000f dead no power

      I actually just fixed one with similar issue. It’s the eeprom on the main board causing the problem. See if you can find a replacement eeprom on shopjimmy or eBay

      Comment


        #4
        Re: Samsung un49mu7000f dead no power

        Hi,
        I have replaced the main board with 2 different replacement boards from TV PARTS TODAY and also replaced the power supply board once with no change.
        (Am I getting defective boards from TVPARTS TODAY? They’re supposed to be fully tested before shipping)

        I’m a little curious to why I’m not getting the 3 VDC standby voltage.
        I’m just not sure what voltages I’m supposed to be getting on CNM 803 as they aren’t marked on the PS board.

        Comment


          #5
          Re: Samsung un49mu7000f dead no power

          Originally posted by bstewara View Post
          I’m a little curious to why I’m not getting the 3 VDC standby voltage.
          I’m just not sure what voltages I’m supposed to be getting on CNM 803 as they aren’t marked on the PS board.
          The voltages and pin numbers for CNM803 are clearly marked on the BN44-00876A power supply board.
          There is no 3.3 volt standby supplied by this power supply, only A13v The main board supplies all the other lower voltages.
          With power removed, disconnect the two cables going to the panel, plug in tv and see if it will turn on (there will be no picture)
          Last edited by R_J; 10-12-2021, 06:15 PM.

          Comment


            #6
            Re: Samsung un49mu7000f dead no power

            Unfortunately tvpartstoday doesn’t really know which boards are good. I’ve had several main boards from them that are defective.

            Now they don’t even ask me to return them for the refund.
            There prices are good and so is there return policy. So I still use them as a last resort sometimes.

            I’m almost positive it’s the main board. Unfortunately they are getting harder to find for the mu series TVs.

            Comment


              #7
              Re: Samsung un49mu7000f dead no power

              Thanks Much
              I will try and find another MB .

              Comment


                #8
                Re: Samsung un49mu7000f dead no power

                Originally posted by bstewara View Post
                Thanks Much
                I will try and find another MB .
                If you have a programmer, then read the dump from the spi flash ic1604 W25Q40CL and put it here, I will fix it for you and you will write it back and your samsung will work.

                Comment


                  #9
                  Re: Samsung un49mu7000f dead no power

                  Hi,
                  I'm not seeing ic1604
                  However I found ic1603 (25q80dvsig). (1733)
                  Could this be the correct ic for this model?

                  Thanks again

                  Comment


                    #10
                    Re: Samsung un49mu7000f dead no power

                    Originally posted by bstewara View Post
                    Hi,
                    I'm not seeing ic1604
                    However I found ic1603 (25q80dvsig). (1733)
                    Could this be the correct ic for this model?

                    Thanks again
                    Do you have a mainboard BN41-02568B?
                    Attached Files

                    Comment


                      #11
                      Re: Samsung un49mu7000f dead no power

                      BN41-02568B

                      IC901 SDP1601 ver.05 S5WWPT H1730
                      IC701 KLM461FEPD
                      IC1001,1101 K4F8E30 4HBMGCH
                      IC1604 25Q40CLSIP
                      IC1603_UT_KTN 25Q80DVSIG
                      IC201 AWR7GB
                      IC303 54627 TI 76A P42CG3
                      IC203,IC207 T282 2897
                      IC400_UT VPM1R0A 728205A
                      IC209,IC2301 LR1801G
                      IC802 10358 7271
                      IC801 24512FD
                      IC204 T21T G942
                      IC401_PFFU VLS1R0A 726432A
                      IC302 T297 5334
                      IC1901_CI 74LCX244 OH301
                      IC2302_DS 65235 TI 781 AQ9G
                      IC301,IC206,IC202,IC205 3201
                      IC1402,IC1401 18PF


                      Remove the radiator.
                      Attached Files
                      Last edited by lotas; 10-26-2021, 09:06 AM.

                      Comment


                        #12
                        Re: Samsung un49mu7000f dead no power

                        No,
                        I’m sorry my main board is BN94-12399A

                        Thanks

                        Comment


                          #13
                          Re: Samsung un49mu7000f dead no power

                          Hi,

                          I did find it!
                          Thanks for the photo.

                          Do you know if this ic can be purchased pre flashed and ready to install?
                          I don’t have a programmer

                          Thank you for all of your help

                          Comment


                            #14
                            Re: Samsung un49mu7000f dead no power

                            Originally posted by bstewara View Post
                            No,
                            I'm sorry my main board is BN94-12399A

                            Thanks
                            Why not?
                            Attached Files

                            Comment


                              #15
                              Re: Samsung un49mu7000f dead no power

                              I don't know where to buy this microcircuit, buy the simplest CH341 programmer.

                              Comment


                                #16
                                Re: Samsung un49mu7000f dead no power

                                Hi lotus
                                I just want to thank you for your assistance!
                                You've been a great help!

                                Thank You

                                Comment


                                  #17
                                  Re: Samsung un49mu7000f dead no power

                                  Hi lotus,
                                  I ordered a programmer I will send you the dump from the spi flash next week sometime.
                                  Thanks again

                                  Comment


                                    #18
                                    Re: Samsung un49mu7000f dead no power

                                    @bstewara, Did you solve this problem?

                                    Comment


                                      #19
                                      Re: Samsung un49mu7000f dead no power

                                      Sorry
                                      No I did not.
                                      I've had a difficult time finding software for the ch341 programmer.
                                      I think I'm going to try and find a pre programmed chip to install or purchase another main board.
                                      Not sure I have the expertise to repair flashing the chip.

                                      Regards

                                      Comment


                                        #20
                                        Re: Samsung un49mu7000f dead no power

                                        As far as I know, Asprogrammer is the best software for CH341A

                                        Comment

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