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Toshiba 40RV525R service manual?

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    Toshiba 40RV525R service manual?

    Anybody worked on this model TV before?
    I can't find anything on the net about it. Any help would be appreciated.
    No video, no audio(can't verify since it's no video and can't adjust anything on it).
    It only has a green led constantly on when powered on.
    No 12v and no 24V. The only voltage that it's OK is the 5V. I can't see any 3,3 V markings at the connectors.

    #2
    Re: Toshiba 40RV525R service manual?

    Check the PS_ON signal from the main board back to the power supply.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment


      #3
      Re: Toshiba 40RV525R service manual?

      The TV is at my work place(one of my colleagues bought it for $65 to fix it), so I will try it on Monday. Thank you for your help.

      Comment


        #4
        Re: Toshiba 40RV525R service manual?

        Hi,

        Thanks for the tip! We measured the PS_ON signal from the main board and it gave a solid 3.6V. Also, there is a 5V stand by voltage to the main board.

        The PS does not output anything on the 12V pins to the inverter. Nor is there any voltage on the 12V or 24V pins going to the main board.

        Is there anything else I can check before I can exclude the main board and inverter and starting probing and replacing parts on the PS board?

        Btw, these are the pinouts that go to main board:

        1,2 Gnd
        3,4 24v+
        5,6,7 Gnd
        8,9 12v+
        10,11,12 5v+
        13 Pwr
        14 ACD
        15 D1m
        16 Inv

        Pinouts to inverter board:

        1,2,3,4,5 +24v
        6,7,8,9,10 GND
        11 N. C
        12 INV
        13 D1 M
        14 N. C

        I am not sure what the ACD, D1m and INV stand for. Should I check these?

        Comment


          #5
          Re: Toshiba 40RV525R service manual?

          Originally posted by Bmellero View Post
          Hi,

          Thanks for the tip! We measured the PS_ON signal from the main board and it gave a solid 3.6V. Also, there is a 5V stand by voltage to the main board.

          The PS does not output anything on the 12V pins to the inverter. Nor is there any voltage on the 12V or 24V pins going to the main board.

          Is there anything else I can check before I can exclude the main board and inverter and starting probing and replacing parts on the PS board?

          Btw, these are the pinouts that go to main board:

          1,2 Gnd
          3,4 24v+
          5,6,7 Gnd
          8,9 12v+
          10,11,12 5v+
          13 Pwr
          14 ACD
          15 D1m
          16 Inv

          Pinouts to inverter board:

          1,2,3,4,5 +24v
          6,7,8,9,10 GND
          11 N. C
          12 INV
          13 D1 M
          14 N. C

          I am not sure what the ACD, D1m and INV stand for. Should I check these?
          It's REALLY hard to troubleshoot without any more than a general idea of what I am dealing with. Pictures help us help you. Note my signature in the previous post.

          You have mostly verified the problem is not the main board; Pwr is USUALLY active high, but there are cases where the reverse is true. You might check to see if it changes when you hit the power button. If it doesn't, we'll deal with that later. Also, try this with the inverter disconnected. We had one memorable case on a monitor where a great deal of time and money was spent trying to troubleshoot a power supply problem when the actual fault was a shorted transistor in the inverter.

          The next thing to check would be the voltage across the large cap when the Pwr is high, and when it is low. I would expect it to be about 380 volts when Pwr is active, 1.4 x your AC line voltage when Pwr is inactive. If there is any ambiguity, disconnect the leads from the power supply to the main board and to the inverter. Next, use a resistor in the 2K - 3K ohm range (exact value is not critical) between Pwr and 5V+. Check the voltage across the large cap and the 12V+ and 24V+ pins. Next connect the resistor between Pwr and Gnd and recheck the voltage across the large cap and the 12V+ and 24V+ pins.

          Information and interpretation of results: Most power supplies used in TVs are of a similar design. There is a standby supply which is always on whenever the TV is receiving AC power, and a main supply which is controlled by the main board. In addition there is a PFC front end that when active will boost the voltage across the large cap from 1.4 x line voltage up to 375 - 400 volts. The PFC may be controlled by the Pwr signal or by a current sense circuit. The tests may show if the Pwr signal is active low or high. Note the Power LED is not a good indication - some designs turn the Power LED off when the TV is turned on. If the results show the main supply is not turning on, the first place to look is the SMPS controller for the main supply. By comparing the voltages on the IC to those in the datasheet you may be able to determine the nature of the problem.

          Answers. Dim (not D1m) controls the brightness of the backlights. Inv turns the inverter on. ACD may be AC Detect, and is important. No signs of a service manual from the usual sources.

          PlainBill
          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

          Comment


            #6
            Re: Toshiba 40RV525R service manual?

            Hi pictures would be good- there is currently a lengthy thread on the go for a 40RV525U I can find the difference on specs other than the weight & vesa holes if they use the same boards we would then have two to compare/contrast.
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment


              #7
              Re: Toshiba 40RV525R service manual?

              Thanks. I will upload some pictures of the boards and report the test results in my next post. PFC stands for power factor correction, right?

              Comment


                #8
                Re: Toshiba 40RV525R service manual?

                Originally posted by Bmellero View Post
                PFC stands for power factor correction, right?
                Yes. Please upload your pictures following my sig file below exactly.
                --- begin sig file ---

                If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                Please do not post inline and offsite as they slow down the loading of pages.

                --- end sig file ---

                Comment


                  #9
                  Re: Toshiba 40RV525R service manual?

                  I measured the line voltage across both of the large caps on the power board and get 166Vdc over each one. Switching the Pwr signal via the power button has no effect on boosting the line voltage up to 375-440V even though the Pwr signal high is 3.6V and low is 50mV when I do this.

                  As PlainBill suggested, I will disconnect the mainboard and do the same test with the 2k-3k resistor between Pwr and 5v and then between Pwr and Gnd. I am not to sure what the purpose of this test is. Could someone please explain?

                  I have included photos in this post, mainly of the power board. Please let me know if I should add more.

                  Thanks,

                  Bmellero
                  Attached Files

                  Comment


                    #10
                    Re: Toshiba 40RV525R service manual?

                    Originally posted by Bmellero View Post
                    I measured the line voltage across both of the large caps on the power board and get 166Vdc over each one. Switching the Pwr signal via the power button has no effect on boosting the line voltage up to 375-440V even though the Pwr signal high is 3.6V and low is 50mV when I do this.

                    As PlainBill suggested, I will disconnect the mainboard and do the same test with the 2k-3k resistor between Pwr and 5v and then between Pwr and Gnd. I am not to sure what the purpose of this test is. Could someone please explain?

                    I have included photos in this post, mainly of the power board. Please let me know if I should add more.

                    Thanks,

                    Bmellero
                    There are several reasons for the 'No main supply output' fault. One is an excessive load on either the main board or the inverter. By disconnecting those loads and turning the main supply via the resistor we can determine if the failure is on the power supply or an external board.

                    IF the failure is on the power supply it is helpful to know if the fault is on the 'hot' or 'cold' side of the board. If the PFC kicks in and boosts the voltage across the caps we can be sure the 'on' signal is being coupled across the boundary. Unfortunately, this power supply does not have a PFC front end, so that clue isn't available.

                    We will need a single high resolution (close to, but not over 2000 pixels on a side) picture of the bottom of the power supply if the resistor test does not turn on the main supply.

                    PlainBill
                    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                    Comment


                      #11
                      Re: Toshiba 40RV525R service manual?

                      If it helps, I believe this power supply uses the two caps as a voltage doubler to generate around 325V in for a 115V AC input (162Vpk). ComputerGeek has a similar problem with a similar supply.
                      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


                        #12
                        Re: Toshiba 40RV525R service manual?

                        With the inverter and main board disconnected I placed a 2k resistor between (PWR and Gnd as well as PWR and 5V) and measured the voltage over both the caps. There was no change, still 166 Vdc over the caps. There was also no 12 or 24V either. So I guess the fault is on the main supply somewhere, right?

                        Comment


                          #13
                          Re: Toshiba 40RV525R service manual?

                          I can tell from the picture that this power supply does not have PFC Voltage booster circuits, there is a small transformer on the top left for the standby PS, the large transformer on the bottom will more likely be for the 12v/24v power supply. and two common mode chokes for input line filter Since you supply the PC_ON and it still does not turn on the 12v/24v section, then we will need good clear pictures of the bottom side of the board, take a lot of closed up in MACRO mode will be good. i would wok on the board by itself and you can use lamps for load.
                          Never stop learning
                          Basic LCD TV and Monitor troubleshooting guides.
                          http://www.badcaps.net/forum/showthr...956#post305956

                          Voltage Regulator (LDO) testing:
                          http://www.badcaps.net/forum/showthr...999#post300999

                          Inverter testing using old CFL:
                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                          http://s807.photobucket.com/user/budm/library/

                          TV Factory reset codes listing:
                          http://www.badcaps.net/forum/showthread.php?t=24809

                          Comment


                            #14
                            Re: Toshiba 40RV525R service manual?

                            How do we know if the 12/24v section it's on or not? There is no voltage at the connector, but maybe it's on.
                            Somebody could explain to us in general how these power supplies work, how the voltages are going through the power supply?
                            There is one voltage going through the transformer and then gets separated into 5, 12 and 24v? Which main components are responsible for each of these voltages?
                            How we can be sure that the primary circuit it's good? Or better yet, how we can isolate the problematic circuitry?
                            This is the reason I gave up on my Vizio power supply, because I don't understand how these power supplies work.

                            We are colleagues at work and we are trying to fix this TV together. I dragged him into this

                            Comment


                              #15
                              Re: Toshiba 40RV525R service manual?

                              Originally posted by tibimakai View Post
                              Somebody could explain to us in general how these power supplies work, how the voltages are going through the power supply?
                              Budm's guide

                              https://www.badcaps.net/forum/showpo...4&postcount=32
                              --- begin sig file ---

                              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                              Please do not post inline and offsite as they slow down the loading of pages.

                              --- end sig file ---

                              Comment


                                #16
                                Re: Toshiba 40RV525R service manual?

                                Let me try making a basic block diagram to explain basic principle on how most power supplies in the LCD TV works. I will post it when I finished.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #17
                                  Re: Toshiba 40RV525R service manual?

                                  that would be great!!! thank you very much for your effort.

                                  Comment


                                    #18
                                    Re: Toshiba 40RV525R service manual?

                                    Just for the heck of it do you have this component in this post?
                                    https://www.badcaps.net/forum/showpo...&postcount=120


                                    If you do set your meter to 200ohms and measure pins 10 and 12 (Take notice of the Dot on the Component it indicates pin 1) highlighted in black and red, post the result back here.

                                    Budm I am waiting for that diagram too, can't wait to see it.

                                    Comment


                                      #19
                                      Re: Toshiba 40RV525R service manual?

                                      Here is the most simple and basic diagram that I come up with that is not too complicate, I hope not.
                                      Attached Files
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment


                                        #20
                                        Re: Toshiba 40RV525R service manual?

                                        Budm Thanks for that diagram! I was expecting to see something a little more focused on a SMPS, do you know where I could find something like that? I know every SMPS is different but is there like a common diagram on how the power is stepped up, converted, how the actual Switching part works. And if the power supply has a PFC section how that works, do you know if there is anything like that?

                                        tibimakai Sorry to Hijack your thread.

                                        Comment

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