Why?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • capwizard
    Badcaps Legend
    • Jun 2016
    • 1991
    • USA

    #1

    Why?

    This Hitachi LB55061 I changed LED, when I took pictures show the dark bars but not in my vision? Is something does with LED PWM blinking frequency? How can I calculate it out (camera at 1080p)?

    Last pic: Took with no backlight. I dont thing so, because is in the pic..

    Is something do with this?
    Attached Files
    Last edited by capwizard; 02-14-2017, 03:33 PM.
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Why?

    Its your camera shutter speed and PWM.
    http://www.tftcentral.co.uk/articles...modulation.htm
    http://laptopmedia.com/highlights/wh...o-our-reviews/
    Last edited by budm; 02-14-2017, 08:00 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

    • capwizard
      Badcaps Legend
      • Jun 2016
      • 1991
      • USA

      #3
      Re: Why?

      "We can infer that the phosphor involved in producing blue can switch both on and off faster than the other colours. the backlight will continue to emit light for a few milliseconds after the backlight power is switched off at the end of a duty cycle, "

      I saw this phenomenon, I don't think anybody can answer my question, No one will pay attention to it. budm, Thank you. Your correct answer is really surprised me!.............

      PS: For 20 minutes I can't find my (T-mobile LG stylo 2 plus) shutter speed, so I use Meter test the frequency of the PWM to LED, found is 20 kHz. 20.000/5 bars = 4000

      "Multiply this count by the inverse of the shutter speed. For example, if using a shutter speed of 1/25 of a second and 7 cycles are counted, then the number of cycles per second is 25 * 7 = 175Hz. This is the backlight cycle frequency."

      4000 * 5= 20000 =20 kHz ...........So, 1/4000s that is the shutter speed of my phone. ........
      Attached Files
      Last edited by capwizard; 02-15-2017, 07:56 AM.

      Comment

      • madan1
        Badcaps Veteran
        • Nov 2016
        • 670
        • Bulgaria

        #4
        Re: Why?

        check the metadata of the original photos.. there will find the shutter speed

        Comment

        • capwizard
          Badcaps Legend
          • Jun 2016
          • 1991
          • USA

          #5
          Re: Why?

          But ...but ...Before you say "Common on, get outta here!"...I have A question?... Why is horizontal bars instead of vertical?
          Last edited by capwizard; 02-15-2017, 09:41 AM.

          Comment

          • madan1
            Badcaps Veteran
            • Nov 2016
            • 670
            • Bulgaria

            #6
            Re: Why?

            try tilting the camera.. if the lines stay horizontal, then its because the camera sensor is scanned line by line.
            Check here similar effect https://www.youtube.com/watch?v=R-IVw8OKjvQ ( just to note that it's not like the russians have implemented some extraterrestrial technology in their choppers )
            Last edited by madan1; 02-15-2017, 09:50 AM.

            Comment

            • capwizard
              Badcaps Legend
              • Jun 2016
              • 1991
              • USA

              #7
              Re: Why?

              AH-64 Apache or Mi-24 is better? Why I ask this? I tell you a big military secret, Apache is build over here, Mesa, Arizona.
              Last edited by capwizard; 02-15-2017, 11:10 AM.

              Comment

              • Dadiuskilius
                Dead inside
                • Jun 2017
                • 2
                • USA

                #8
                Smd led

                Will you please share type/ratings of LED you had success with on the LB55061 strip?

                Comment

                • stj
                  Great Sage 齊天大聖
                  • Dec 2009
                  • 30937
                  • Albion

                  #9
                  Re: Why?

                  mi24 was better - now discontinued though.
                  bigger, faster, stronger armor, larger payload.

                  replaced by 3 seperate models,
                  when you need something big & heavy that can take fire: MI-35
                  http://www.russianhelicopters.aero/e...ry/mi-35m.html

                  small attack: MI-28
                  http://www.russianhelicopters.aero/e...ry/mi-28n.html

                  super fast nightmare class :KA-52
                  http://www.russianhelicopters.aero/e...ary/ka-52.html
                  Last edited by stj; 06-24-2017, 02:58 AM.

                  Comment

                  Related Topics

                  Collapse

                  • Akira81
                    LG 55LF652V-ZA flashing led bars despite their replacement
                    by Akira81
                    Hello everyone,

                    I have this 55" LG 55LF652V-ZA smart TV which suddenly started flashing intermittently every 2 seconds with the backlight.



                    If I aimed the light bulb of my cell phone I could see the underlying image even in those fractions of time when the LEDs were off and the audio instead came out continuously.

                    Armed with a lot of space and patience, I decided to open the TV, immediately noticing that a LED had flamed out and also burned a portion of that reflective white panel behind the transparent LED diffusers.
                    ...
                    04-14-2023, 11:50 AM
                  • lilfarhad94
                    Fujifilm X-T20 Shutter Issue
                    by lilfarhad94
                    Hi all,

                    I have a Fujifilm X-T20, and the shutter is not working. The camera seems to think the aperture is stuck and gives me an error message asking me to turn it off and on again (Turn off the camera and turn on again).

                    I noticed that there are two optical sensors near the shutter. Each sensor has four pins, with two of them connected together, meaning there are only three wires per sensor going to the mainboard. None of these wires are connected to ground.

                    When measuring the voltages during operation, I found the following values:

                    - Sensor...
                    02-08-2025, 10:29 PM
                  • x_orange90_x
                    Samsung UN46C8000XFXZA vertical bars/horizontal lines
                    by x_orange90_x
                    I posted about this previously but didn't get any response, and I have some troubleshooted a bit so I have more info.

                    The screen is full of horizontal "gaps" or lines that distort the picture badly, and after about 10 seconds of powering it on the screen starts to fill with red vertical bars that take on the horizontal pattern. After the screen filled with the red bars, they instantly vanished and then slowly started to reappear. I initially thought it was tab bonding failure, but after getting down to them and pressing each one I find zero change in the picture. I went...
                    09-04-2023, 12:09 PM
                  • CapLeaker
                    LG 65UQ70 horizontal bars jumping
                    by CapLeaker
                    So I bought this LG 65UQ70 today at Walliworld. Put the wall mount on, set it up, worked for 30 mins and then I get these jumping horizontal bars. Let the TV do updates and let it cool down for 5 mins. Worked perfect for 2 mins. As soon the TV is warm I get the jumping vertical bars again.

                    Keep the other TCL thread in mind. Now I am questioning are all COVID 2022 / 23 TV’s bad or what? That’s two 65” TV’s one from Amazon and this one from Walmart. What are the chances on that?

                    I guess this one goes back either later today or tomorrow morning, unless...
                    08-13-2024, 09:41 AM
                  • ninja_zx11
                    Sharp LC-70LE650U vertical black and red bars
                    by ninja_zx11
                    Hi all,

                    70" LED TV is Sharp LC-70LE650U.

                    Initial problem was horizontal lines and slow motion lurrs on the bottom left of the screen. So I removed both the left and right ribbon cables from the T-con board and tried to clean it with alcohol and when I put it back, this issue appeared. I tried carefully reinserting the ribbon bon cables but same thing. I checked the traces of the ribbon cables with magnifying glass and everything looks good. I cleaned the small jumper ribbon cable on the left side of the screen which cured the horizontal line and slow motion blurs...
                    07-07-2023, 11:27 PM
                  • Loading...
                  • No more items.
                  Working...