Announcement

Collapse
No announcement yet.

LG 50" Model 50PCPD No picture or sound, powers up.

Collapse
X
Collapse
 
  • Page of 2
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 template Next
    #1

    LG 50" Model 50PCPD No picture or sound, powers up.

    Current condition: TV powers up and stays on with the green light. The screen is powered on to a dark grey with faint snow effect.

    Buffer board test. Each board was disconnected and the lower half of the screen would lighten up.

    The control board has three LED lights on, D3, D4, D5. I also replaced this board.

    Y-Z sus test. When disconnected and powered up, the screen showed no sign of life. This was done with each one separately. One issue when I connected the Z-sus power cable back up, it sparked a little, this was even after 10 minutes of sitting with no pwer attached.

    Any help would be greatly appreciated. I have fix a few plasma tv's, but this one has me stumped.

    Also when the TV is on, the Z-sus board heat plates stay cool, on the Y-sus the one on the left of the three gets warm.
    Last edited by jrwhites; 09-03-2013, 05:40 PM. Reason: Added info
    Tags: None
    #2
    Re: LG 50" Model 50PCPD No picture or sound, powers up.

    So, are you saying that the lower half of the screen has a picture, or are you saying that it's a faint grey when you remove each of the buffers? Are you sure you don't have sound, or are you possibly just not on an input that would produce sound?

    It sounds to me like you have IPM issues on the Z-Sus and possibly the Y-Sus (under the large heat sinks).

    Is the model 50PC5D, 50PC3D, or some other variation?
    Last edited by capkid; 09-03-2013, 05:51 PM.
    LG Plasma Mal-Discharge Correction Service

    Comment

      #3
      Re: LG 50" Model 50PCPD No picture or sound, powers up.

      If the screen has faint glow but no image, investigate the Y-sus and Z-sus IPMs plus possibly a logic board test if available on these panels.
      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

        #4
        Re: LG 50" Model 50PCPD No picture or sound, powers up.

        The model is a 50PC5D.

        With everything connected is has the dark grey screen with VERY faint snow effect. The R/H top and bottom coreners is looks a little brighter.. If I disconnect either the top or bottom buffer board, the lower half brightens up.

        As for sound, I connected a dvd player. I cannot tell what input channel it is on because I cannot see any image stating so. I tried manually setting the input to change, but nothing happened. I don't even get a crakel from the speakers.

        Thanks for the help so far.

        Comment

          #5
          Re: LG 50" Model 50PCPD No picture or sound, powers up.

          I'd do a quick check of the panel voltages to see how they look:

          PSU: VS, VA
          Y-Sus: Vsc, -Vy
          Z-Sus: Vzb
          Last edited by capkid; 09-03-2013, 06:17 PM.
          LG Plasma Mal-Discharge Correction Service

          Comment

            #6
            Re: LG 50" Model 50PCPD No picture or sound, powers up.

            I guess I better put the control module back in then. Then figure out how to test.

            Comment

              #7
              Re: LG 50" Model 50PCPD No picture or sound, powers up.

              There should be voltage test points on the PSU, Y-Sus, and Z-Sus.
              LG Plasma Mal-Discharge Correction Service

              Comment

                #8
                Re: LG 50" Model 50PCPD No picture or sound, powers up.

                PSU: Measure VS and VA at connector.

                Y-Sus: (1) VSC: Place negative probe on one lead of C14 capacitor (orange cap near bottom of board) and the positive probe on the opposite lead of C14. (2) -Vy: Place positive probe on lead of R85 resistor and negative probe on chassis ground.

                Z-Sus: Place positive probe on Q53's transistor's gate (the tab) and negative probe on chassis ground.
                LG Plasma Mal-Discharge Correction Service

                Comment

                  #9
                  Re: LG 50" Model 50PCPD No picture or sound, powers up.

                  Did the test of the PSU. VA is at 60V exactly what it calls for. The VS is at 194, calls for 190 with a 198 max. All tests done at each connection at the Y-X sus board connections. I'll move onto the Y/X-Sus later on.

                  Comment

                    #10
                    Re: LG 50" Model 50PCPD No picture or sound, powers up.

                    I was able to find the C14 capacitor it was a 250w, it was towards the top middle, I didn't see anything with an orange cap but a few resistor looking things. I checked the two test spots and it was .000, What am I checking there? might be wrong there. The orange capped resistor was named VY, dead as a door nail.

                    As for R85 Y-sus board i had a reading of .000, checked the other side incase i wasn't on the lead in side, it was 58 volts.

                    Couldn't find a Q53 resistor on the Z-sus.

                    Being honest I'm highly mechanically inclined, but learning this electrical thing it new to me. I have fixed two other plasma's without help, but this one is kicking my but! So I appreciate it very much. When I bought this for $40 I figured it was a power supply board or capacitors, they said it died during a storm.

                    Side note, the back panel says model 50PC5D, the inside model number says 50pc504x?
                    Last edited by jrwhites; 09-04-2013, 06:16 PM. Reason: more info

                    Comment

                      #11
                      Re: LG 50" Model 50PCPD No picture or sound, powers up.

                      Did you have your meter on the DC voltage scale and was the TV turned on? Can you post the part numbers of your Y-Sus, Z-Sus, and PSU? I can double-check the test point locations with that info. The terminology you used to describe the parts is all over the board and incorrect, so we'll get you back on track.

                      The fact that it died during a storm most likely points to a bad PSU or main board.
                      Last edited by capkid; 09-04-2013, 06:45 PM.
                      LG Plasma Mal-Discharge Correction Service

                      Comment

                        #12
                        Re: LG 50" Model 50PCPD No picture or sound, powers up.

                        Y-sus board is EBR39522801
                        Z-sus board is EBR39523001
                        PSU - EAY32929001

                        TV was on. The PSU board seemed to check out voltage wise to the sus boards.

                        Comment

                          #13
                          Re: LG 50" Model 50PCPD No picture or sound, powers up.

                          Ok, it's as I suspected: You have a different panel version from the one I'd referenced: 50X4 vs your 50X4P.

                          I found the Y-Sus test points for VSC and -Vy (see attachment), but I can't find any images online that are clear enough to see the VZB, aka Zbias, test point on the Z-Sus. I marked a notation on the board I thought could be pointing to the VZB test point. Please verify what I've marked to make sure they are correct.
                          Attached Files
                          Last edited by capkid; 09-04-2013, 07:12 PM.
                          LG Plasma Mal-Discharge Correction Service

                          Comment

                            #14
                            Re: LG 50" Model 50PCPD No picture or sound, powers up.

                            Thanks I'll check it out tomorrow. As a note to reference, the heat plates. On the Z-sus they never warm up, and on the Y sus only the large one warms up. That could be a clue as well.

                            Thanks again

                            Comment

                              #15
                              Re: LG 50" Model 50PCPD No picture or sound, powers up.

                              Originally posted by jrwhites View Post
                              Thanks I'll check it out tomorrow. As a note to reference, the heat plates. On the Z-sus they never warm up, and on the Y sus only the large one warms up. That could be a clue as well.

                              Thanks again
                              Tom and I both commented on possible Y-Sus and Z-Sus IPM issues in posts 2 and 3. Voltage checks to confirm whether the Y-Sus and Z-Sus outputs are correct will provide more evidence.
                              LG Plasma Mal-Discharge Correction Service

                              Comment

                                #16
                                Re: LG 50" Model 50PCPD No picture or sound, powers up.

                                OK here are the checks.
                                VSC - 109V
                                VY - 5.5V
                                VZ - Irratic, couldn't get much of a reading. One side zero, the other side was bouncing all over in a low voltage range.

                                Comment

                                  #17
                                  Re: LG 50" Model 50PCPD No picture or sound, powers up.

                                  What is the test point for the Vzb? Is it a cap, resistor, or a transistor?

                                  -Vy and VSC voltages seem low. What does the panel label say the spec is for each?
                                  LG Plasma Mal-Discharge Correction Service

                                  Comment

                                    #18
                                    Re: LG 50" Model 50PCPD No picture or sound, powers up.

                                    Did the test of the PSU. VA is at 60V exactly what it calls for. The VS is at 194, calls for 190 with a 198 max. All tests done at each connection at the Y-X sus board connections.

                                    Comment

                                      #19
                                      Re: LG 50" Model 50PCPD No picture or sound, powers up.

                                      The panel label says 5V, VA60V, VS190V

                                      Comment

                                        #20
                                        Re: LG 50" Model 50PCPD No picture or sound, powers up.

                                        Originally posted by jrwhites View Post
                                        The panel label says 5V, VA60V, VS190V
                                        Can you post a pic of the label?

                                        Edit: Can you also post clear pics of the test points on the Y-Sus and Z-Sus?
                                        Last edited by capkid; 09-05-2013, 07:33 PM.
                                        LG Plasma Mal-Discharge Correction Service

                                        Comment

                                        Previous 1 2 template Next
                                        Working...