Sceptre X505BV-FMDR

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #61
    Re: Sceptre X505BV-FMDR

    That is the connector of the LED string.
    What is the DCV rating of C8F, 9F?

    Sceptre AY160D-4HF06 Power Supply for X505BV-FMDR
    http://www.shopjimmy.com/sceptre-ay1...pply-unit.htm#
    Pictures provided by shopjimmy.
    Attached Files
    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

    • nwcs
      Badcaps Veteran
      • Dec 2015
      • 311
      • usa

      #62
      Re: Sceptre X505BV-FMDR

      I have same issue and have no voltage to leds at connector 10. All other voltages are fine. Same issue if I unplug the led connector. I would have to presume bad power supply.

      Comment

      • nwcs
        Badcaps Veteran
        • Dec 2015
        • 311
        • usa

        #63
        Re: Sceptre X505BV-FMDR

        Tested the led's and found one open led. Put in 1w 3.3v zener and now up and working. I guess 0v at the led connector does not mean a bad power supply.

        Comment

        • Force2recwith
          New Member
          • Sep 2016
          • 2
          • USA

          #64
          Re: Sceptre X505BV-FMDR

          I have the same tv, and having black screen with sound. Sorry if this question is ridiculous, but I'm not very tech savvy, would it be easier to purchase a new power supply, or try to replace the led bulbs as others have stated they have performed?

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #65
            Re: Sceptre X505BV-FMDR

            You need to at least be able to check the Voltages, it may be power supply or LED problem.
            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

            • nwcs
              Badcaps Veteran
              • Dec 2015
              • 311
              • usa

              #66
              Re: Sceptre X505BV-FMDR

              A good led tester would help. I found that the scepter tv's are deceptive and do not have any voltages or low voltages on the led inputs if there is a shorted led.

              Comment

              • Force2recwith
                New Member
                • Sep 2016
                • 2
                • USA

                #67
                Re: Sceptre X505BV-FMDR

                Is the led bulb most commonly needing changed out found on the main board/power supply?

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #68
                  Re: Sceptre X505BV-FMDR

                  Most common failure in the TV with LED backlights that no longer light up are due to bad LEDs, they drive them too hard so they failed like crazy.
                  The backlights level should be set to 75% or less from the maximum setting.
                  Replacing the LEDs are not the beginner either since you will have to take the LCD panel apart to get to the LEDs, that is why it is important to test the Voltages 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

                  • customer2042
                    New Member
                    • Jun 2018
                    • 6
                    • USA

                    #69
                    Re: Sceptre X505BV-FMDR

                    I have exactly same problem with the same Sceptre X50 TV as topicstarter reported on the first page. I found a bad LED in backlight strip and replaced it with 2835 LED as it was recommended in this thread. 100 LED's were found for $6 on eBay

                    I don't have low temperature soldering compound and used regular eutectic tin-lead 60/40 compound. Burned 3 LED's with practicing before learned a proper technique to solder them. 4th LED was successful and backlight was restored. I assembled TV back and it turned on as normal. However after about 3 minutes of running another random LED burned in backlight. I guess it will continue to burn if I keep replacing them.

                    Picture was not super-bright. But I didn't capture voltage when backlight was working. What should be normal voltage for backlight in this TV?

                    When backlight failed or disconnected, voltage jumps above 300V for a second after turning TV on and then drops down to zero. I believe it's normal (kind of protection of overvoltage) as mentioned by other participant of this thread.

                    Any ideas? What can be causing backlight LED's to burn so quickly?

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #70
                      Re: Sceptre X505BV-FMDR

                      Its the current that you need to check, LED's are current device, it they run at close to the limit, which is typical in most TV with LED backlights, they will burn up fast. What is the current rating of the replacement LED?
                      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

                      • customer2042
                        New Member
                        • Jun 2018
                        • 6
                        • USA

                        #71
                        Re: Sceptre X505BV-FMDR

                        Originally posted by budm
                        Its the current that you need to check, LED's are current device, it they run at close to the limit, which is typical in most TV with LED backlights, they will burn up fast. What is the current rating of the replacement LED?
                        20ma/3.4V front voltage max for replacement LED 2835

                        The problem is that random LED's burn in random BL strips, not a replacement LED

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #72
                          Re: Sceptre X505BV-FMDR

                          No way 20mA rating will last, they drive those LEDs in 300 ~ 400mA that is why they are 1W LED. So are you sure that it is rated at 20mA? that is awful low for even small white LED.
                          You should also look at the bottom side of the LED strip to see any over heated sign on each original LED.
                          Last edited by budm; 06-14-2018, 10:02 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

                          • customer2042
                            New Member
                            • Jun 2018
                            • 6
                            • USA

                            #73
                            Re: Sceptre X505BV-FMDR

                            Originally posted by budm
                            No way 20mA rating will last, they drive those LEDs in 300 ~ 400mA that is why they are 1W LED. So are you sure that it is rated at 20mA? that is awful low for even small white LED.
                            You should also look at the bottom side of the LED strip to see any over heated sign on each original LED.
                            Seller due20150801 on eBay where I purchases 2835 LED posted 20ma. Perhaps that was just current used to measure front voltage, not max ampreage. Other dastasheets found in Google show 80ma, 120ma and 240ma as max value.

                            It looks like max current very depends of manufacturer and not sure what is max on mine.

                            Interesting, how BadGoo (the name of author in one of postings on this thread) used 2835 LED for such repair of similar TV and they didn't burn?

                            Since I still have 96 of them for 6 cent a piece, I have temptation to hook one up to lab PSU and slowly increase current until it's fried. However the problem they are so tiny that it's hard to handle them and hook them up for testing
                            Last edited by customer2042; 06-14-2018, 10:26 PM.

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #74
                              Re: Sceptre X505BV-FMDR

                              The Vf is measured @ 20mA If. I wish they will put full spec on the page or the P/N.
                              Last edited by budm; 06-14-2018, 11:38 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

                              • customer2042
                                New Member
                                • Jun 2018
                                • 6
                                • USA

                                #75
                                Re: Sceptre X505BV-FMDR

                                Originally posted by budm
                                The Vf is measured @ 20mA If. I wish they will put full spec on the page or the P/N.
                                That explains...

                                I just asked that seller on eBay if he can give me a full datasheet or tell maximum current for those LED. Will look forward for his response

                                BTW, what is normal backlight voltage for Sceptre x505?

                                I don't remember exactly how many LED total there. It looks something about 60. So counting 60x2.4V should be about 144V total, shouldn't it?

                                How 300V peak at starting inverter wouldn't kill them unless 300V is just idle voltage?

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA

                                  #76
                                  Re: Sceptre X505BV-FMDR

                                  @300mA which is typical driving current, the Vf will be around 3 ~ 3.2V, the spec sheet will show the Vf VS If graph.
                                  The power supply for driving is the constant current power supply that will maintain constant current through the LEDs. The Voltage will vary to maintain constant current. The is Active element (MOSFET is typical) on the sink side of the LED string + the current sensing resistor for for feedback signal to the LED driver IC which sends PWM drive to the MOSFET.
                                  Look at the graph on page 10.
                                  If you get the P/N of the LED driver IC then you can look up the spec sheet and see the application notes circuit showing how the LEDs are driven.
                                  Attached Files
                                  Last edited by budm; 06-15-2018, 12:53 AM.
                                  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

                                  • customer2042
                                    New Member
                                    • Jun 2018
                                    • 6
                                    • USA

                                    #77
                                    Re: Sceptre X505BV-FMDR

                                    Originally posted by budm
                                    Its the current that you need to check, LED's are current device
                                    Since inverter keeps constant current for BL, not constant voltage, I just shorted out failed LED. Missing one of 70 - it's 1.42% drop in overall brightness and voltage. Not a big deal. Since it's between other (good) LED, behind diffuser and about 2 inch from LCD panel, darker spot is almost invisible on screen. As I understand electricity, it shouldn't make other LED work harder as current through them stays the same unlike in Christmas lights with shorted bulb

                                    However now I have a different problem. Screen has three vertical black stripes from the top to the bottom of it in random places. One about 3 inch wide, second about 2 inch and third about half inch. I guess I might accidentally damage LCD as it slightly wobbled in my hands when I disassembled TV to reach backlight. Is it fixable? If so, any ideas how?

                                    Comment

                                    • zape
                                      Senior Member
                                      • Jul 2017
                                      • 176
                                      • USA

                                      #78
                                      Re: Sceptre X505BV-FMDR

                                      Originally posted by Johnmoreno72
                                      Hi guys, Thank you so much for your help.
                                      To clarify, this is what I have: The red LED that should turn on when the TV is plugged to the wall is always off (there was a time weeks ago when I could make it come back ON by unplugging the TV for a few minutes but that's no longer the case) This is the same LED that should turn blue when I turn the TV ON, but that doesn't happen either (the TV does not turn on at all. Flashlight test also fails)

                                      As far as voltage levels on the PS board:
                                      +5V: 4.99V
                                      +12V: 12.34V
                                      +24V: 23.80V
                                      PS/ON: 4.42V
                                      +5VSB: 4.99V
                                      ADJ: 4.92V
                                      BL/ON: 0.06V (both with respect to DC GND and Chassis GND)

                                      There's also a small connector, called connector 10 (see pic, red/black wires) that reads -0.66VDC (with respect to each other, NOT with respect to CH GND or DC GND
                                      Having similar symptoms on a E485BV-FMQR
                                      I wonder if this is EEPROM or CPU
                                      CPU runs so hot so I burned my finger when touched it.

                                      Comment

                                      • ghcjr
                                        New Member
                                        • Aug 2018
                                        • 2
                                        • United States

                                        #79
                                        Re: Sceptre X505BV-FMDR

                                        Does anyone have Schematics?

                                        Comment

                                        • ghcjr
                                          New Member
                                          • Aug 2018
                                          • 2
                                          • United States

                                          #80
                                          Re: Sceptre X505BV-FMDR

                                          Can one of you describe the best way to get to the LEDs? Do I simply remove the screws around the parameter? Are there any other steps? I am fairly certain I have a blown LED.

                                          Comment

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