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    Hitachi P50H401 - Testing the YSUS board before SDR replacement

    I've been working on a Hitachi P50H401 for a couple of weeks now, learning from this site and other forums as well as I have progressed. I'd really like to get some quality, detailed advice before I plug back in new SDR boards to help ensure that I won't lose them when power is applied.

    Here is my current scenario:

    1) The two 3300uf caps were swollen, so I replaced them both.
    2) The two SDR boards (U and D) were both clearly damaged.
    3) I disconnected both SDR's and connected a video source. It now goes from red to solid blue on the front panel and stays that way. The sound is perfectly fine, but there is (of course) no picture as the SDR's are unconnected to the YSUS board.
    4) I can change channels (as evidenced by the sound of various channels changing) with the DirecTV remote and can change the volume with the Hitachi remote.

    I have checked, double, and triple-checked all of the voltages involved.
    PSU is fine.
    PSU to XSUS is fine (via connector CN23)
    XSUS to YSUS is fine (via connector CN22)
    YSUS from XSUS is fine (via connector CN32)


    My focus is now on the YSUS Board (and, in particular, the two connectors that lead out from the left side to the SDR's):

    THIS is the current crux of the matter. I tested all 25 pins on the lower left connector that comes out of the YSUS board (and ultimately leads into the SDR-D), and ALSO the 25 pins on the YSUS upper left connector (that leads, ultimately, to the SDR-U).

    I assumed that I would find exact voltage matches because both of these connectors are labeled exactly the same on the circuit board itself. That turned out to be the case, the voltages do match, EXCEPT for pin #8 and pin #21 (counting up from the bottom) on the LOWER LEFT CONNECTOR ONLY. Those two read 0.00

    All of the upper left connector pins had readable voltages, including its pin #8 (-24.5v) and pin #21 (-51.8v).


    Note: On both the lower and upper, pin #8 is labeled as DA2 on the circuit board, and pin #21 is labeled as DA1.


    All of this leads to a rather simple question I hope can be answered. Does the fact that I get the two 0.00 readings on the lower left connector mean that this particular YSUS board is entirely defective and must be replaced?

    {Or, can I repair it in some way? Or, as is my hope, these two 0.00 readings will NOT prevent the SDR-D board, or the tv in general, from working properly when I connect it?}

    It seems very odd to me that the upper left YSUS connector has readings at pins #8 and #21 and the lower left YSUS one does not.

    Please feel free to reply in as detailed and as exacting manner as you'd like. I am into this pretty deep, as you can see, and I want to get it right before risking $120+ on the SDR U and D's.

    Thanks in advance for your replies.
    Last edited by kca; 02-19-2016, 11:00 AM.

    #2
    Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

    Hoping that someone with experience with plasma tv's, and Hitachi plasmas in particular, can help with the post above. I am getting the new SDR boards, but am still hesitant to install them without knowing if the YSUS board is functioning properly or not.

    Thanks to anyone who can jump in and help.

    Comment


      #3
      Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

      Follow-up to Post #1 above:

      Help needed. Still trying to determine if my YSUS is defective or not.

      Here are the full voltage readings from taken from both the Upper and Lower connectors (25 pins on each) that come off the left side of the YSUS and head into the SDR's themselves.

      Question is:
      Are these voltages indicative of a properly functioning YSUS board in this Hitachi P50H401 I am working on, or do the two 0.00 readings that are highlighted below proof of a short that will damage one or both SDR's? The only positive values in the list are marked in green.


      PIN ---(UPPER)---NAME---(LOWER)

      25------(52.2)------H1-------(52.2)
      24-----(-51.8)------S1------(-51.8)
      23-----(-51.8)------S1------(-51.8)
      22-----(-51.8)------S1------(-51.8)
      21-----(-51.8)-----DA1------(0.00)
      20-----(-48.8)----OC2-1----(-46.8)
      19-----(-46.8)----FVCC3----(-46.8)
      18-----(-51.8)-----CLK1----(-51.8)
      17-----(-51.8)------S1------(-51.8)
      16-----(-51.8)------S1------(-51.8)
      15-----(-52.2)------S1------(-52.2)
      14------(52.2)------H1-------(52.2)
      13-----(0.00)----No label----(0.00) {these 0.00's are as expected}
      12------(79.0)------H2-------(79.0)
      11-----(-24.5)------S2------(-24.5)
      10-----(-24.5)------S2------(-24.5)
      9------(-24.5)------S2------(-24.5)
      8------(-24.5)-----DA2------(0.00)
      7------(-21.5)----OC2-2----(-21.8)
      6------(-19.5)----FVCC4----(-24.5)
      5------(-23.9)-----CLK2-----(-28.0)
      4------(-24.5)------S2------(-24.5)
      3------(-24.5)------S2------(-24.5)
      2------(-24.5)------S2------(-24.5)
      1-------(79.2)------H2-------(79.2)

      Comment


        #4
        Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

        Hi common issues in these is the ripple off the failed filter caps tends to blow the buffers but nothing else which is odd. Should be fine just to replace both cards and the caps and the Tv should work.
        Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

        https://www.facebook.com/Telford-Tel...7894576335359/

        Comment


          #5
          Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

          Do you mean I should replace caps on the YSUS?

          All of them or certain ones in particular?

          Comment


            #6
            Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

            So, RB123 ....

            those 0.00 readings are not important in any way? That is my primary concern. My plan is to replace the Upper SDR only at first, then fire up the tv (for just a brief period of time) to see if I can get the picture to show up on the top half of the screen.

            Comment


              #7
              Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

              Still seeking more detailed advice on this one. I cannot risk the SDR's again because if I blow one or both due to a bad YSUS (or some other factor), the set will no longer be worth repairing / throwing money toward.

              I would appreciate any and all insight I can get on the information in the posts above. Thank you.

              Comment


                #8
                Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                I see what you are trying to get at.
                Now,I'm no plasma expert,that up front

                Made a few notes on the picture,to me it seems that lower connector is pretty much a mirror image from the upper connector.
                If that statement is true,common sense would then dictate you need to see voltage on pin 8 and 21 on lower connector as seen on upper connector.
                Did you take a resistance reading on pin 8 and 21 to ground,to see if it's shorted?

                I would trace those pins back to the component they are connected too.Is it the same component on both upper and lower?
                If so,does mystery components both read the same or is one(lower) defective?

                Also,RB123 stated ripple from defective caps can blow up the buffers,I would ask him to point out what caps they are and maybe replace those?
                Also,did you measure the new buffers for shorts? Wouldn't be the first time to receive shorted buffer,claiming to be good.
                Attached Files
                Last edited by martino; 03-05-2016, 10:07 PM.
                Proud owner of dozens of broken TV's and many,many,many boards.


                Our website and passion:http://hollenhundshepherds.com/

                Comment


                  #9
                  Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                  I think that's very good advice, martino. I am hesitant, however, to take the YSUS off the chassis for the purpose of tracing it back to the corresponding components, as you've logically suggested, and measuring it from the backside in any way. Hesitant because I have read several sources that said repairing or replacing the YSUS may ultimately interfere with the veracity of the picture.

                  I may have to end up doing what you've suggested, though, if I can't find proof through this forum that the two 0.00 readings are indeed harmless.

                  I can also purchase a relatively inexpensive YSUS and test those 50 pins, but again am hesitant to do this because a replacement of this board can also result in a compromised picture. Also hesitant, of course, of purchasing a YSUS online because it may be defective and end up causing more problems than the one I currently have in there. Does anyone know the degree to which experimenting with the YSUS is likely to cause damage to the picture image?

                  I am still hoping someone out there can either confirm that the 0.00 readings will not prevent the SDR's from operating properly, or tell me how to test the YSUS further without removing/repairing/or replacing it. Perhaps this is impossible, but that's what I would like to know before going any further.

                  Related question:
                  What do DA1 and DA2 mean on a YSUS board? Any insights would be appreciated.

                  Comment


                    #10
                    Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                    Also, martino, I don't think the upper and lower connector pins are mirror images as much as they are corresponding parts. In other words, pin #8 on the upper (counting up from the bottom) is a direct match for pin #8 on the lower (also counting from the bottom of that connector). Both of these pin # 8's are labeled DA2. Pin #21 (still counting from the bottom up) on both connectors is labeled DA1.

                    Same is true for all of the 23 pins involved, I just used #8 and #21 as examples to show the corresponding nature of lower and upper.

                    This image, when zoomed, helps one to see what I mean:

                    http://www.ebay.com/itm/Hitachi-JP54...item3abc7354c0
                    Last edited by kca; 03-06-2016, 12:26 AM.

                    Comment


                      #11
                      Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                      $35 is not bad
                      Proud owner of dozens of broken TV's and many,many,many boards.


                      Our website and passion:http://hollenhundshepherds.com/

                      Comment


                        #12
                        Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                        Yes, it's not so much the cost as it is the risk of a defective replacement board (or, one that is on it's "last legs") .... or the resultant problems that may occur from the simple switching of boards. I would feel much more confident, however, if a new board bought online did have all 25 pin voltages matching up as I originally expected they would. Just trying to keep the expenses down as much as possible on a tv produced in 2006. It's a beautiful set, just not worth much more than the $125 I've already spent on the two buffer boards and the two new power supply caps.

                        It appears that I would have to connect a new board up to the line coming from the XSUS in order to test all of the voltages out in full measure. And hence, the Catch-22. Once connected, the "throwing off" of the picture may then have already occurred. Also, if the new board is defective, it could retroactively injure the power supply (and possibly the XSUS as well?), and I am reluctant to risk that because everything that I have hooked up seems to be in perfect working order as of the current moment except the YSUS itself.

                        Does anyone know how many of the 25 pins I can test out of circuit if I just use my DMM (Digital Multimeter) on a new board that arrives in the mail (i.e., before connecting it to the XSUS line itself)?
                        Last edited by kca; 03-06-2016, 02:00 AM.

                        Comment


                          #13
                          Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                          Does anyone know what will actually happen if I install my new SDR boards (Upper and Lower) WITH A FAULTY YSUS BOARD in place?

                          Meaning, if the SDR's are good and the YSUS is bad, will the tv simply shut down and go into protection mode (where I am likely to see either three or four flashing blue lights)? Will, in essence, the SDR's be protected from damage by the tv's own pre-emptive detection of the bad YSUS?

                          Or, can those IC's on one or both of the SDR boards indeed be damaged by a bad YSUS board as it regards this model of 50" Hitachi plasma (P50H401)?

                          What has me a bit puzzled at the moment is that with the original SDR's currently disconnected from the YSUS, I am getting a solid blue light, with sound operating normally and the ability to change channels with the remote. If the YSUS was indeed faulty, wouldn't the set be going into protective mode and flashing blue lights would appear (even with the SDR's disconnected)? Can I take the solid blue light as proof that the YSUS in functioning properly, or is that reasoning flawed?


                          [I]Note: I have checked all the voltages on both the power supply and the XSUS, and am confident that both of those are in working order.
                          Last edited by kca; 03-07-2016, 08:15 AM.

                          Comment


                            #14
                            Hitachi P50H401 FIXED - (Testing the YSUS board before SDR replacement)

                            Good news! .........


                            ... the Hitachi P50H401 is up and running and has been working perfectly well for the last three hours.

                            Tomorrow, I will post more information/insight as to the final fix and some more pictures as well. Hopefully this arc of this thread will help others down the road who find themselves in the same or a similar situation.

                            Thanks much to those who responded to me earlier and who helped me along the way.


                            ~ kca

                            Comment


                              #15
                              Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                              That's good news
                              Proud owner of dozens of broken TV's and many,many,many boards.


                              Our website and passion:http://hollenhundshepherds.com/

                              Comment


                                #16
                                Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                                Thanks, martino.

                                Well, here is a synopsis of how the Hitachi P50H401 finally got up and running:

                                The DA1 traced back to a processor that was on the upper section of the board (see pic). The DA2, to one that was on the lower section (see pic). I reasoned that they (the processors themselves) were both working correctly due to the fact that I was able to get correct DA1 and DA2 voltages out of the upper YSUS connector that leads in to the upper SDR buffer board.

                                So, I connected the upper SDR buffer board only at first, and got the desired picture across the top half of the screen.

                                Connecting the lower buffer board was a little more risky. But, the risk was mitigated by the fact that I was actually able to find voltages on the pins underneath the top pins on the connector. In other words, I was reminded that there are not really 25 pins on each connector leading out of the left side of the YSUS ..... there are 50 on each connector. The top 25 are obvious, but there are also another 25 that rest underneath the top 25 (see the third pic).

                                When I tested these "underneath pins" on the bottom YSUS connector, they read voltages on DA1 and DA2 that were in line with what I had expected to find all along.

                                So, with that fact in hand, I went ahead and risked connecting the lower SDR board. I figured that it would probably go into protection mode, rather than frying out the IC chips on the lower SDR, based on the notion that I was getting voltage on the underneath pins.

                                It worked, and the full picture came to life. I have been running it off and on for the last couple of days now, and can safely say that the fix was a success.

                                So, if anyone out there is finding 0.00 voltages on the DA1 and/or DA2 pins (at least on the lower connector and on the upper, more obvious, pins of that lower connector), you can safely go ahead and hook up the SDR without reservation. I can't speak for the rest of the pins, but would venture to guess that the same might be true for several of the others.

                                Hope this helps someone out there. These older Hitachi plasmas are quite aesthetically pleasing and have a very good picture considering they are about 10 years old now.

                                If anyone out there needs a little help with their Hitachi plasma set, go ahead and contact me. I will help as much as I can.

                                ~ kca
                                Attached Files
                                Last edited by kca; 03-10-2016, 06:06 PM.

                                Comment


                                  #17
                                  Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                                  Sorry I didnt reply buddy, but glad to hear its working
                                  Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                                  https://www.facebook.com/Telford-Tel...7894576335359/

                                  Comment


                                    #18
                                    Re: Hitachi P50H401 - Testing the YSUS board before SDR replacement

                                    Thanks, RB.

                                    Your advice was spot on.



                                    ~ kca

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