PN42A400C2D issue

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #21
    Re: PN42A400C2D issue

    OK, do you see a point marked Vg or 15V? Does that measure around 15V with the X-main connected?
    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

    • CLANKIRKPATRICK
      Member
      • Sep 2013
      • 26
      • USA

      #22
      Re: PN42A400C2D issue

      My bad...there is sound

      Comment

      • CLANKIRKPATRICK
        Member
        • Sep 2013
        • 26
        • USA

        #23
        Re: PN42A400C2D issue

        i checked the fuse on the y main and it reads 0.9

        Comment

        • capkid
          Badcaps Legend
          • Oct 2010
          • 1339
          • United States

          #24
          Re: PN42A400C2D issue

          Is that 0.9 ohms at the Y-main fuse? Also, there should be VSC (on Y-main) and VE (on X-main) voltage specs on the panel label where VS and VA are displayed. Since you have sound, I'd measure those voltages. There should be a test point on each of the mains for their corresponding voltages.

          Edit: VSC is labeled as "VSCAN" on the Y-main. The test point is near the CN5005 connector.

          The VE test point on the X-main appears to be the R4003 resistor, but I can't see it clearly in a pic I was reviewing. If that is the correct point, you need to place your neg probe on one lead of the resistor and your pos probe on the other lead.
          Last edited by capkid; 09-08-2013, 11:53 AM.
          LG Plasma Mal-Discharge Correction Service

          Comment

          • CLANKIRKPATRICK
            Member
            • Sep 2013
            • 26
            • USA

            #25
            Re: PN42A400C2D issue

            Yeah, .9 ohms on the y fuse....the -vsc is fluctuating between -55 an -80....the ve is steady at 95.4

            Comment

            • tom66
              EVs Rule
              • Apr 2011
              • 32560
              • UK

              #26
              Re: PN42A400C2D issue

              You have a bad Y-main or buffer board then. Isolate the Y-buffer and check -Vy again. If it is still fluctuating, the Y-main is bad.
              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

              • CLANKIRKPATRICK
                Member
                • Sep 2013
                • 26
                • USA

                #27
                Re: PN42A400C2D issue

                I tested the VSCH on the y board, is the v scan the screw?
                Last edited by CLANKIRKPATRICK; 09-08-2013, 11:53 AM.

                Comment

                • CLANKIRKPATRICK
                  Member
                  • Sep 2013
                  • 26
                  • USA

                  #28
                  Re: PN42A400C2D issue

                  how do I isolate the Y- buffer?

                  Comment

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #29
                    Re: PN42A400C2D issue

                    Disconnect it from Y-main, leave it connected to the orange ribbons on panel. Be very careful not to damage/break orange ribbons as these are for the plasma panel module and cannot be replaced if damaged.
                    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

                    • CLANKIRKPATRICK
                      Member
                      • Sep 2013
                      • 26
                      • USA

                      #30
                      Re: PN42A400C2D issue

                      I found the v scan and it fluctuates from -184 to -194 volts

                      Comment

                      • CLANKIRKPATRICK
                        Member
                        • Sep 2013
                        • 26
                        • USA

                        #31
                        Re: PN42A400C2D issue

                        how do I disengage the connections between the buffer and the y main? The white ones..

                        Comment

                        • CLANKIRKPATRICK
                          Member
                          • Sep 2013
                          • 26
                          • USA

                          #32
                          Re: PN42A400C2D issue

                          The both vsch and vscan voltages are stable after removing the buffer, does that mean its a bad buffer board?
                          Last edited by CLANKIRKPATRICK; 09-08-2013, 12:15 PM.

                          Comment

                          • tom66
                            EVs Rule
                            • Apr 2011
                            • 32560
                            • UK

                            #33
                            Re: PN42A400C2D issue

                            Most likely. You can look carefully at the buffer ICs, if you see any burn marks or holes blown in them they are definitely bad.
                            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

                            • CLANKIRKPATRICK
                              Member
                              • Sep 2013
                              • 26
                              • USA

                              #34
                              Re: PN42A400C2D issue

                              So I changed out the Y-buffer today and still have the same problem with the fluctuating voltages on the Y-main. Any thoughts?

                              Comment

                              • capkid
                                Badcaps Legend
                                • Oct 2010
                                • 1339
                                • United States

                                #35
                                Re: PN42A400C2D issue

                                I'd try testing a few components on the Y-main with the board removed from the TV. This Y-main may be a little different from some of the other Samsungs that exhibit failures of the heat sink components when the board is bad. If you find a bad component, I'd replace the Y-main AND the Y-buffer again.
                                Last edited by capkid; 09-11-2013, 07:25 PM.
                                LG Plasma Mal-Discharge Correction Service

                                Comment

                                • CLANKIRKPATRICK
                                  Member
                                  • Sep 2013
                                  • 26
                                  • USA

                                  #36
                                  Re: PN42A400C2D issue

                                  What components exactly? Are you saying I need to buy another buffer in addition to the new one I just bought when I change out the y main?

                                  Comment

                                  • capkid
                                    Badcaps Legend
                                    • Oct 2010
                                    • 1339
                                    • United States

                                    #37
                                    Re: PN42A400C2D issue

                                    I can't tell exactly which components from pics, but there should some transistors and diodes on the heat sinks. I'd personally replace the Y-buffer again if the Y-main proves to be faulty. I haven't found a reliable way to test the buffers, and you risk the Y-buffer killing a replacement Y-main - infinite loop.
                                    Last edited by capkid; 09-11-2013, 08:15 PM.
                                    LG Plasma Mal-Discharge Correction Service

                                    Comment

                                    • CLANKIRKPATRICK
                                      Member
                                      • Sep 2013
                                      • 26
                                      • USA

                                      #38
                                      Re: PN42A400C2D issue

                                      So just hooking up a new y buffer to a faulty y main kills it, and it needs replaced again?

                                      Comment

                                      • tom66
                                        EVs Rule
                                        • Apr 2011
                                        • 32560
                                        • UK

                                        #39
                                        Re: PN42A400C2D issue

                                        In some cases; that being said I've only ever heard of it on older Samsung and LG plasma panels, not on newer ones, I wouldn't entirely rule out the chance.
                                        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

                                        • CLANKIRKPATRICK
                                          Member
                                          • Sep 2013
                                          • 26
                                          • USA

                                          #40
                                          Re: PN42A400C2D issue

                                          That is really frustrating that I killed the brand new buffer just by hooking it up...so should I take the chance on just getting a new Y main or do I need to get yet another y-buffer to go along with it?

                                          Comment

                                          Related Topics

                                          Collapse

                                          • rounin
                                            MacBook Air A2337 (820-02016) USB-C Port Issue – Only Works in One Orientation (CC Line Problem?)
                                            by rounin
                                            Hi everyone,

                                            I'm working on a MacBook Air 2020 (A2337, board 820-02016) and running into a strange USB-C issue. I've gone through quite a bit of testing and part replacement, but I'm stuck — hoping someone here can shed some light.

                                            🛠 Original Issue
                                            The machine initially wouldn't negotiate 20V over USB-C — stuck at 5V.
                                            Diagnosis showed PP1V5_UPC0_LDO_CORE shorted to ground.

                                            I replaced U3100 (UF400) using a donor board (A2179), and the machine powers on fine now.

                                            ⚠️ New Problem: One USB-C Port Only Works in One Orientation...
                                            04-19-2025, 01:18 AM
                                          • ugamazing
                                            Three 820-01700 32GB Logic Boards Same Issue: Won't Wake From Hibernate
                                            by ugamazing
                                            I have three identical-spec 820-01700 boards (2.6/32/512), and ALL THREE boards came to us with the same fault, from different sources: The boards don't wake from hibernation with the keyboard or lid, they ONLY wake when you press the power button. I understand this is a very minor issue, but the boards must be fixed!

                                            We will of course begin with the obvious (checking lid signals), but I couldn't help but notice these three boards were all 32GB variants. Has anyone noticed an issue relating to these 32GB boards in particular? I of course don't think it's a RAM issue, but it's bizarre...
                                            12-17-2024, 07:05 PM
                                          • Simone Vergani
                                            Alienware 15 R2 Service Tag: DL7NN32 ISSUE (Battery is not charging)
                                            by Simone Vergani
                                            Hello everyone,

                                            I'm experiencing an issue with my Alienware 15 R2 (Service Tag: DL7NN32). The laptop works perfectly when connected to the AC adapter — it powers on and functions normally. However, the battery does not charge. If I disconnect the DC adapter, the laptop shuts down immediately, as the battery is at 0%. I have replaced the battery with a new compatible one, but the issue persists. I also replaced the AC adapter with a compatible one, but the battery still doesn't charge.

                                            To assist with troubleshooting, I'm attaching two power circuit schematics:
                                            • Power
                                            ...
                                            03-05-2025, 02:25 PM
                                          • wizard13
                                            Dynabook Satellite Pro C50D-B-100 - BIOS Issue, Black Screen
                                            by wizard13
                                            Hello everyone,

                                            I am experiencing a BIOS-related issue with my Dynabook Satellite Pro C50D-B-100. When I power on the laptop, the screen stays black, and there is no response from the system. I suspect a corrupted BIOS.

                                            I have checked the forum and the available documentation but could not find a solution specific to my issue.
                                            • Brand & Model: Dynabook Satellite Pro C50D-B-100
                                            • Part Number (P/N): PYU13E-00C00PFR
                                            • Serial Number (S/N): 22028896H
                                            • System Configuration (SC): A1PYU13E1127
                                            • Motherboard Model: IP3_ACN16_MB_V21_20211222A
                                            • Power Input: DC 19V –
                                            ...
                                            02-28-2025, 02:43 AM
                                          • Titus6
                                            LG OLE65C1 Stand-By issue
                                            by Titus6
                                            Hello everyone,

                                            I bought an OLED65C1 refurbished TV back in 2022 from a shop. The TV is awesome, this is my first OLED and I really love it.

                                            However I have an issue with the TV since the end of last year. I noticed when my TV is in Stand-By, sometimes the LED goes off then comes back on. When do so it seem periodical. It only goes away for 1-2 seconds, than comes back on. The TV NEVER turnes off, while it's on, so it's not overheating issue or electrical power issue.

                                            I bought a service remote (MKJ39170828) and checked the menu 3. Power On/Off Status. I took...
                                            01-31-2025, 04:01 PM
                                          • Loading...
                                          • No more items.
                                          Working...