Curtis lcd3215a Standby power only

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • retiredcaps
    Badcaps Legend
    • Apr 2010
    • 9271

    #21
    Re: Curtis lcd3215a Standby power only

    You have at least 3 voltage regulators on your main board, possibly more, but the main board picture is obscured by wiring and the angle shot.

    See my sig file on how to test a voltage regulator.

    Note to selldoor. There are no regulators on the back although I do see a few diodes.
    Attached Files
    Last edited by retiredcaps; 08-28-2012, 11:35 PM.
    --- begin sig file ---

    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

    We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

    Please do not post inline and offsite as they slow down the loading of pages.

    --- end sig file ---

    Comment

    • allsmith
      Senior Member
      • Aug 2012
      • 179
      • United States

      #22
      Re: Curtis lcd3215a Standby power only

      Originally posted by retiredcaps
      You have at least 3 voltage regulators on your main board, possibly more, but the main board picture is obscured by wiring and the angle shot.

      See my sig file on how to test a voltage regulator.

      Note to selldoor. There are no regulators on the back although I do see a few diodes.
      Thanks !! I tested 5, U designation regulators on main board,here are the results..

      u18
      78d051
      ebvhab
      pin 1 = 0.39v
      pin 2 = 0.00v

      u11
      vc33c
      r133al
      pin 1 = 0.00v
      pin 2 = 5.11v
      pin 3 = 3.30v

      u15
      eh13a
      828n90
      pin 1 = 0.00v
      pin 2 = 0.00v
      pin 3 = 0.45v

      u2
      eh11a
      839k32
      pin 1 = 0.00v
      pin 2 = 0.00v
      pin 3 = 0.45v

      u4
      eh13a
      828n90
      pin 1 = 0.00v
      pin 2 = 0.00v
      pin 3 = 0.00v
      Attached Files

      Comment

      • allsmith
        Senior Member
        • Aug 2012
        • 179
        • United States

        #23
        Re: Curtis lcd3215a Standby power only

        Quote from retiredcaps''The main board uses the PS_ON pin to tell the rest of the power supply to start. If PS_ON is low, then the power supply will not start.'' end quote

        I might be misunderstanding you,but the blue wire that is PS_ON, only has voltge (5v) on it when power button is turned on.
        No voltage when power button is off.

        The purple wire has 5v on it at all times.(would that mean that is the standby power for the main board?)

        So if the main board is sending 5v through PS_ON to the power supply,wouldnt the 5v its getting be HIGH(on) and 0v be low (off)??

        Or is it suppossed to be higher than 5v to trigger power supply??

        Sorry if i'm misunderstanding you.

        Also how do i Quote just part of somebodys post and get it to show up in blue like you are doing?? I cant figure it out!! Man! not only am i a noob at electronics and photography! im also a noob at forums!! lol sorry
        Last edited by allsmith; 08-29-2012, 04:10 AM.

        Comment

        • tom66
          EVs Rule
          • Apr 2011
          • 32560
          • UK

          #24
          Re: Curtis lcd3215a Standby power only

          I think the main board is fine. Since PSON is rising, the PSU is the fault.

          There are a few possibilities, the most likely is a shorted diode or startup cap.

          Let's try diodes first -

          All tests done with power supply unplugged and removed from TV.

          Red circled diode: Test from the indicated arrow direction (positive) to the bar (negative) - you should get around 300 to 800. Then reverse the leads, it should read "1".

          Blue circled diodes: Check each other pin to the center pin, in all directions. For example, if you numbered the pins from 1 to 3 starting from the top, you should test: 1->2, 2<-1, 3->2, 2<-3. And you should get readings of around 100 to 600 for each of the "->", but "1" for each "<-".

          Orange circled device - please check what the designator is. Is it "Dxxx" or "Qxxx"? (where xxx is a 3 digit number)
          Attached Files
          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

          • selldoor
            Slow Learner
            • Dec 2010
            • 7870

            #25
            Re: Curtis lcd3215a Standby power only

            Originally posted by allsmith
            Also how do i Quote just part of somebodys post and get it to show up in blue like you are doing?? I cant figure it out!! Man! not only am i a noob at electronics and photography! im also a noob at forums!! lol sorry
            I can help with the easy bits

            I dont know how others do it I have a labour intensive method
            To reply click on Blue "quote" right hand side
            Highlight and press delete to get rid of bits you dont want
            To answer multiple bits with answers between I Highlight and cut the
            Sq Bracket/QUOTE Sq Bracket and place it at the end of each part I want to quote and do the same for the SqBracket QUOTE Sq Bracket (delete =allsmith;261886 ) and place it at the beginning. You could of course just type Sq Bracket etc where you wanted it.

            Just to check you have it right instead of posting go to preview post.
            It is a lot simpler to do than to explain how to do it!!!
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment

            • allsmith
              Senior Member
              • Aug 2012
              • 179
              • United States

              #26
              Re: Curtis lcd3215a Standby power only

              Originally posted by tom66
              I think the main board is fine. Since PSON is rising, the PSU is the fault.

              There are a few possibilities, the most likely is a shorted diode or startup cap.

              Let's try diodes first -

              All tests done with power supply unplugged and removed from TV.

              Red circled diode: Test from the indicated arrow direction (positive) to the bar (negative) - you should get around 300 to 800. Then reverse the leads, it should read "1".

              Blue circled diodes: Check each other pin to the center pin, in all directions. For example, if you numbered the pins from 1 to 3 starting from the top, you should test: 1->2, 2<-1, 3->2, 2<-3. And you should get readings of around 100 to 600 for each of the "->", but "1" for each "<-".

              Orange circled device - please check what the designator is. Is it "Dxxx" or "Qxxx"? (where xxx is a 3 digit number)
              Diode circled in red...DMM on diode test
              Positive to bar=540
              reverse=1/OL

              Devise in orange is designated as Q10(I believe is a mosfet,too close to heat sink to read part#)Test done with DMM set to diode test=

              Q10
              1-2=540
              2-1=1/OL IS Q10 reading failed open here?
              2-3=1/OL
              3-2=1/OL

              Devises in blue are from top to bottom of pic

              D10
              B304G
              switchmode rectifier

              D15
              sf1603g
              rectifier

              D6
              stp520150ct
              high voltage
              schottky
              rectifier

              These D designation devises are the ones im having trouble testing
              originaly i tested them on 200 ohm setting and find all of them to read shorted

              how would i test these rectifiers??
              With diode test or ohm test
              Diode test is erratic and will even cause the Dmm to beep continuity

              Comment

              • allsmith
                Senior Member
                • Aug 2012
                • 179
                • United States

                #27
                Re: Curtis lcd3215a Standby power only

                Originally posted by selldoor
                I can help with the easy bits

                I dont know how others do it I have a labour intensive method
                To reply click on Blue "quote" right hand side
                Highlight and press delete to get rid of bits you dont want
                To answer multiple bits with answers between I Highlight and cut the
                Sq Bracket/QUOTE Sq Bracket and place it at the end of each part I want to quote and do the same for the SqBracket QUOTE Sq Bracket (delete =allsmith;261886 ) and place it at the beginning. You could of course just type Sq Bracket etc where you wanted it.

                Just to check you have it right instead of posting go to preview post.
                It is a lot simpler to do than to explain how to do it!!!
                thanks! i'll keep trying,I tried it once like you do it and think i deleted one of sq Brackets and then it didnt show up in blue.

                Comment

                • Th3_uN1Qu3
                  Believe in
                  • Jul 2010
                  • 6031
                  • Romania

                  #28
                  Re: Curtis lcd3215a Standby power only

                  Q10 may, or may not be open. Without giving a part ID i can't tell for sure.

                  As for the diodes, try unsoldering one and and testing them that way on the diode test.
                  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

                  • allsmith
                    Senior Member
                    • Aug 2012
                    • 179
                    • United States

                    #29
                    Re: Curtis lcd3215a Standby power only

                    Originally posted by Th3_uN1Qu3
                    Q10 may, or may not be open. Without giving a part ID i can't tell for sure.

                    As for the diodes, try unsoldering one and and testing them that way on the diode test.
                    Q10
                    P40NF03LA
                    n channel mosfet

                    test in circuit Dmm set to diode
                    1-2=OL
                    2-1=OL
                    2-3=OL
                    3-2=540
                    1-3=OL
                    3-1=OL

                    Q8
                    P40NF03LA

                    1-2=OL
                    2-1=OL
                    2-3=OL
                    3-2=546
                    1-3=OL
                    3-1=OL

                    Q8 & Q10 in red box in pic
                    Attached Files

                    Comment

                    • tom66
                      EVs Rule
                      • Apr 2011
                      • 32560
                      • UK

                      #30
                      Re: Curtis lcd3215a Standby power only

                      OK so this means pin 3 is source, pin 2 is drain and pin 1 is gate (by deduction). The FETs look good. I am trying to work out a way to test controller Vcc. It may involve soldering a wire to a pin and testing that instead (as the Vcc pin is on the bottom), if you are OK to do that?
                      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

                      • Th3_uN1Qu3
                        Believe in
                        • Jul 2010
                        • 6031
                        • Romania

                        #31
                        Re: Curtis lcd3215a Standby power only

                        Btw, for the diodes, i meant "try unsoldering one end". Sorry, i was in a hurry.
                        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

                        • allsmith
                          Senior Member
                          • Aug 2012
                          • 179
                          • United States

                          #32
                          Re: Curtis lcd3215a Standby power only

                          Originally posted by tom66
                          OK so this means pin 3 is source, pin 2 is drain and pin 1 is gate (by deduction). The FETs look good. I am trying to work out a way to test controller Vcc. It may involve soldering a wire to a pin and testing that instead (as the Vcc pin is on the bottom), if you are OK to do that?
                          Sure i can try anything you want me too,i appreciate the help!!

                          Now are we talking about the 4 rectifiers on the one heat sink,that are giving me trouble testing? Or are we good there and your onto something else?

                          Explain to me what the contoller Vcc is please
                          Not exactly sure what that is

                          Thank you!

                          Comment

                          • tom66
                            EVs Rule
                            • Apr 2011
                            • 32560
                            • UK

                            #33
                            Re: Curtis lcd3215a Standby power only

                            Originally posted by allsmith
                            Sure i can try anything you want me too,i appreciate the help!!

                            Now are we talking about the 4 rectifiers on the one heat sink,that are giving me trouble testing? Or are we good there and your onto something else?

                            Explain to me what the contoller Vcc is please
                            Not exactly sure what that is

                            Thank you!
                            I'm talking about the little black chips on the bottom of the board. Each of these has a voltage supply called Vcc. A failed Vcc supply could explain the problem and it's a fairly common problem with power supplies. It looks like the only way to probe is from the bottom.

                            Since the standby is good (you have a standby LED and PSON goes high to 5V), the problem is almost certainly with the main power supply, which generates the 24V, and likely other rails like 12V, too.

                            Can you get the part # of the device I've circled in the image?
                            Attached Files
                            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

                            • allsmith
                              Senior Member
                              • Aug 2012
                              • 179
                              • United States

                              #34
                              Re: Curtis lcd3215a Standby power only

                              Originally posted by tom66
                              i'm talking about the little black chips on the bottom of the board. Each of these has a voltage supply called vcc. A failed vcc supply could explain the problem and it's a fairly common problem with power supplies. It looks like the only way to probe is from the bottom.

                              Since the standby is good (you have a standby led and pson goes high to 5v), the problem is almost certainly with the main power supply, which generates the 24v, and likely other rails like 12v, too.

                              Can you get the part # of the device i've circled in the image?
                              ic2
                              3843b
                              stez749

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #35
                                Re: Curtis lcd3215a Standby power only

                                Attached Files
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment

                                • tom66
                                  EVs Rule
                                  • Apr 2011
                                  • 32560
                                  • UK

                                  #36
                                  Re: Curtis lcd3215a Standby power only

                                  OK pin 7 is Vcc.

                                  Next to pin 1 there should be a small dot (sunk in the epoxy package)... could you mark this dot on an image as I'm having difficulty making it out on the image.
                                  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

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #37
                                    Re: Curtis lcd3215a Standby power only

                                    Not sure if you have already changed/checked these components or not.
                                    Attached Files
                                    Never stop learning
                                    Basic LCD TV and Monitor troubleshooting guides.
                                    http://www.badcaps.net/forum/showthr...956#post305956

                                    Voltage Regulator (LDO) testing:
                                    http://www.badcaps.net/forum/showthr...999#post300999

                                    Inverter testing using old CFL:
                                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                    http://s807.photobucket.com/user/budm/library/

                                    TV Factory reset codes listing:
                                    http://www.badcaps.net/forum/showthread.php?t=24809

                                    Comment

                                    • budm
                                      Badcaps Legend
                                      • Feb 2010
                                      • 40746
                                      • USA

                                      #38
                                      Re: Curtis lcd3215a Standby power only

                                      error: double posted
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment

                                      • allsmith
                                        Senior Member
                                        • Aug 2012
                                        • 179
                                        • United States

                                        #39
                                        Re: Curtis lcd3215a Standby power only

                                        Originally posted by tom66
                                        OK pin 7 is Vcc.

                                        Next to pin 1 there should be a small dot (sunk in the epoxy package)... could you mark this dot on an image as I'm having difficulty making it out on the image.
                                        Sorry Tom,there is no indent circle on KA3843B,Even tried 20x magnification.
                                        I hope it wasnt painted on and it rubbed off when i quickly cleaned the devise with a q-tip and rubbing alcohol! The other IC's on the board have the indent,Have you ever seen them painted on??
                                        Attached Files

                                        Comment

                                        • budm
                                          Badcaps Legend
                                          • Feb 2010
                                          • 40746
                                          • USA

                                          #40
                                          Re: Curtis lcd3215a Standby power only

                                          "1" is printed right on the board, at the bottom left pin where the IC is. Number 8 is printed right on the board by the top left pin of the IC.
                                          Never stop learning
                                          Basic LCD TV and Monitor troubleshooting guides.
                                          http://www.badcaps.net/forum/showthr...956#post305956

                                          Voltage Regulator (LDO) testing:
                                          http://www.badcaps.net/forum/showthr...999#post300999

                                          Inverter testing using old CFL:
                                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                          http://s807.photobucket.com/user/budm/library/

                                          TV Factory reset codes listing:
                                          http://www.badcaps.net/forum/showthread.php?t=24809

                                          Comment

                                          Related Topics

                                          Collapse

                                          • tvguy12012012120
                                            Zombie Samsung UN55NU6900F dead / no standby voltage - randomly came to life after hours of troubleshooting then died
                                            by tvguy12012012120
                                            This is my first attempt at troubleshooting a board like this, I know I could just buy a new board but I'm curious to figure out how this works. I've been testing different components in the evenings this week and I think the problem is with the IC failing to start up for some reason. When the board is plugged in there is no standby voltage.

                                            Then today it randomly sprung to life like a zombie but shortly died thereafter. I have no idea why it would have done that and its the first time I've seen it running. I discharged capacitors on the board last night, then it was sitting today....
                                            02-07-2025, 05:13 PM
                                          • Tynan Dill
                                            Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                                            by Tynan Dill
                                            I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                                            Upon bringing it home and plugging it up, it showed a standby light.

                                            I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                                            The screen seems to blackout and stay black, but with a flashlight I can see the display.

                                            With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                                            Assuming...
                                            11-22-2024, 01:46 PM
                                          • AleMonti
                                            LG 55EG910V - no power and no standby light
                                            by AleMonti
                                            Hi everyone,
                                            I'm trying to troubleshoot and repair this old LG OLED curved TV, model 55EG910V.
                                            I did some basic troubleshooting and reviewed most related posts here, but I wasn't able to isolate the issue.

                                            The TV shut itself off during playback and never came back to life - the standby light remains off. My dad claims that it has happened a few times in the past but the issue resolved itself after some time. Not this one.

                                            After checking the basics I did the following:
                                            • I measured all voltages and as expected the only active supply is the 3.5V standby. It
                                            ...
                                            11-04-2024, 05:02 PM
                                          • Vahalaru
                                            Visio E600i-B3 will not power on.
                                            by Vahalaru
                                            [B]Background[/B]
                                            I recently fixed our Samsung black screen of death by watching YouTube videos and reading through previous threads. Removed a few ceramic capacitors and fixed a short on the back side of the tcon board. So my father and law asked me if I could try to fix his visio. He said that it wouldn't power on. When he first brought it to me I plugged it in and there was a standby light. When I hit the power button the TV booted up and everything worked. I hit the power button again and then I saw what he ment. Since then I have not been able to get it to power on or have a standby...
                                            08-24-2021, 07:23 PM
                                          • rabbituk
                                            Sony HCD BX7700dbi CMT flashing standby
                                            by rabbituk
                                            I have got a Sony HCD-BX7700dbi that isn't worth a lot but I'm keen to learn how to repair and would appreciate some help with my train of thought. The protection circuit is kicking in and the standby light is blinking. It goes into protection mode within a second of powering it on.

                                            So far the relay on the power board that enables the main transformer clicks on and then off when powering on the unit. Looking at the schematics, the permanently enabled power rail called 'unreg sub' provides about 13.5VDC. Where the power comes into the main board on connector CN303, there is a diode...
                                            02-11-2025, 05:05 PM
                                          • Loading...
                                          • No more items.
                                          Working...