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Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

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    #61
    Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

    I've managed to disconnect all pins of shorted MOSFET. Added a bit more solder to it and they went away smoothly.
    Diodes still appear shorted although I'm not sure what they should read. Good thing is after disconnecting all 6 shorted mosfets (3 30F131 and 3 RJP30h2a) sc2 shows 150+ kOhms, so it's not shorted anymore. I've soldered cms components long ago, a bit hard but I pulled through, so I'm probably going to buy a repair kit and see how it goes. Anyway, without that the board is fried so...!

    I've also managed to find a spare board from an electronic shop for 90 euros, I've bought it just in case. Best case I end up with a fixed board and a new one!

    Edit: corrected auto cow wreck typos from this stupid iPad...!
    Edit 2: what should daf30a (and these diodes in general) read when I test their resistance ?
    Last edited by CoinCoin88; 11-29-2014, 09:07 AM.

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      #62
      Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

      All these sets damage is usually caused by arcing at the screws that ground the circuitry some of the better rebuild kits give replacement screws and it is recommended that some solder should be carefully added to the ground pads at the screw holes!

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        #63
        Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

        Originally posted by CoinCoin88 View Post
        I've managed to disconnect all pins of shorted MOSFET. Added a bit more solder to it and they went away smoothly.
        Diodes still appear shorted although I'm not sure what they should read. Good thing is after disconnecting all 6 shorted mosfets (3 30F131 and 3 RJP30h2a) sc2 shows 150+ kOhms, so it's not shorted anymore. I've soldered cms components long ago, a bit hard but I pulled through, so I'm probably going to buy a repair kit and see how it goes. Anyway, without that the board is fried so...!

        I've also managed to find a spare board from an electronic shop for 90 euros, I've bought it just in case. Best case I end up with a fixed board and a new one!

        Edit: corrected auto cow wreck typos from this stupid iPad...!
        Edit 2: what should daf30a (and these diodes in general) read when I test their resistance ?
        with those diodes, set meter to diode, test centre to each of the outer legs, if it shows short or continuous beep then I would remove (or lift legs)and check again , check also the pads on the board just in case something else is shorting in cct.

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          #64
          Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

          Originally posted by tvsteve2 View Post
          All these sets damage is usually caused by arcing at the screws that ground the circuitry some of the better rebuild kits give replacement screws and it is recommended that some solder should be carefully added to the ground pads at the screw holes!
          That I know. When I mount a board back in my TV (either a new one or this one hopefully fixed) I plan to add some metallic washers to the screws and loctite to secure them.

          Here are my measurements so far. In red are what I believe is shorted. I'm actually sure 30F131 and RJp30H2A are dead short (that make for 6 igbts).

          As for the diodes, I'm gonna test the way tw2005 just told me and report back!
          (Red: supposedly dead / blue: supposedly OK)

          edit: testing from leg 2 to 1 and 3 for all diodes doesn't show short (same value for both 2-1 and 2-3, I assume this is logical considering the layout of these things).
          Readings (each time, 2-1 and 2-3):
          D401: 333/333
          D421: 260/260
          D432: 389/389
          D641: 333/333
          D643: 333/333
          D642: 333/333

          I'm actually relieved to see that all 4 RFN20 show the same values. So after all it doesn't seem "that bad". Still have to check the buffers and hope ICs were not fried, too.


          edit 2: and thank you very much for you help, it's really nice to find people that knowledgeable who still share and help like this!!
          Attached Files
          Last edited by CoinCoin88; 11-29-2014, 11:01 AM.

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            #65
            Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

            diodes appear to be good, bit confusing with q661 but on 2 legs on one of my 2010 boards, I get that, that would usually fail dead short all pins so ok. On that 178M05 5v reg, I don't know what that should read. Seems off to mine in cct but different board and what pins are you measuring to what?

            Looking like 6 IGBTs and this may work again but I'm wary of FET driver ICs.

            Can you locate q531 an measure resistance. 5 pins, you want across the pins as in my picture
            Attached Files

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              #66
              Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

              Should mention but on Q531 that could be 3Mohms, trust you have a good meter

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                #67
                Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                unfortunately the one i have here stops at 2Mohms... I might get a hand on a better one at my friend's shop though.
                edit: tested with 2M setting, it's stucl at max value. So I don't know if it's 3 Mohms, but it's more than 2, which is a good start

                edit: for the 178m05 I was measuring the same way as igbts. This probably makes no sense anyway so I'll live this one aside for now. I'll grab a repair set off eBay, this seems like an affordable option. best case scenario I end up with a repaired board that works and have a spare "new" one in my closet.
                Last edited by CoinCoin88; 11-29-2014, 11:46 AM.

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                  #68
                  Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                  Originally posted by CoinCoin88 View Post
                  unfortunately the one i have here stops at 2Mohms... I might get a hand on a better one at my friend's shop though.
                  edit: tested with 2M setting, it's stucl at max value. So I don't know if it's 3 Mohms, but it's more than 2, which is a good start
                  If it shows 2meg i 'd say ok,strange meter, i always thought they would go OL or 1 or -1 if out of range.

                  If that's good I would expect the FET driver is good as it is connected to that. check the schematic in that manual. search q16531

                  Comment


                    #69
                    Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                    So that kit in the Uk maybe the go or source the parts yourself

                    Comment


                      #70
                      Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                      Originally posted by CoinCoin88 View Post

                      edit: for the 178m05 I was measuring the same way as igbts. This probably makes no sense anyway so I'll live this one aside for now. I'll grab a repair set off eBay, this seems like an affordable option. best case scenario I end up with a repaired board that works and have a spare "new" one in my closet.
                      does not tell me much, don't know what way you did some of those transistors either. there's 3 combinations I'd try, 1-2,2-3,1-3
                      Last edited by tw2005; 11-29-2014, 11:59 AM.

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                        #71
                        Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                        Originally posted by tw2005 View Post
                        If it shows 2meg i 'd say ok,strange meter, i always thought they would go OL or 1 or -1 if out of range.

                        If that's good I would expect the FET driver is good as it is connected to that. check the schematic in that manual. search q16531
                        By max value I meant it showed 1 when set to 2Mohms. So it's more than 2M at least. I'll measure the way you described later today. I'll buy a lot and get started with it when I receive it.

                        Comment


                          #72
                          Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                          Originally posted by tw2005 View Post
                          does not tell me much, don't know what way you did some of those transistors either. there's 3 combinations I'd try, 1-2,2-3,1-3
                          I've tested everything again from drain to gate and drain to source, as you suggested. Before that I had absolutely no clue of how a MOSFET (ar any transistor, actually) worked. Going through some datasheets help me understand that (and why to test from 2 to 1 and 3). The 6 shorted igbts are short from gate to both source and drain (tested in diode mode, cotinuous beep for 1-2, 2-3, 1-3), so they're really dead short. I'll replace them asap.
                          Q531 seems fine (tested yesterday as you suggested), and IC724 (178M05) seems fine too, with no short between (source|gate) and drain (> 2Mohm), and something like 20kOhm between source and gate.

                          Just to clarify for other diodes (eg. RFNxx, DAF30A...) they show an identical drop value (is that the correct term?) for 2-3 and 2-1, and closed circuit between 1 and 3. Is that normal (judging by the diagram seen here , this seems normal). Am I correct so far ?
                          Last edited by CoinCoin88; 11-30-2014, 08:31 AM.

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                            #73
                            Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                            Originally posted by CoinCoin88 View Post
                            I've tested everything again from drain to gate and drain to source, as you suggested. Before that I had absolutely no clue of how a MOSFET (ar any transistor, actually) worked. Going through some datasheets help me understand that (and why to test from 2 to 1 and 3). The 6 shorted igbts are short from gate to both source and drain (tested in diode mode, cotinuous beep for 1-2, 2-3, 1-3), so they're really dead short. I'll replace them asap.
                            Q531 seems fine (tested yesterday as you suggested), and IC724 (178M05) seems fine too, with no short between (source|gate) and drain (> 2Mohm), and something like 20kOhm between source and gate.

                            Just to clarify for other diodes (eg. RFNxx, DAF30A...) they show an identical drop value (is that the correct term?) for 2-3 and 2-1, and closed circuit between 1 and 3. Is that normal (judging by the diagram seen here , this seems normal). Am I correct so far ?
                            looking good then although it's Vin gnd,Vout for the reg don't know what pins but I'd say ok.

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                              #74
                              Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                              Thanks for clarifying. Anyway, kit purchased from UK seller, will see how it goes when I get it, hopefully by next week.

                              Comment


                                #75
                                Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                Originally posted by Sevenqi View Post
                                Update:
                                Received the parts today, replaced the 6 transistors (3 RJP30H2A, 3 30F131), TV works great now.

                                Steps:
                                1. Replaced the bad 6 transistors with the new one.
                                2. Install the board back to TV, but NOT connect to the buffer boards (SD/SU) (I even disconnected the grounds, no physically touch between the SC and the two buffer boards).
                                3. Shorted the SC50 (I used an old IDE hard drive jumper)
                                4. Plug and Turned on the TV, it powered up constantly, no blinks any more, TV response to the remote control.
                                5. Unplug the power cord from the wall, wait for 5 minutes.
                                6. Connected the SC board with the SU/SD board firmly (connectors and grounds).
                                7. Plug and turned on the power supply, TV lite up ! Everything works !

                                Hello,
                                The same thing happened to me two months ago which made me get a new TV since I have no idea how to fix my broken one. The broken TV is currently sitting in my hallway collecting dust and I dont know what to do to it. It seems like such a waste to throw it away since it is only 2.5 years old.

                                I read your fix and am wondering if the same thing can be done to mine? I saw the part list you mentioned here.

                                Some others are saying to replace Part #TNPA5335 YSUS SC Board Y-Main. But I don't know if that's the problem.

                                Can you help me out?
                                Attached Files

                                Comment


                                  #76
                                  Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                  Hi,

                                  If you go through the last 4 pages, I think you'll get all the information you're looking for.
                                  First step would be to open the TV (~30 screws on the back pannel) and inspect the SC board, located on the left side (rear-facing the TV), along with SU and SD board (left side, along the edges).
                                  Remove the SC board by disconnecting the 3 clips (left) and the ribbon flex cable (right) and unscrew it. You're looking for (tiny) burn marks on the other side of the board, around the screws that attached the board to the TV chassis. Even if you don't see them, there's a good chance you've got (at least) 3 to 6 shorted transistors. Check my post (#64, this page) for a detailed view of my board. Components in red were shorted (although not "blown"), and it seems they're always the one to go.

                                  Read carefully tw2005 advice too as they sum up pretty up everything, including test procedures for these components.

                                  Whatd I'd do:
                                  1) open TV, remove SC board
                                  2) use a multimeter to check for a short at both ends of SC2 connector (board input). If it's shorted (0 ohm), the board is defective and must be either replaced (hard to find) or repaired (ebay, repair kit).
                                  3) if the board is shorted, check all MOSFETs (components labeled Qxxx on the PCB) with your multimeter: pin 1-2, 2-3, 1-3. None should be shorted. If some of them are, carefully unsolder both their pins from the board and lift them so that no contact remain. (add some fresh solder to the legs to help melt the ROhS factory solder, don't hesitate to 'flood' one leg if its solder is reluctant to melt, you'll remove the excess of solder with a braid or a pump).
                                  4) Once you've lifted all legs of shorted MOSFET, check again for a short at SC2. Hopefully, both ends should not be shorted anymore. Replace shorted components with new ones from eBay and add some loctite to the ground screws when replacing the board. I'dd also consider adding some fresh solder to the ground pads of these screws, just to be sure...


                                  edit: If you read carefully you'll find out here that you also have diodes on the board, that look just like the MOSFET but aren't designed in the same way. pin 1 and 3 are in closed circuit from factory state (see diagram I linked to in a previous post for DAF30A). These diodes should be tested between pins 2-1 and 2-3, since 1-3 will always result in a losed circuit whis is normal.
                                  Finally there's the "problem" of small SMD buffers (IC501 I think), which are tricky to diagnose... They're provided in the repair kits, and I guess they should be replaced too, but soldering them will require some skills.
                                  Final tip, to completely remove the shorted MOSFET, first unsolder and lift both legs. Then, melt solder on the little metal plate that's located at their back. At first the solder won't attach, but when you've melted enough (and i mean like 5-10 cm of solder) the solder will find its was under the mosfet, melting the mask that's protecting the pad underneath. Use some pliers to completely lift the MOSFET then.


                                  edit3: as for my TV, I haven't received the repair kit yet (hopefully today?) but i've managed to get my hands on a replacement board taken from a 46" screen. The board number was TNPA5335BH (mine was AG), and the BH rev only lacked a capacitor (250V, 190uF, there were only 3 of them and an empty slot for a 4th one). I took one from my dead board and soldered it to my new one, and the Tv is now working like a charm. I've kept it disassembled for now until I get the parts to repair my original board and test it!
                                  Last edited by CoinCoin88; 12-08-2014, 04:48 AM.

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                                    #77
                                    Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                    Hi guys....I'm new to this forum. I have a TC-P50GT30 that is 2.5 years old that popped and has now 7 blinking lights. From what I am reading the fix for this is pretty rigorous for an electronic newbie like me.

                                    Right now, my TV is in the hallway collecting dust. This there anyplace I can take my TV for repair that anyone knows of that can guarantee their work in the Los Angeles or Orange county area?

                                    Thanks in Advance.
                                    Last edited by TV Newbie; 12-08-2014, 01:28 PM.

                                    Comment


                                      #78
                                      Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                      Well, the fix is not "so" rigorous... I have no clue as to where to find a retailer that will fix it (I live in France), but I've seen some offers on eBay for "repair services".

                                      However if you're steady and have a proper soldering iron + multimeter, you could at least diagnose where the error is coming from. Most likely SC, but you could at the very least check that.

                                      Read my previous post and other interventions here, you'll find plenty of information to get started.

                                      Comment


                                        #79
                                        Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                        hello,

                                        English is not my first language, but I will try to explain you my situation

                                        I have also 7 flashing red light, but since 1 month before I started to have a rather gray bar appear in the lower part of the TV by turning on. It disappear after 5-10 minutes.

                                        My SC card is shorted at this moment when I test it.
                                        When I test the sd/su card does not seem shorted. What to do, I just change the SC board ? What to do to know if I need to change the sd or su board?

                                        My previous symptom tell me that the SD board is bad ?

                                        what is the good resistance value I need have on the su/sd board

                                        is that the SC board can cause a bar in the TV ? or is 100% sure that my SD is bad ?

                                        thanks for your help

                                        Comment


                                          #80
                                          Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

                                          Was the grey bar going from the top to bottom of the screen, or from the left to the right?
                                          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.

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