LG 55ec9300-UA No Picture, No Sound, no 5vUSB

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • rhinomods
    New Member
    • May 2013
    • 2
    • USA

    #1

    LG 55ec9300-UA No Picture, No Sound, no 5vUSB

    Howdy,
    I have gone through the forums and tried a bunch of things that others had posted. I am hoping some one can point me into the right direction.

    Original symptoms.
    press the power button you can hear the relay click.
    The LG logo illuminates white for a moment then fades out.

    Behind the back cover.
    when Power button is pressed the red LED on the Main/Media board stays illuminated.
    You can not turn the tv off with the power button. when using IR remote You hear the relay click OFF and the Red LED is no longer lit.
    There is NO 5v Going to USB ports, NO SOUND NO PICTURE.
    Main/Mediaboard
    Powersupply
    Tcon Side a
    Tcon Side b

    First test

    Followed directions of LG Smps Testing. BOTH "1" and "2" parts of the testing were followed.
    All voltages are present. 3.3v 12v 24v
    Tested 24Volts with Bulb and it tested ok.

    On the post by Diah he says to supply 12v from power board socket to T-con F1 fuse (I don't have F1 fuse but in the same spot there is "F71")
    by doing his steps. plugin in mains Power on the TV a moment later it goes automatically into panel test colors.. This was Brilliant Bright perfect colors no display damage or Distortion on the panel.)
    video of the Test Pattern on the panel.https://photos.app.goo.gl/JVpnKvjJFn2nKPvK9

    I let this run for about 5- 10 min Feeling like there was a mild victory.

    Second test
    Unplugged mains, removed jumpers from 1st voltage and test pattern. plugged in the TV and powered on The set continued to behave with original symptoms.

    unplugged mains, removed 2 center ribbon cables to the panel from the T-Con board ( can not find which post recommended this test.)
    Plugged in and powered on. Relay clicks on Flash of white at top of panel (about 1 inch) USB gets ~5v for less than 1 second. Red LED on Main/media board. a short moment later Relay clicks off.
    doing this a few times Locks the Main/Media board out.

    I continued to reattach the Panel Ribbon cables to the T-Con board
    Supply mains power. Power on TV. Relay clicks on. LG Logo illuminates white for a moment. Usb 5V < 1second Red Led on Main/Media board Relay clicks off. Mainboard LED off.

    Third Test
    Attempted IR service remote zip file supplied from Freakafter8

    Both on a Android that has IR blaster. and even built a IR blaster with Headphone jack and used the media files on both a laptop and android device full power Pitch-black room.

    "Power only" Never turns the TV on. THE IR blaster on the android is working with universal remote apps,
    Found 2 different service remotes under "IRplus" and "Smart Remote" Applications. The TV will respond to power button but not "power_only" "in-start" or "in-stop"

    I followed a post about holding down sw201 on the main board. press power button. wait for 3 relay clicks (4 if you include the first power on click)
    Pressed power button on remote. Relay clicked off.
    pressed power button on remote. Relay clicks on. Symptom 1 returns. ( no longer locked?) the red LED stays on until power button on IR is pressed and the relay clicks off.

    Any Ideas on where to go now?
    Thanks for everyone's support on Badcaps.net
    This has been and extremely useful site for me!
    Hopefully this is not too difficult to understand.

    Rhino

Related Topics

Collapse

  • thstuff
    Sony OLED XR-77A80J - Initially dead, now 4 Flashes
    by thstuff
    A) TV initially dead
    B) On a hunch of a locked up Google OS, plugged in a USB memory stick with latest FW and plugged it in. It booted into the update screen, completed the update and restarted to Home screen.
    C) Was able to perform a Reset from Settings menu and completed out of box configuration.
    D) Ran a 4K screen saver demo for about 6 hours, then turned it off for the day. Did not notice any stripes, dead zones or other artifacts in the image.
    E) Powered back on and it now runs for a few minutes before relay clicks, screen goes blank, Main Board Red Digital Optical...
    12-26-2024, 09:10 PM
  • Rensiee
    Panasonic TH-50PX8EA Black screen, only relay clicks
    by Rensiee
    Hello,
    I have been reading a few threads on here regarding Panasonic plasma tv's. I've found one thread which explains the same problem as mine, unfortunately the thread has not been completed.
    I got a free tv (TH-50PX8EA) from a friend which shows no screen. When plugged in only one red light shows up and when pushing the ON button, the red LED turns of and will only turn on again when pressing the ON button again.

    When plugging in the TV i hear two relays click fast and after a few seconds the third relay clicks.
    I have measured the voltage in the VSUS line, which...
    06-18-2024, 12:58 PM
  • TrisHCl
    LED TV Boot loop - UE40F6500SB
    by TrisHCl
    Hi,

    First post...

    I have this TV, which was working, then suddenly would not turn on. It would get the clicking relay then flash up the screen for less than a second, off for a second then on again. Removing the plug the relay continues to click on and off for a few cycles, which I don't think it did before.

    Left it a few months, then finally got round to taking the back off, and it worked as it should. So I tested various bits and all was well. Then turned it on again, and back to the clicking relay.

    I disconnected the main board from the power...
    02-06-2025, 08:42 AM
  • samtron786
    toshiba 46xv555d relay clicks
    by samtron786
    Hello
    The red and green LEDs both light up and you can hear the relay click. (no picture, no backlight, no sound)
    2-3 seconds later the relay will click again and only the red LED will stay on.

    I would be very grateful for any advice or a little help.
    circuit diagram?


    Thanks very much
    02-04-2023, 04:39 PM
  • chth96
    How Can I test PWM DM0365R?
    by chth96
    Hello
    I have power adaptor(220V/input, 12V 1.2A/output) which has symptom of fluctuating output DC voltage between 11.5V-12.2V.
    So I opened its plastic case and when switched it on, I heard constant tik tik sound from inside its PCB.
    I measured DC voltage between negative and positive pin of the largest capacitor(400v 10uf) and it was measured contant 300V.
    I also measured ESR value of all capacitors and I noticed that one of capacitor(KMG 16v 470uf), which located in the secondary side, have high ESR value(10 ohm),So I replaced it with same specification NXH capacitor....
    06-18-2025, 04:14 PM
  • Loading...
  • No more items.
Working...