Sony XBR-65x900F troubleshooting unresponsive TV

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  • yavqq
    New Member
    • Feb 2023
    • 4
    • US

    #1

    Sony XBR-65x900F troubleshooting unresponsive TV

    Hello everyone,

    This all started a few days ago when out of no where the TV appeared unresponsive. Pushing the power button did not do anything and there was no standby light active. However, holding the power and volume up button while plugging in the AC power did show a steady solid green light. Still no display and no further activity from there.

    After some research I did some measuring of the common voltage points..

    Main Board Connector
    Pin 02 "BL_ON": 0.00V
    Pin 03 "POWER_ON": 3.47V
    Pin 05 "STBY 3.3V": 3.50V
    Pin 26 "TCON_ON": 0.00V

    After noticing the power_on and STBY are 3.5V I'm assuming the power board is okay. Since BL_ON and TCON_ON have no voltage led me to believe this could be the mainboard since research showed this signal comes from the mainboard.

    I tried re-sitting all of the mainboard cables with no luck. But after removing all of the cables and only connecting the power -> mainboard and plugging in the power cord I noticed some more light activity on the LED driver board which was a good sign.

    I unplugged the power cord and plugged back in all of the connections and low and behold the TV started up normally with working screen and sound! I didn't think much of this and figured could have been a loose cable somewhere.

    Since then I've had the TV on maybe 30 minutes or so but not streaming or watching anything and everything seemed fine. Finally decided to watch a movie and about 10-15 minutes in some horizontal black bands and lines appeared for 5 seconds or so before finally the image freezes on a previous frame but no longer any horizontal lines. There was still sound but just a frozen picture.

    After unplugging the power we were back to step one. The TV is now unresponsive again with the power button not doing anything and resetting the power also does nothing.

    My first guess was this could be a mainboard issue maybe the EMMC chip but since the TV briefly worked for a short time this had me confused.

    Any ideas what could be going on here? I'm unsure if this could be the mainboard or maybe the TCON board. Is there any other voltage tests I can take to narrow the problem. I don't necessarily have the gear to jump any pins but again the brief time the TV was working makes me think the backlight and LCD are okay.

    Thanks
  • nomoresonys
    Badcaps Legend
    • Jan 2013
    • 12137
    • U.S.

    #2
    Re: Sony XBR-65x900F troubleshooting unresponsive TV

    heat the tcon board with a hairdryer for a couple minutes and retry the tv, don't wait til it cools down, try it while its still hot, see if theres any change.

    Comment

    • yavqq
      New Member
      • Feb 2023
      • 4
      • US

      #3
      Re: Sony XBR-65x900F troubleshooting unresponsive TV

      I have not tried the hairdryer on the tcon board yet.

      After leaving the TV unplugged for about 24 hours, the TV started up and displayed the Sony logo then a black screen. The standby light is on and displaying a white color.

      The power button does not seem to turn off the TV at this point. The standby light does flash a brighter white when issuing commands via the remote.

      Comment

      • Davi.p
        Hobbist Tech
        • Sep 2009
        • 4314
        • Italy - Milan

        #4
        Re: Sony XBR-65x900F troubleshooting unresponsive TV

        I think much probably CPU has soldering problems..

        Comment

        • yavqq
          New Member
          • Feb 2023
          • 4
          • US

          #5
          Re: Sony XBR-65x900F troubleshooting unresponsive TV

          Update to this thread.

          I ended up replacing the main board. After updating the software with a USB the TV was up and working again.

          I'm assuming this was some sort of solder problem like previously mentioned.

          Thanks everyone for the help.

          Comment

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