TNPA4250 Board Repair

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  • canadaboy25
    What is normal?
    • May 2013
    • 509
    • Canada

    #21
    Re: TNPA4250 Board Repair

    Originally posted by tom66
    I would try testing VAD, VSCN and VSET - they can cause 7 blinks error.
    I'm sorry but I have no idea what those are haha

    I'm kinda a noob at plasma's
    canadaboy25

    -Sometimes the light at the end of a tunnel is an on-coming train

    Comment

    • tom66
      EVs Rule
      • Apr 2011
      • 32560
      • UK

      #22
      Re: TNPA4250 Board Repair

      They are voltages marked on the SC board. If in doubt refer to the service manual.
      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

      • canadaboy25
        What is normal?
        • May 2013
        • 509
        • Canada

        #23
        Re: TNPA4250 Board Repair

        Well I connected the power cable to the SC board and left the data plug disconnected so the tv would stay on.

        The VAD tested fine
        The VSCN only had 9.3 volts
        The VSET tested 321 and is supposed to test 365 +or- 7 volts

        I used chassis as ground reference.
        Last edited by canadaboy25; 07-17-2014, 10:11 PM.
        canadaboy25

        -Sometimes the light at the end of a tunnel is an on-coming train

        Comment

        • canadaboy25
          What is normal?
          • May 2013
          • 509
          • Canada

          #24
          Re: TNPA4250 Board Repair

          Any ideas?
          canadaboy25

          -Sometimes the light at the end of a tunnel is an on-coming train

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #25
            Re: TNPA4250 Board Repair

            If VSCN tests bad with the SU/SD unplugged you probably have a short on the SC board, double check you replaced all shorted FETs.
            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

            • canadaboy25
              What is normal?
              • May 2013
              • 509
              • Canada

              #26
              Re: TNPA4250 Board Repair

              I tried disconnecting the SU and SD boards from The SC board and the VSCN voltage is still only 9 volts.

              I tested all of the MOSFET's again and they all tested fine.

              All of the tests were done with the data cable unplugged from the SC board so that the TV would stay on.
              canadaboy25

              -Sometimes the light at the end of a tunnel is an on-coming train

              Comment

              • tom66
                EVs Rule
                • Apr 2011
                • 32560
                • UK

                #27
                Re: TNPA4250 Board Repair

                You may require that cable in to get VSCN, it will be briefly available if there is no fault with it so try that.
                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

                • canadaboy25
                  What is normal?
                  • May 2013
                  • 509
                  • Canada

                  #28
                  Re: TNPA4250 Board Repair

                  With that cable connected the VSCN voltage jumps to 30 volts and climbs to 35 volts but then the TV shuts off.

                  The voltage in the manual is much higher than this or does it just need time to climb up?
                  canadaboy25

                  -Sometimes the light at the end of a tunnel is an on-coming train

                  Comment

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #29
                    Re: TNPA4250 Board Repair

                    It should be around 140V so that is bad.
                    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

                    • canadaboy25
                      What is normal?
                      • May 2013
                      • 509
                      • Canada

                      #30
                      Re: TNPA4250 Board Repair

                      Well of it's not a a shorted transistor what else could it be?
                      canadaboy25

                      -Sometimes the light at the end of a tunnel is an on-coming train

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #31
                        Re: TNPA4250 Board Repair

                        Bad VSCN generator circuit, leaky transistor, bad diode are possibilities.
                        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

                        • canadaboy25
                          What is normal?
                          • May 2013
                          • 509
                          • Canada

                          #32
                          Re: TNPA4250 Board Repair

                          Well I recently picked up an oscilloscope and a desoldering station so those should make troubleshooting go a lot quicker.

                          I have a lot of time to work on this so if you could tell me anything that I should test I would greatly appreciate the help!
                          canadaboy25

                          -Sometimes the light at the end of a tunnel is an on-coming train

                          Comment

                          • tom66
                            EVs Rule
                            • Apr 2011
                            • 32560
                            • UK

                            #33
                            Re: TNPA4250 Board Repair

                            What oscilloscope did you get? That would be very helpful.
                            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

                            • canadaboy25
                              What is normal?
                              • May 2013
                              • 509
                              • Canada

                              #34
                              Re: TNPA4250 Board Repair

                              Originally posted by tom66
                              What oscilloscope did you get? That would be very helpful.
                              I have the Rigol DS2072A.
                              canadaboy25

                              -Sometimes the light at the end of a tunnel is an on-coming train

                              Comment

                              • tom66
                                EVs Rule
                                • Apr 2011
                                • 32560
                                • UK

                                #35
                                Re: TNPA4250 Board Repair

                                Nice choice! Very powerful scope!

                                Connect your oscilloscope to the SC output. If you need help locating where, post a clear picture of it.
                                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

                                • canadaboy25
                                  What is normal?
                                  • May 2013
                                  • 509
                                  • Canada

                                  #36
                                  Re: TNPA4250 Board Repair

                                  Would you like a picture of the SC board?
                                  canadaboy25

                                  -Sometimes the light at the end of a tunnel is an on-coming train

                                  Comment

                                  • tom66
                                    EVs Rule
                                    • Apr 2011
                                    • 32560
                                    • UK

                                    #37
                                    Re: TNPA4250 Board Repair

                                    That would help yes.
                                    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

                                    • canadaboy25
                                      What is normal?
                                      • May 2013
                                      • 509
                                      • Canada

                                      #38
                                      Re: TNPA4250 Board Repair

                                      I apologise in advance for the poor picture quality.

                                      This is such a large board and I don't have a very good camera or lighting.

                                      If you need close-ups of specific areas just let me know.
                                      Attached Files
                                      canadaboy25

                                      -Sometimes the light at the end of a tunnel is an on-coming train

                                      Comment

                                      • tom66
                                        EVs Rule
                                        • Apr 2011
                                        • 32560
                                        • UK

                                        #39
                                        Re: TNPA4250 Board Repair

                                        Can you see a point marked TPSC1?
                                        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

                                        • canadaboy25
                                          What is normal?
                                          • May 2013
                                          • 509
                                          • Canada

                                          #40
                                          Re: TNPA4250 Board Repair

                                          I found that test point.

                                          Am I supposed to scope that output with the TV turned on? If so should i have the main power connector and the data connector coming from the main board connected? If i have the data cable connected then the TV shuts off in a matter of seconds. Will that be long enough to perform a measurement?
                                          canadaboy25

                                          -Sometimes the light at the end of a tunnel is an on-coming train

                                          Comment

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