Announcement

Collapse
No announcement yet.

Lg 60PK550 Problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Lg 60PK550 Problem

    Hello all,

    My first post here. I value your time and expertice greatly, so I'll try to explain myself as thoroughly as possible.

    The TV: LG 60PK550 (plasma)

    The problem: The dang thing wont turn on properly!

    The setup: I've got my system controlled by a logitech universal/multi device remote. For the last week or two, the rest of my system would come on properly, but not the plasma. I chalked it up to not having the remote properly aimed at the tv (it sends a bunch of different IR codes for all of my devices so it can be finicky at times) After manually switching the tv on and off a couple of times it would turn on fine. Once the TV was on, there were no problems.

    Today, no such luck, so I looked at the symptoms more closely. Upon turning on the TV (when operating properly) the power supply makes two sets of clicks once (click-click) when the button is pressed. and again (click-pause-click) when the display fires up.

    So, I press the power button and I get the first set of clicks. the LED indicator light behaves normally, and isn't flashing any error codes, but the second set of clicks never come and the display shows no signs of turning on.

    After unplugging and replugging, I hear 3 clicks of the power supply arming itself and then after pressing power the same thing. One set of clicks and nothing from the display.

    Having recently replaced the caps on an old Macintosh computer PSU with great success, I decided to take the shroud off of the back of the TV and inspect the power supply of the LG for bad caps. Nothing was visible on the top of the board, so I unplugged all the connections, unscrewed the board and looked on the back. No funny business there either.

    It was at this point I figured I'd register on the forum and ask for some advice. In the hour it took for the registration to kick in, I decided to plug the power supply back in and try again to see if I could hear any odd buzzing or clicking from the power board. Here's where it gets funny. After I hooked it all back up and powered it on, it worked normally. So my logical next step was to turn it on and off several times to verify my own sanity. I successfully powered it on and off several times and proceeded to put the shroud back on. After the 5-10 minutes that elapsed as I put the screws back in, I tested it again. Now it's not working again.

    That's the long and the short of it.

    My questions are:

    A) Does this sound like a problem with the main power board not relaying the power to the display? I figure if it is a problem with the caps, it's definitely an intermittent one, perhaps a capacitor is on its way out and is behaving erratically?
    B) Since none of the caps on the psb show visible signs of malfunction, should I just replace them? Might this solve my problem?
    C) Could any of the other boards be the culprit? I did a quick visual check of the other boards, but the main power board is the only one I scrutinized.

    Phew, that was longwinded. Looking forward to your replies.

    #2
    Re: Lg 60PK550 Problem

    When you try to turn the set on, do you see a faint glow from the plasma panel?
    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: Lg 60PK550 Problem

      Holy cow, that was a quick reply.

      No, there is no glow on the display at all.

      When the problem began to occur over the last couple of weeks, I believe there was a faint grayish glow.

      Again, at that point in time I believed the problem to be a product of my remote being weird and not setting the TV to the proper input. So I wasn't paying particular mind.

      But nothing now.

      It should be noted that when the TV is behaving normally, has power, and is in standby mode, the red light is illuminated on the front. Now, after letting the tv sit unplugged for at least 20 minutes, when I plug the cord back in, the standby light doesn't illuminate automatically. It's only after I press the on button that it clicks and goes into standby mode.
      Last edited by fireproof710; 12-10-2013, 06:31 PM. Reason: Incomplete thought....

      Comment


        #4
        Re: Lg 60PK550 Problem

        Sounds like a PSU fault.

        Time to remove the back cover.. take pics of each board and one of entire back of set so we can see the chassis layout.. also one up close of the connector that goes from the PSU (power input) and the main board (one with HDMI, Scart etc) so we can see any writing by the connector.

        Also get a Digital multimeter ready.

        Comment


          #5
          Re: Lg 60PK550 Problem

          I've got the back cover off already. I'll pick up a multimeter after work today and snap some pics.

          Comment


            #6
            Re: Lg 60PK550 Problem

            Here are the pictures. I've got multimeter in hand. Where should I start?
            Attached Files

            Comment


              #7
              Re: Lg 60PK550 Problem

              There's a connector going between the main board (which has the HDMI ports on it) and the power board, can you get a photo of the labels next to 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


                #8
                Re: Lg 60PK550 Problem

                Pics attached. On the main board (w/hdmi jacks etc) there s a label on a ribbon cable with a sticker on it. Below that theres some numbers printed on the board and a barcode and sticker.

                On the power supply board where the cable goes to the main board there are some pin voltages. I snapped a pic of that too if thats helpful.
                Attached Files

                Comment


                  #9
                  Re: Lg 60PK550 Problem

                  I plan on testing the output voltages of the power board this weekend. I found a service manual so that should provide me with any voltages not printed on the power board. I'll post my findings.
                  Last edited by fireproof710; 12-13-2013, 09:16 AM. Reason: brain burp

                  Comment


                    #10
                    Re: Lg 60PK550 Problem

                    Update: I tested all of the output voltages going out of the PSB.

                    The Ysus and Zsus voltages are identical. The pin order is reversed, but the pin labels and values are the same.
                    VS: 202V
                    VS: 202V
                    NC: 0
                    GND: 0
                    GND: 0
                    VA: 60
                    VA: 60
                    GND: 0
                    M5V: 5V
                    M5V: 5V

                    The Logic board voltages are:

                    M5V:5V
                    M5V:5V
                    M5V:5V
                    M5V:5V
                    GND:0
                    GND:0
                    GND:0
                    GND:0

                    The main board pins that have their voltages labeled are all normal (which are all 17V or 5V) The ones that don't have printed values are thus:

                    Pin 18 (M ON) 0V
                    Pin 17 (Auto GND) 4V
                    Pin 16 (RL On) 0
                    Pin 15 (AC Det) 5V
                    Pins 13/14 (Stby) 5V


                    I turned it on and off and theres no image or glow.

                    Does any of this information indicate anything? What else should I test? I haven't checked any of the fuses because they're soldered on to the board. can they be tested without removing them?
                    Last edited by fireproof710; 12-14-2013, 02:21 PM.

                    Comment


                      #11
                      Re: Lg 60PK550 Problem

                      On the top of the back plasma panel metal plate
                      https://www.badcaps.net/forum/attach...6&d=1386802581

                      there should be a label with a model # marked PDP60####### (with # replaced by numbers/letters.) What is this number?
                      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: Lg 60PK550 Problem

                        PDP60R10000

                        Here's a pic. I didn't previously see that the VA and VS voltages are printed on that sticker as well, so those are proper I guess....
                        Attached Files

                        Comment


                          #13
                          Re: Lg 60PK550 Problem

                          Great. 1st file should tell you where the other voltages -Vy, Vsc and Vzbias can be checked:
                          http://tgohome.com/ServiceManuals/?d...&Search=Submit
                          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


                            #14
                            Re: Lg 60PK550 Problem

                            Awesome! I'll get on that asap! Hopefully this evening.

                            Comment


                              #15
                              Re: Lg 60PK550 Problem

                              Update: I re-checked the Va and Vs values on the SMPS (power supply board) Those values are indeed at 60 and 202V respectively, so that's fine.

                              I checked the Vy and VSC values which were 180 and 150 respectively, so thats fine. However in the reference document, it says that the Vy value is -180 and the meter read 180.I made sure to have the +- leads matched up across the resistor. So, not sure if that matters.

                              When I checked the VZB on the Zsus board, the value off of the resistor was 15V instead of 105 as it should be.

                              Comment


                                #16
                                Re: Lg 60PK550 Problem

                                The voltage will read positive, that is OK.
                                Where did you check Vzbias across? That low voltage could cause issues.
                                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


                                  #17
                                  Re: Lg 60PK550 Problem

                                  I checked it across resistor R275 as indicated in the service manual you linked to. ShopJimmy actually has the ZSus board for just over $50:

                                  http://www.shopjimmy.com/lg-ebr63450501-zsus-board.htm

                                  I did a closer visual inspection of the Zsus board for faulty components and can't see anything that looks remotely swollen or deformed. So my next question would be is it worth trying to chase a faulty component on the board or just try swapping the whole board out.

                                  Comment


                                    #18
                                    Re: Lg 60PK550 Problem

                                    What do you think Tom? Are there any particular components that I can check and/or replace on the Zsus board before I order a replacement? The wife is anxious to get the plasma off of the dining room table since I've annexed it as a work space

                                    I suspect that unless there is a well documented fault with the board, it would be more time and resource efficient to just shell out for a whole new board, right?

                                    Comment


                                      #19
                                      Re: Lg 60PK550 Problem

                                      I would concur. Try a new board.
                                      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


                                        #20
                                        Re: Lg 60PK550 Problem

                                        Part ordered! Thanks so much for your help thus far! I'll update once I've swapped the board out. Fingers crossed that that'll take care of it.

                                        Comment

                                        Working...
                                        X