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    Panasonic Vierra 50ST30 Flashing

    Hi all,

    I have read through many repair threads for this model TV however I wanted to start a new thread as to stop confusion between several different types of faults being answered at the same time.

    On to the fault. (7 flashes) Current diagnosis shows dead short on 3 30F131 and 3 RJP30H2A IGBT components located on the SC PCB. Removing the power and the Ribbon cable clears the short at the P board end of the wires. So I have now removed the 6 shorted components (Ended up being 5 1 seemed to survive the killing). I am now in search of replacement parts. Do I have to buy the 30F131 off eBay as that's the only place to get them? Or are there known other replacements that I can purchase from digikey or mouser etc. I would prefer this as we have company accounts with these companies.

    On another note can someone explain the difference between the 30F131 and the RJP30H2A component. datasheet wise they both seem to be fairly equal with the RJP30H2A having a lower amp range/wattage reading. Following this answer is it possible to just buy 6 30F131 components(or replacement type) and put them where the RJP components are situated?

    That is Board 1 diagnostics anyway (SC) on to the next board I found a problem on.

    The SS board also has 3 of the 30F131 components blown at 80ohms instead of a dead short so I will be attempting to fix this in the same method as the SC PCB. On top of this I believe one of the Gate drivers has also blown (corner missing off the component) I know this is a long shot but does anyone know what these components are specifically. They are a 5 pin SOT-23-5 package (Looks like a transistor or an inverter type setup) I would give you the designator but the TV is at home and I am at work. It is located if you follow the Gate pin off 30F131 component it runs through a 7R5 resistor then off to the 5 pin chip I am talking about.

    Has anyone got schematics of the PCBs? or is the training guide the closest documents we have? I am an electronics technician by trade so don't hold back on the technical speak however I specialize in low voltage circuitry and repairs so its slightly different but from what I have seen its just on a larger scale.

    #2
    Re: Panasonic Vierra 50ST30 Flashing

    Schematics may be in 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


      #3
      Re: Panasonic Vierra 50ST30 Flashing

      Thanks Tom, Highly helpful having that document. I have found the bipolar transistor I need from digikey (Had to searched the partnumber in service document then I found TW has a cross reference to similar parts).

      My only unanswered now is whats the difference between the 30F131 and the RJP30H2A component. 1 I believe is N channel and one is PDP but when googling to find the difference between the 2 'types' I cannot find anything. I then found 1 IGBT that was labelled PDP, N Channel so I gave up my search on trying to find the difference.

      I am probably over thinking the difference and there possibly isn't one. So following that outcome Wouldn't a replacement like :
      be suitable for both I know there are difference in current levels etc but the only identical part is on eBay and I would prefer to work with Digikey or Mouser.

      Comment


        #4
        Re: Panasonic Vierra 50ST30 Flashing

        PDP = Plasma Display Panel, i.e. optimised for Plasma TV application. High speed switching with high peak current (100A+), but low average current (only around 2 amps maximum.)
        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


          #5
          Re: Panasonic Vierra 50ST30 Flashing

          Great cheers tom, I see the only difference between the 30F131 and the component I posted above is the watts. The FGD4536 is 220A (30F131 200A) however the FGD is 125W and the 30F131 is 140 - I would say as long as I use sufficient heat cooling this W value shouldn't be an issue. I have found on the SC board that the grounding to the chassis was arcing obviously causing spikes etc so fixing this and the fets+transistor hopefully will fix my TV.

          Can anyone show any reason why I cant use the FGD4536 in place of both the 30F131 and the RJP30H2A component?

          Comment


            #6
            Re: Panasonic Vierra 50ST30 Flashing

            If heatsinking is suitable, there will be no problem using the part with the lower power rating.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment


              #7
              Re: Panasonic Vierra 50ST30 Flashing

              The device wouldn't be dissipating 140W... that's about half the total power the TV could ever use. So power rating shouldn't be a concern.

              You need to also match Qg (gate charge.)
              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


                #8
                Re: Panasonic Vierra 50ST30 Flashing

                Thanks for responses guys, wush i could find a datasheet on the 30F131 so i can match the gate current but no one seems to have that much detail on them. I found a post from tw linking to the overall voltage and watt values but cannot find anything that goes further into detail then that.

                Comment


                  #9
                  Re: Panasonic Vierra 50ST30 Flashing

                  Hi all thought I would throw a quick update on here. I received the FGD4536 components and have put them on the SC board. I then removed a gate driver IC and a 7R5ohm resistor from the SS board so I can continue my tests today (These parts are due to arrive monday or tuesday) - I then removed the SU/SD boards and powered it up. I got 7 blinks so I then applied the SC50 jumper connection and powered it up I now get 6 I currently don't have the SS plugged in (As I removed some components I wont power this up until they arrive) I believe the fact that the jumper mod moved it from 7 flashes to 6 means the SC is now ok? can anyone confirm that for me.

                  Thanks for all your help thus far.

                  Comment


                    #10
                    Re: Panasonic Vierra 50ST30 Flashing

                    6 blinks indicates the fault (if any) is now only in the ERC circuit. Generally this will occur if the plasma panel is not hooked up to SC board or in rare cases SS board. Usually a 6 blink fault won't be harmful to buffer boards.
                    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


                      #11
                      Re: Panasonic Vierra 50ST30 Flashing

                      Thanks tom this is as i thought. I have no ss connected or su/sd as i am awaiting the last few components. Come tuesday i will update again with how it goes.

                      Comment


                        #12
                        Re: Panasonic Vierra 50ST30 Flashing

                        Hi all received the last 2 components today - Powered it up and viola! no more red flashing lights - Now the next problem I am facing is the buttons don't seem to switch it into life. I don't have the remote however is this normal? its now flashing green on power up and then going to solid green and all fans kick in.

                        Comment


                          #13
                          Re: Panasonic Vierra 50ST30 Flashing

                          Hey all another update. I have obtained the remote and when its powered up and full green i can switch it to standby mode and any button makes the power led flash however there is definitely no screen showing up. From what i have read the A board is the culprit. Has anyone done repairs on these. I have done repairs on both the sc and ss boards so i would like to repair the a board too instead of buy another 1. Obviously the main chips are on this pcb and even for a trained electronics techician i know thats a long shot for repair however i would love to hear anyones thought or some things for diagnosis.

                          Cheers, Chris

                          Comment


                            #14
                            Re: Panasonic Vierra 50ST30 Flashing

                            A-board IC9400,01,02 & SC IC16561,62 . I've had a condition similar where the scan data was not getting through due to one of those buffer ic being faulty on the SC near SC20.

                            I'm guessing the A board buffers not knowing the board and the latest PDFs are so low now in res for the schematics that it's virtually impossible for me to make out.

                            Could try AV out into a monitor and see if video is produced. You won't see OSD but if it's on TV and no antenna, no signal should be produced.

                            Comment


                              #15
                              Re: Panasonic Vierra 50ST30 Flashing

                              Cheers TW, I will give the monitor a go. Do you have any diagnostics from your findings or what lead you to find the buffers faulty? (eg voltages in/out etc). I also know I have changed the main IGBT components and its making me wonder whether these are not actually working as they should? however the LED on the SC and SS are lit - Would this indicate to you that those IGBT components are functioning as they should?

                              What did you replace the buffers with? P/N?

                              I also forgot to mention I have not managed to get sound working either if this makes a difference - Updated I have played around with the buffer chips while it was on and all of a sudden I hit the fuzzy noise of no signal. No lights at all on the screen however.

                              I measured the voltages across the 2 buffer chips on the sc board and found that 1 is giving significantly lower voltages than the other ( 1 reading between 1.2V and 5V - The other reading around 0.1v - 1.6v) I am thinking this could be the issue.
                              Last edited by Gatedmk4; 12-10-2013, 03:28 AM. Reason: added sound diagnostics

                              Comment


                                #16
                                Re: Panasonic Vierra 50ST30 Flashing

                                5V line feeds those chips so I'd expect 5v at pins 20 also feeds pin 14 of ic563 and ic565 pin 5.

                                Maybe also disconnect the SC20 ribbon and check that 5v is at pin 1 at A20 on startup although it should trip and go SOS6 with that disconnected just in case it's the A board end.

                                look i can't say for sure this is where the issue is, but I've produced this scenario on one of my TNPA5081 rebuilds which was a mess.

                                My situation was this, originally the P5V resistance was low or virtually shorted, cleared after removing these, one had failed but replaced the lot with brand new from SEARS in the US using a freight forwarder, blew the board up several times more trying to fix it.

                                Ended up with a SC producing SOS7 but nothing was blowing, SU/SD were good. Noticed the SOS7 passed through ic561, I convinced myself I'd fixed everything right so took a punt that a bad IC561 could incorrectly send SOS7 to the A board and that it may have been spiked in the repair process.

                                Scavanged one from a C board, now SOS7 had cleared and everything running, primed screen but no display. This proved the SC was working except not data was getting through for the picture. I replaced again with another recycled part and all done and working.

                                I guess a CRO might help checking signals of which I don't have. If the P5V was bad or low I would expect a SOS trip but i don't know at what point.

                                I have blown those on an A-board due to a dodgy SC20 ribbon and ended with SOS10.

                                As for the part, i never worked it out. i suspect it may be a VHC541 by Toshiba but no markings so a little strange. the package size is unusually smaller than normal and Toshiba was the only brand I could find with the size.

                                If you have any scrap c boards or SS you can find them there to recycle. not much fun hand soldering these either, hot air would be easier i suspect.

                                when you say you played with the buffer chips I hope you don't mean the Su/sd whilst on. i've seen a video of someone who shorted and blew the SC fiddling with the ribbons whilst on.

                                Comment


                                  #17
                                  Re: Panasonic Vierra 50ST30 Flashing

                                  Hi TW,

                                  Sorry I should have been more clear - I was just measuring the voltages along the lines between the resistor divider and the buffer ICs on the SC board and all of a sudden I heard a quiet scratching noise so I turned the volume up and sure enough it was the tuner noise with no input. However I don't know if this is merely coincidence and the TV has been fine for noise the hole time just the amount of AV button pushes had led it to the tuner input thus causing the output of sound. I definitely have no OSD however I will be plugging the monitor into it tonight to see what we can get from that - Thank you for your help so far - It has been most helpful in my quest to get this TV going.

                                  Also 5.15V is on both the Buffer ICs on the SC at pin at 14 - I did not check the others however so I will get some more diagnostics tonight after work and draw out the current voltages/schematic of my board.

                                  Cheers, Chris
                                  Last edited by Gatedmk4; 12-10-2013, 02:40 PM.

                                  Comment


                                    #18
                                    Re: Panasonic Vierra 50ST30 Flashing

                                    Is there anyway for me to test my igbt components? Before adding the fgd4536 components i measured the voltage at aroind 220 volts and after adding them its at 220 still. Im wondering if my gate pin on the fgd4536 components isnt triggering as it has a slightly lowervoltage trigger. If this were true could anyone confirm that the green light on the sc board could come on without it actually being functional and driving the su/sd boards.

                                    Comment


                                      #19
                                      Re: Panasonic Vierra 50ST30 Flashing

                                      Another quick update. I have metered out the gate pins on the fgd4536 components and they are flicking between 2.5v and gnd which leads me to believe they are triggering also the 220v side is pulsing down as they trigger. However heres the strange part. Every other 30f131 component has over 100v on their gate pin. This is also on the ss circuit they appear to ave 600v pulsing up and down which seems wrong to me as the max voltage on the components is 360. Any ideas anyone? The high voltage is only on the ss board emitter side of the 30f131 components.

                                      I have no removed my FGD4536 components and moved the 30F131 components from the SU/SD side of the so basically the Watts capacity wasnt there however it would give me an indication if my components were the ones causing the issues. No go unfortunately (or fortunately depending on which way you look at it) I am now reinstalling the FGD components so everything is getting plenty of power.

                                      I had a quick search of the 74VHC541 you mentioned TW and it looks very similar Pin to Pin - I also find interesting the output voltages are basically driven to VCC providing I am reading that right - VCC 5V would give you an output voltage from each buffer line of VCC +/- 0.5. This is giving me some confidence that the Line driver could be faulty as 1 chip I have up to 5v on output lines however the other I only have 0.5-1.5v range.

                                      Of course this is just a component you have found to be similar so the characteristics could be completely different however in general driver components the output voltage is always close to what you feed it via VCC anyway.

                                      Still hunting!
                                      Last edited by Gatedmk4; 12-11-2013, 04:20 AM.

                                      Comment


                                        #20
                                        Re: Panasonic Vierra 50ST30 Flashing

                                        I have also found its only 1.6k from pin 1 of a20 to gnd. However that voltage is stable just for your info. Seems a little low on the resistance but when powered up its 5.15v solid

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