Polaroid P50D300S No picture

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  • unxtres
    Member
    • Aug 2017
    • 20
    • United Kingdom

    #1

    Polaroid P50D300S No picture

    Black screen, there is sound and reaction for remote, backlight is also on
    I`ve tried to change T-Con but same issue
    Voltages on main and Psu are present there is also 12v on fuse on tcon
    any ideas?

    TV - Polaroid P50D300S
    Screen - VES500UNDA-2D-N11
    T-CON - T420HVN06.3
    MAIN - 17MB97
    PSU - Vestel 17IPS12
  • dskall
    Badcaps Legend
    • Oct 2016
    • 2905
    • usa

    #2
    Re: Polaroid P50D300S No picture

    You got anything on your data lines to t-con? If you unplug one ribbon cable at a time going to panel what do you get?
    I assume no responsibility for any stupid suggestions I might post.

    Comment

    • unxtres
      Member
      • Aug 2017
      • 20
      • United Kingdom

      #3
      Re: Polaroid P50D300S No picture

      nothing, screen are still black, no, lines nothing, i have also checked caps on screen electronics for shorts but everything looks good, this tv is like ghost

      Comment

      • dick_barton
        Badcaps Legend
        • Aug 2015
        • 6642
        • Wales

        #4
        Re: Polaroid P50D300S No picture

        Have you checked that you have a supply voltage to the tcon?


        Edit
        Oops, I see you have already checked.
        Last edited by dick_barton; 08-11-2017, 02:52 PM.
        Willing to help but I'm no expert.

        Comment

        • unxtres
          Member
          • Aug 2017
          • 20
          • United Kingdom

          #5
          Re: Polaroid P50D300S No picture

          Originally posted by dick_barton
          Have you checked that you have a supply voltage to the tcon?


          Edit
          Oops, I see you have already checked.
          Yes and fuse are ok too, no shorts on ceramic caps

          Big IC on t-con also getting to be warm when tv is on

          Possibly firmware fault but i still i can change source (blindly) and there is sound in speakers.

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: Polaroid P50D300S No picture

            If you have a scope you can check LVDS lines for activity.

            One "hack" is to try partially disconnecting LVDS cable and seeing if you get patterns on the screen. I wouldn't do this too much, but a brief check to see if the panel is working at all may be helpful.

            My bet would be a bad panel.

            If you have an RS232 to USB adapter and some wires there's a way to get a debug port on the SCART port of the TV, this will let you log in to the operating system of the TV to have a fiddle with some settings or test modes.
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

            Comment

            • unxtres
              Member
              • Aug 2017
              • 20
              • United Kingdom

              #7
              Re: Polaroid P50D300S No picture

              tom66 looks like bad panel, tried disconect ribbon conections and there is nothing on screen, looks like dead.

              Im interested in this RS232 can you provide me some links or more info about it

              Comment

              • tom66
                EVs Rule
                • Apr 2011
                • 32560
                • UK

                #8
                Re: Polaroid P50D300S No picture

                What's the motherboard model number? 17MBxx
                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                Comment

                • unxtres
                  Member
                  • Aug 2017
                  • 20
                  • United Kingdom

                  #9
                  Re: Polaroid P50D300S No picture

                  17mb97

                  Comment

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #10
                    Re: Polaroid P50D300S No picture

                    Right... Can't find exact schematic but quick look shows same as other boards across the range.

                    You will need a USB to RS232 cable that accepts low voltage levels...MOST do, but some do not. If you do not have one then use this. NOTE most PC RS232 sockets will *not* work as they require the +/-10V logic levels that the TV will not use.

                    If you do not have one then use one of these:
                    http://www.ebay.co.uk/itm/2Pcs-Ardui...kAAOSw3lFZeGMf

                    I will assume you are using Windows.

                    First use software like PuTTY (https://www.chiark.greenend.org.uk/~...ty/latest.html) to use the serial port.

                    Enter your COM port number (you can find it in Device Manager on Windows) and baud rate 115200.

                    Tie the transmit and receive (TX and RX) of your cable/connector together. Then type. If characters are seen in PuTTY, your cable is working and set up correctly. (This is an echo test.) Note characters do not normally appear unless "echoed" by the receiver, therefore do not expect anything to appear when the cables are disconnected if you type.

                    Then you will want to connect the TX of your device to the RX of the TV, and RX to the TX of the TV. It is pin 12 that is the TV's transmit (TX) and pin 14 that is the TV's receive (RX). See this diagram for SCART pinout. (Note Vestel use the spare pins for the port.)

                    http://www.leadsdirect.co.uk/wp-cont.../scartdiag.gif

                    If all is well, when you turn on the TV, you will get a load of debug output. This may tell you if there is a problem in a specific area, for example unable to read a certain file which may be fixable via firmware update.

                    It should also prompt you to press a key to enter a terminal, which should let you enter the Linux operating system. If a password is requested, try "314159".
                    Last edited by tom66; 08-11-2017, 03:20 PM.
                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                    Comment

                    • unxtres
                      Member
                      • Aug 2017
                      • 20
                      • United Kingdom

                      #11
                      Re: Polaroid P50D300S No picture

                      Thanks Tom that may be useful in future

                      Anyway i found that for this board 17mb97 RX are pin 10 and TX - 12
                      i need also to connect gnd to pin 14
                      i`ve got some strange output:

                      ▒/y▒▒L▒{▒▒f▒▒5▒n▒▒▒▒cvr▒▒▒▒▒▒,▒w▒▒▒h▒▒a▒q▒a8▒=▒t▒▒▒cS▒y▒▒▒▒▒w▒▒▒w▒M▒u▒▒W▒▒$▒5▒+Z▒x▒S▒▒▒▒j▒4▒▒▒▒▒▒▒▒▒▒sf▒▒▒▒▒oq▒ާsw|P▒cŵ▒▒#c▒m▒▒?-

                      i have uploaded service manual for that board.
                      Attached Files

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #12
                        Re: Polaroid P50D300S No picture

                        You might need to experiment with different baud rates, 9600, 19200, 115200 and 230400 are commonly used; the series basically doubles between each value. You would need a scope to measure the bit period to know the exact baud rate.
                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                        Comment

                        • unxtres
                          Member
                          • Aug 2017
                          • 20
                          • United Kingdom

                          #13
                          Re: Polaroid P50D300S No picture

                          i`ve tried different baud rates with highest value than 9600 ive got more data back but it is still unreadable :/

                          Comment

                          • dick_barton
                            Badcaps Legend
                            • Aug 2015
                            • 6642
                            • Wales

                            #14
                            Re: Polaroid P50D300S No picture

                            If the service manual is the one for your mainboard then it looks like the connections will be:-

                            SCART Pin 10 = UART Rx (Received data)
                            SCART Pin 12 = UART Tx (Transmitted data)
                            SCART Pin 14 = Ground

                            From page 58
                            Willing to help but I'm no expert.

                            Comment

                            • unxtres
                              Member
                              • Aug 2017
                              • 20
                              • United Kingdom

                              #15
                              Re: Polaroid P50D300S No picture

                              Originally posted by dick_barton
                              If the service manual is the one for your mainboard then it looks like the connections will be:-

                              SCART Pin 10 = UART Rx (Received data)
                              SCART Pin 12 = UART Tx (Transmitted data)
                              SCART Pin 14 = Ground

                              From page 58
                              Yes it is connected in that way

                              Comment

                              • dick_barton
                                Badcaps Legend
                                • Aug 2015
                                • 6642
                                • Wales

                                #16
                                Re: Polaroid P50D300S No picture

                                Do as Tom suggested and disconnect the Tx and Rx wires from the SCART connector and short them together.
                                Run the Terminal program and set the baud rate and echo character.
                                Whatever you type should now reappear on the computer screen so if you typed "a" then "aa" should show on the screen.
                                Once you have that, you can then disconnect the wires and reconnect them to the SCART inputs. You may have to swap the two wires over.
                                Last edited by dick_barton; 08-11-2017, 05:21 PM.
                                Willing to help but I'm no expert.

                                Comment

                                • unxtres
                                  Member
                                  • Aug 2017
                                  • 20
                                  • United Kingdom

                                  #17
                                  Re: Polaroid P50D300S No picture

                                  dick_barton i receiving data from tv this is not issue with non working rs232.
                                  as i mentioned several posts ago,

                                  data that i receiving are not readable

                                  please tell me again what that operation will change? When i short rx tx and send a char ?ill get response same char and....?

                                  Comment

                                  • dick_barton
                                    Badcaps Legend
                                    • Aug 2015
                                    • 6642
                                    • Wales

                                    #18
                                    Re: Polaroid P50D300S No picture

                                    I would say that it's stage one to know that what you transmit is what you are receiving so any corruption when connected to the scart socket must be a problem with:-
                                    1. Baud Rate
                                    2. Number of start bits
                                    3. Number of Stop bits
                                    4. Parity
                                    5. Number of data bits 7 or 8 bits

                                    All of which you can be varied in the communication program.

                                    This may be useful
                                    http://electronicshelponline.blogspo...-software.html
                                    Last edited by dick_barton; 08-11-2017, 05:50 PM.
                                    Willing to help but I'm no expert.

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK

                                      #19
                                      Re: Polaroid P50D300S No picture

                                      The baud rate is the unknown, almost every system uses 8N1 Comms (8 bits, no parity, 1 stop, 1 start)
                                      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                      Comment

                                      • tn245
                                        Badcaps Veteran
                                        • Oct 2013
                                        • 530
                                        • UK

                                        #20
                                        Re: Polaroid P50D300S No picture

                                        You ever get anywhere with this? I've got a similar one with the 17mb97 board and no picture. The baud rate is 115200. I see it starting up on rs232 terminal but then it says UART disabled part way through start up and then nothing which is pretty useless as there's no way to see the menus to enable UART.

                                        Comment

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