Announcement

Collapse
No announcement yet.

Samsung UN24H4000AF red blinking

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Samsung UN24H4000AF red blinking

    Samsung UN24H4000AF LED tv whn turned on the front light either stays on steady and pushing the power blinks a few times then goes out. Never any backlight and nother ever on screeen using flashlight. I get 165v constant at the big cap and the 5 wire cord from the power to main I get 12.3v on 4 and ground on the other and does not matter if red light is on or off in front. I was thinking the main but am not sure what to test next. Thanks in advance for any help!
    Attached Files

    #2
    Re: Samsung UN24H4000AF red blinking

    Measure on the PSU the CNM803 connector all pins and post them. Then disconnect the main board and plug the TV in, the backlights should come on.

    Comment


      #3
      Re: Samsung UN24H4000AF red blinking

      Yes that's the connector I was talking about it's actually 12.9volts pin 1-4 then 5 is nothing. Unplugging that connector then powering the board still no backlight so Power board shot?

      Comment


        #4
        Re: Samsung UN24H4000AF red blinking

        O.k. maybe the PSU doesn't have a pull up resistor to fire up the backlights. I haven't seen a schematic for it.
        You wont see more than 170V on the main filter cap, as the PSU is not getting turned on (no PSon) and thus the PFC isn't working. With the PFC working, voltage on the main filter cap is >360V DC.

        Nothing on pin5 is bad. That defiantly indicates a bad main board. I guess you need a new replacement board. You could try to trace back the PSon signal on the main board, but I had not much luck fixing an issue like that as mostly the main IC was bad.

        You can try to unplug the PSon pin from the connector and jump 13V DC through a 1k resistor on it and force the PSU on?
        Last edited by CapLeaker; 12-02-2015, 04:53 PM.

        Comment


          #5
          Re: Samsung UN24H4000AF red blinking

          You need to report the readings of all 10 pins and follow each pin with pin names per chart as printed on the board: CONNECTOR:CNM803.
          Per chart:
          PIN 1, 3, 5, 7 are A13V (Always on 13V)
          PIN 8, 9, 10 are GND
          PIN 2: OD_UD
          PIN4: BLU_PWM
          PIN 6:PWR ON/OFF

          The ODD pins can be access form the top side of the board.
          The EVEN pins are accessed from the bottom side of the board.

          This power supply does not have PFC Voltage booster due to low power and it only has only one transformer and it is always running.
          Pictures provided by SHOPJIMMY.
          Attached Files
          Last edited by budm; 12-02-2015, 05:36 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


            #6
            Re: Samsung UN24H4000AF red blinking

            Well CapLeaker bad guess. Got the new main today and same thing. Even went as far as taling the LED's out and testing them. Wish I would have seen budm's post before I ordered it. Out $25

            Comment


              #7
              Re: Samsung UN24H4000AF red blinking

              1,3,5,7 are all 12.9v
              2=3.2v
              4=1.5v
              6=5.4v
              8,9,10 are good ground.

              Comment


                #8
                Re: Samsung UN24H4000AF red blinking

                Originally posted by CraigR View Post
                1,3,5,7 are all 12.9v
                2=3.2v
                4=1.5v
                6=5.4v
                8,9,10 are good ground.
                So 2, 4, and 6 change state when the power switch is toggle ON and OFF?
                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


                  #9
                  Re: Samsung UN24H4000AF red blinking

                  Samsung BN44-00746A
                  BTW, you need to check the DCV of the LED connector CNL802 pins with and without the connector in place when TV is ON. I have a feeling you have bad LEDS.
                  Last edited by budm; 12-10-2015, 02:44 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: Samsung UN24H4000AF red blinking

                    No change in voltage when on/off button toggled in 2,4 and 6
                    I have 18V on the LED connector. I removed the LED's and tested each bulb with a bench power source and all of them lit. I also noticed the led in the digital audio connector always stays on when toggling the on/off switch.

                    Comment


                      #11
                      Re: Samsung UN24H4000AF red blinking

                      Can I check the power without other boards?
                      What to include on the PowerOn?

                      Comment


                        #12
                        Re: Samsung UN24H4000AF red blinking

                        In what way is your tv malfunctioning vankbg? be as specific as you can.

                        Comment


                          #13
                          Re: Samsung UN24H4000AF red blinking

                          No power. Red LED is not illuminated.
                          Board power supply - checked, MOS, Diode ,.
                          There are 375 V input capacitor.
                          There is no output voltage.
                          I measure when the power circuit is disconnected from the TV.

                          Comment


                            #14
                            Re: Samsung UN24H4000AF red blinking

                            Don't understand "I measure when the power circuit is disconnected from tv". Did you try disconnect cable from powerboard to mainboard leave it out, then plug power cord into powerboard, do backlights come on and stay on?

                            Comment


                              #15
                              Re: Samsung UN24H4000AF red blinking

                              I measure when the power board is disconnected from tv(Mother board and LED) Only Power 220V

                              Comment


                                #16
                                Re: Samsung UN24H4000AF red blinking

                                Power suppay works without you plug to Mother board?

                                Comment


                                  #17
                                  Re: Samsung UN24H4000AF red blinking

                                  It's a test to try to verify powerboard and backlights, don't be afraid no harm if done as instructed.
                                  Last edited by nomoresonys; 11-12-2019, 09:40 AM.

                                  Comment


                                    #18
                                    Re: Samsung UN24H4000AF red blinking

                                    Many thanks for your attention @nomoresonys !!!
                                    I repaired the power supply.
                                    The problem was PHOTOCOUPLER LTV-817B.
                                    I changed and everything is fine!
                                    Once again many thanks and all good!

                                    Comment


                                      #19
                                      Re: Samsung UN24H4000AF red blinking

                                      Good to hear, thanks for the feedback.

                                      Comment


                                        #20
                                        Re: Samsung UN24H4000AF red blinking

                                        Dear budm, can you help me?
                                        My TV(Samsung UE40JU6400W) still illuminated RED standby LED on front. The voltages on powersupply are:
                                        when mainboard is unplugged - connector CNM803 (then the LED backlight is switched on)
                                        1. F/C 0,26V
                                        2. A/D 2,67V
                                        3. A13V 12,7V
                                        4. OD_UD 3,53V
                                        5. A13V 12,7V
                                        6. BLU_PWM 3,11V
                                        7. A13V 12,7V
                                        8. POWER ON/OFF 3,86V
                                        9. A13V 12,7V
                                        10. GND 0V
                                        11. GND 0V
                                        12. GND 0V

                                        If I connect mainboard then the backlight is turned off and there are those voltages:

                                        1. F/C 3,20V
                                        2. A/D 3,26V
                                        3. A13V 9,28V
                                        4. OD_UD 0,0V
                                        5. A13V 9,28V
                                        6. BLU_PWM 0,0V
                                        7. A13V 9,28V
                                        8. POWER ON/OFF 0,9V
                                        9. A13V 9,28V
                                        10. GND 0V
                                        11. GND 0V
                                        12. GND 0V

                                        Is it bad mainboard, inst it?
                                        Thank you,
                                        Juraj

                                        Comment

                                        Working...
                                        X