Announcement

Collapse
No announcement yet.

Panasonic LCD TV turns off after few seconds! HELP

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Panasonic LCD TV turns off after few seconds! HELP

    Hy,
    I want to fix Panasonic VIERA tx-l32c10p LCD TV. But I cant find out wich part is bad. I recorded the video of whats happening, but I will describe the problem anyway.

    1. When I turn tv on it turns on normaly, except the right side of display is darker than left side (this is not visible on the video).
    2. Tv then turns off by itself after few seconds.
    3. Red light starts blinking and it doesnt stop at all, except if I press any button on the remote (than it turns off and just blink i press any button on the remote).
    4. In order to turn TV back on I have to turn it off and on with master power swich.

    IF I QUICKLY PUT TV TO AV MODE (So there is no picture, except the AV sign) TV WONT SHUT OFF AND EVEN IF I OPEN MENU AND IT STILL WONT SHUT OFF. However if i plug in my digital converter TV will shut off after few seconds of showing picture

    The video:

    https://www.youtube.com/watch?v=NQlGGQWFCl8

    There is a picture of tv with back cover off in attachments.



    I tried to disconnect every single component one at a time to see if anything changes but no luck:
    -Because right side off the screen is darker and silent buzzing sound is coming out of two boxes on backlight circuit board (No.0) I tought that there is a problem with backlight or backlight circuit board (No.0).
    I disconnected 2 cables for backlights (No.1), but there was no difrience except display was not lighted.
    Than I disconnected whole backlight circuit board (No.2), but there was no difrience again.
    There is a blue LED on the backlight circuit board (No.3), there is a video of its activity!
    There is a picture of backlight board (No.0) in attachements!



    https://www.youtube.com/watch?v=rb3j4iCbRGs

    I also tried to connect No.1 left connector to socket for right connector and No.1 right connector to socket for left connector to see if display will be darker on left side instead on right side, but there was no change.

    I measured resistance of backlight (No.1) connectors and they are the same: 0,5 OHM!
    I also measured resictance of No.1 sockets and they are also the same: 0,3 OHM!

    -I tried to disconnect display board, speakers, board with buttons (i jumped the connector to turn tv on), LED and IR sensor board, but there is also no difrience.

    -I ofcourse also put tv to factory settings.

    I CANT FIND ANY BAD CAPACITORS, BAD CONTACTS, NOTHING FRIED UP OR ANY DAMAGE ON THE BOARDS AT ALL!!!

    There is SELF TEST info in the attachments -I found default resoults in service manual and confirmed that they are the same.




    I think that PSU is bad, but im not sure. What do you think?
    Attached Files

    #2
    Re: Panasonic LCD TV turns off after few seconds! HELP

    be careful when working with power supply, HIGH VOLTAGE, on primary side, can be deadly, start with checking everything labeled F on the boards, F=fuse, look m over real goods, they can be really small.
    Last edited by nomoresonys; 01-03-2015, 03:38 PM.

    Comment


      #3
      Re: Panasonic LCD TV turns off after few seconds! HELP

      Originally posted by nomoresonys View Post
      be careful when working with power supply, HIGH VOLTAGE, on primary side, can be deadly, start with checking everything labeled F on the boards, F=fuse, look m over real goods, they can be really small.
      Hy, thanks for your help. I will try do that. I will let you know if i find anything.

      Comment


        #4
        Re: Panasonic LCD TV turns off after few seconds! HELP

        Originally posted by kajaalyo View Post
        Hy, thanks for your help. I will try do that. I will let you know if i find anything.
        Hy again i found only one fuse marked as f101 and its OK! Do you have any idea what this could be?

        thanks

        Comment


          #5
          Re: Panasonic LCD TV turns off after few seconds! HELP

          cant see your backlight board very good, look it over real good, see if you can find a fuse to check.

          Comment


            #6
            Re: Panasonic LCD TV turns off after few seconds! HELP

            then I'd check power supply voltages, there should be a legend of expected voltages, right beside the pins where the connectors are.

            Comment


              #7
              Re: Panasonic LCD TV turns off after few seconds! HELP

              Originally posted by nomoresonys View Post
              then I'd check power supply voltages, there should be a legend of expected voltages, right beside the pins where the connectors are.
              Hy, i appreciate you help!
              I will try to locate fuse on backlight board! Voltages are not marked on board, but i found them in service manual!
              Do i need to look for voltage when disconected and powered on by shorting 2 contacts or do i need to look for voltage drop when tv turns off? Thanks

              Comment


                #8
                Re: Panasonic LCD TV turns off after few seconds! HELP

                Your first video, the picture looked brighter on the left side, that it is on the right side. Is that just on the video or really like that? Look at the voltages on the backlight driver board. There should be a few GND a few 24V, a BLON, a backlight adjust and may be an error line. For now check the 24V out and see if they disappear with the screen going blank.

                My guess is that it disappears. However, you can test your backlight, by disconnecting all other boards from the power supply, force the power supply on and just run the backlight. See if it keeps running.
                Last edited by CapLeaker; 01-04-2015, 06:26 AM.

                Comment


                  #9
                  Re: Panasonic LCD TV turns off after few seconds! HELP

                  Originally posted by CapLeaker View Post
                  Your first video, the picture looked brighter on the left side, that it is on the right side. Is that just on the video or really like that? Look at the voltages on the backlight driver board. There should be a few GND a few 24V, a BLON, a backlight adjust and may be an error line. For now check the 24V out and see if they disappear with the screen going blank.

                  My guess is that it disappears. However, you can test your backlight, by disconnecting all other boards from the power supply, force the power supply on and just run the backlight. See if it keeps running.
                  If you stand in front of the TV picture is darker on right side. BLON is pin that i need to short out to turn PSU on or i need to measure voltage from it, if so what should be the voltage?

                  If voltage disappears this is bad PSU than?
                  I will also try to test backlights like you tell me!

                  I will let you know about resoults!

                  Thank you.

                  Comment


                    #10
                    Re: Panasonic LCD TV turns off after few seconds! HELP

                    this could be a capacitor issue, they dont have to bulge to be bad, could also be a prob. with mainboard.

                    Comment


                      #11
                      Re: Panasonic LCD TV turns off after few seconds! HELP

                      I think you jumper stby to bl-on, someone correct me if I'm wrong, not exactly sure.

                      Comment


                        #12
                        Re: Panasonic LCD TV turns off after few seconds! HELP

                        Originally posted by nomoresonys View Post
                        I think you jumper stby to bl-on, someone correct me if I'm wrong, not exactly sure.


                        This is wiring diagram, i marked the connector with green circle. I dont get it, i must connect STBY_5V6 to what? thank you!
                        Attached Files

                        Comment


                          #13
                          Re: Panasonic LCD TV turns off after few seconds! HELP

                          https://www.badcaps.net/forum/showthread.php?t=17997 heres a good post, #5 describes the jumper a little, it is from stby to ps-on.

                          Comment


                            #14
                            Re: Panasonic LCD TV turns off after few seconds! HELP

                            Originally posted by nomoresonys View Post
                            https://www.badcaps.net/forum/showthread.php?t=17997 heres a good post, #5 describes the jumper a little, it is from stby to ps-on.
                            Mine does not have ps-on connection, so i must connect stby to something else, maybe relay?

                            Comment


                              #15
                              Re: Panasonic LCD TV turns off after few seconds! HELP

                              Originally posted by kajaalyo View Post


                              This is wiring diagram, i marked the connector with green circle. I dont get it, i must connect STBY_5V6 to what? thank you!
                              I dont see ps-on, I cant figure it out ether.

                              Comment


                                #16
                                Re: Panasonic LCD TV turns off after few seconds! HELP

                                Originally posted by nomoresonys View Post
                                I dont see ps-on, I cant figure it out ether.
                                :S I tried to connect relay to stby but nothing happends :S

                                Comment


                                  #17
                                  Re: Panasonic LCD TV turns off after few seconds! HELP

                                  Originally posted by kajaalyo View Post
                                  :S I tried to connect relay to stby but nothing happends :S
                                  maybe wait for some better guidance, you dont want to short anything out.

                                  Comment


                                    #18
                                    Re: Panasonic LCD TV turns off after few seconds! HELP

                                    Originally posted by nomoresonys View Post
                                    maybe wait for some better guidance, you dont want to short anything out.
                                    No worries, first i powered tv on and test resistance between these two connections, I found that resistance is 0. Than i tried to connect those two without motherboard!

                                    Comment


                                      #19
                                      Re: Panasonic LCD TV turns off after few seconds! HELP

                                      Originally posted by kajaalyo View Post
                                      No worries, first i powered tv on and test resistance between these two connections, I found that resistance is 0. Than i tried to connect those two without motherboard!
                                      Ok i figured it out. There is another connection TV_SUB_ON_RELAY_ON in order to turn psu on i connected TV_SUB_ON_RELAY_ON with RELAY_5V6 and STBY_5V6,
                                      Now i can hear relay click when i plug corn in, but nothing shows up :S



                                      Here you can see (left red circle) that there are some ..._ON connections for backlight board, do i need to connect those to something as well? Right circle is that TV_SUB_ON_RELAY_ON that i found.
                                      Attached Files

                                      Comment


                                        #20
                                        Re: Panasonic LCD TV turns off after few seconds! HELP

                                        You also need to jumper the backlight on to the 5v standby to force it on

                                        Comment

                                        Working...
                                        X