Samsung LNT4069FX no picture with sound

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • thehutman
    New Member
    • Aug 2011
    • 2

    #1

    Samsung LNT4069FX no picture with sound

    Hi all! First post here, and I'm hoping you can help me. This site is great, and it's gotten me 50% of the way there already

    Now my issue. I'm the owner of a Samsung LNT4069FX 40” LCD television. A few weeks ago, the TV started having power-on problems. I didn't see it myself, but my wife began the initial complaints (isn't that how it always goes). Once the weekend hit, I got up in the morning to find the TV exhibiting the clicking power-cycle problem. Power on the set, the power LED blinks and your hear the relay clicking on and off. No picture ever came up.

    After doing some investigation, I found a lot of articles on Samsung caps going bad. So, later that day I took off the back of the set and looked at the power board to find one, maybe two (hard to tell since they were so close together) bad caps with the leaking electrolyte brown fluid between them. The fluid was wet and sticky, so seemed fairly recent and not dried up.

    Got online and ordered some new caps to replace all of my 1000uf and one 220uf caps. Got a set of Nichion's and replaced all 1000uf and the one 220uf cap last weekend. I found one other bad cap I didn't notice the first time, so I think I had two bad caps, with maybe a third looking suspect. After the re-capping, the set powered right up afterwards! Hooray!

    BUT (there's always a but)

    After a day of working fine, the TV is now doing something even weirder. It powers on, but you get NO picture. There IS sound. Odd. I can change the volume, but no OSD would show. As I was playing around with the remote, I noticed what appears to be the backlights slowing coming on … starting in the center of the screen with a vertical pattern and moving towards the outer left/right edges. After about a minute the screen backlight would cover the whole screen. I powered off the set, turned it right back on, and BINGO, I have picture and everything works fine.

    If I let the set sit for an hour or two, it cools off and I'm back into no picture on power-up. Wait for the backlights to come up to speed and then it is fine. If I power cycle it too soon before it has warmed up, I still get no picture. It takes only a minute for the set to warm up enough apparently based on how its been working for the past few days.

    So, what should I be looking for? Saw some mention on another thread about the inverter board and transformers, but I don't recall there being any on my model (transformers on the inverter board that is). I intend on opening it up again once I can get it away from the wife and kids and getting some pics of the boards … but I hoped that some of this might spark some ideas on what I can look for (if anything).

    Thanks for any and all advice you may have!

    Regards,

    Mike
  • LITEZONER
    GO BOLTS!
    • Mar 2010
    • 223
    • USA

    #2
    Re: Samsung LNT4069FX no picture with sound

    I am no expert here, But I have managed to fix a couple of TV's with similar symptoms, with the exception that I think yours is haunted! The TV has a T-Con board, it is Basically the video brain. on that board, well at least the one's I fixed there were some capacitors that had loose solder joints, and in one case there was a tiny almost micro fuse that had an open circuit. I suspect that you have a loose solder joint somewhere, that when it heats up and expands you are loosing contact with a critical component IE fuse, or Cap, I know of no other way to check these other than to run an iron over then and re melt the connections, Just my two cents.
    39 Soldering Iron burns And Counting

    Comment

    • RON_CET
      Badcaps Veteran
      • Jun 2012
      • 217
      • USA

      #3
      Re: Samsung LNT4069FX no picture with sound

      make sure all the caps that have vented @ top or domed have been changed? here's something to check by
      Attached Files
      Ron Driver,BSEE,CET,ISCET,NESDA

      Comment

      • ceconomon
        Senior Member
        • Oct 2011
        • 67
        • USA

        #4
        Re: Samsung LNT4069FX no picture with sound

        Mike,
        Were you ever able to resolve this issue? My parents have the same model with the exact problem you described. They were able to get picture on it after letting it warm up and power cycling it. It's no longer falling for that trick and now they can just listen to the TV.

        The power board has been re-capped and the t-con board replaced.

        Carson

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Samsung LNT4069FX no picture with sound

          Do you get 24VDC to the backlights inverter board? Pictures of the boards will be big help.
          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

          Related Topics

          Collapse

          • TR103
            Samsung TV model UE50TU: rebooting, backlight, sound, but no picture
            by TR103
            Hi, I have a Samsung UE50TU with:
            - sound and backlight, but no picture
            - when it arrived, it had a picture for a few seconds
            - it keeps rebooting
            - without ribbon cable between the two panel boards, it does not reboot but I have no picture
            - without cable between mainboard and lcd panel, it does not reboot (but obviously i have no picture)
            - when i try a tape fix, its keeps rebooting, unless I tape off pin 1 (the innermost pin). In that case it does not reboot but I have no picture.

            - without cable between mainboard and lcd panel and with a jumpered...
            01-22-2025, 04:12 PM
          • Mgiffune
            Samsung UN60EH6000F Black Screen, Backlight and Sound Good. Power Cycle Returns Picture
            by Mgiffune
            I have a 60 inch Samsung UN60EH6000F flatscreen TV. The screen went black a few months ago Sound is good, backlight is good, no menu. I replaced the TCon board with a used board purchased from Ebay. It worked fine for a 3-4 months, then the screen started ‘fading' back. Once again, sound is good, backlight is good, no menu. However, this time the picture looks fine for about 10-15 minutes, then fades back. If I power cycle the TV, the display reappears, for another 10-15 minutes, then fades black again. Repeatable ever time.

            I ordered a supposedly ‘new' Tcon board this time, and
            ...
            06-09-2024, 10:28 AM
          • Ierwin
            Samsung UE60KU6079 backlight okay mainboard responsive, no picture, no sound
            by Ierwin
            Hello everyone,
            Ive got a UE60KU6079 on the workbench that is giving me some headaches trying to troubleshoot.
            The previous owner stated that there had been white dots on the screen which from the description sounded like some lenses fell of the backlight LEDs.
            He had opened the TV from the back, trying to get to the backlight, supposedly gave up, reassebled everything and gave the TV to me.
            I expected the worst like ripped COF cables or a cracked panel but could not find anything like that yet.
            Anyway I still fully expect that there has been something seriously damaged...
            05-13-2025, 03:31 PM
          • jchang
            Samsung UN70NU6900F no picture and no sound
            by jchang
            Hi all

            I was just given a Samsung TV with the issue. I read various threads and videos and attempted the ribbon tape method to gain an image, but no luck.



            Symptom:
            No picture no sound.
            When I plug in the power cord, Backlight LED turns on for a half second and then turns off. The red LED next to the power button located center bottom flashes 2 or 3 times. When the power button is pressed after, it does the same thing.
            No sound at all.



            What I tried:
            1. I tried unplugging the left or right ribbon...
            01-09-2023, 06:28 PM
          • Dodgethis
            Samsung QN75Q6DRA, No Picture, Has BL, and Sound
            by Dodgethis
            Hello all,

            This is my first post, but long term lurker on the form learning as much as possible about these TV's. I was given this TV as due to a power outage of constant On/off of power to TV. The TV originally would just click on and off (Typical Reboot Cycle). I opened the back of the TV, and troubleshooted by taking the 96 pin LVDS off one at a time to see if I had a picture on either side. I finally fixed the reboot cycle by finding the error on the left side of the screen off connector CN 1301, and the TV would stay on. Further troubleshooting led me to the driver boards where...
            09-11-2024, 07:39 AM
          • Loading...
          • No more items.
          Working...