AOC Envision LE24H067 Wont turn on at all

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • kaks
    Member
    • Nov 2011
    • 25

    #1

    AOC Envision LE24H067 Wont turn on at all

    Hello im new to this forum so please if im in the wrong section direct me please.

    OK so here i go?

    I picked up this LED tv at a flea market thinking it would be an easy fix but i have spent over 2 days trying to figure out the problem but cant seem to find it.

    Syntoms: When i plug the power cable to the wall outlet i just see the standby light blink once and then stays of and never turns on again. I dont hear any kind of sound or any other thing.


    Things done: I have been focusing on the Power board thinking this is the problem but i have found nothing.

    I used my multimeter to test out the voltage outputs pins of the power board and this are the results of the printed volts on the board.

    Labeled

    (GRD) = ok
    (GRD) = ok
    (+16v) = ok i get 16.2v
    (+16v) = ok i get 16.2v
    (+5.2) = ok i get 5.2v
    (+5.2) = ok i get 5.2v

    There is a pin called 0/F and another named DIM. those are not outputting any voltage

    the backlight pin volts dont match the voltage labeled could this be the Problem?

    labeled

    (42.9v) I get 16v on my multimeter
    (42.9v) I get 16v on my multimeter


    All caps seem to be fine from my view there are no signs of bubble heads or drains.

    There is a Yellow transformer that has one side all legs are like burned with some yellow stuff. Could that be bad? would i still be getting voltage out of the power board like a i do if that transformer was bad?

    I Have attached some pics to give you guys an idea of my situation.

    Hope you guys can help this newbbie

    All suggestions are welcomed. Thank you
    Last edited by kaks; 11-12-2011, 06:19 PM. Reason: add photos
  • kaks
    Member
    • Nov 2011
    • 25

    #2
    Re: AOC Envision LE24H067 Wont turn on at all

    this are the fotos
    Attached Files

    Comment

    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA

      #3
      Re: AOC Envision LE24H067 Wont turn on at all

      1. Borrow or buy a better camera.

      2. Use the better camera to take Several pictures - a picture of the top of the power supply, a picture of the bottom side of the power supply, one of the top side of the main board, and one over-all shot of the back of the TV.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

      Comment

      • kaks
        Member
        • Nov 2011
        • 25

        #4
        Re: AOC Envision LE24H067 Wont turn on at all

        Here are the better pics thank you
        Attached Files

        Comment

        • Mad_Professor
          A Mech Warrior
          • Feb 2011
          • 1587

          #5
          Re: AOC Envision LE24H067 Wont turn on at all

          Can you also list the capacitor values, please?

          Example:
          Series, Temp Capacitance, Voltage, diameter and height, lead spacing if possible
          KZG, 105*C, 1000uf, 35v, 12.5 x 20mm, 5mm

          Comment

          • retiredcaps
            Badcaps Legend
            • Apr 2010
            • 9271

            #6
            Re: AOC Envision LE24H067 Wont turn on at all

            Schematic at (by searching for 42.9V envision)

            Last edited by retiredcaps; 11-12-2011, 08:13 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

            • kaks
              Member
              • Nov 2011
              • 25

              #7
              Re: AOC Envision LE24H067 Wont turn on at all

              Ok the brown capacitors on the top left are:

              2x elite 120uf 63v Ep(m)105 degrees pet (c)1016
              1x elite 270uf 25v Eh(m)105 degrees pet (c)1016


              the capacitors in the top middle of board are

              brown 1x elite 270uf 25v Eh(m)105 degrees pet (c)1016
              orange 2x elitegp 68uf 25v 120
              orange 1x elitegp 470uf 10v 120
              black 1x elite 470uf 16v

              and the one farthest to the right is a

              1x elite 47uf 35v 105 degrees c

              and the last 2 long ones on the bottom right are

              2x 100uf 220v pz(m)105 degrees c

              this is all the information that reads each capacitor

              1x 2x etc. means number of capacitor with does values thank you

              hope someone can help me please.

              Comment

              • PlainBill
                Badcaps Legend
                • Feb 2009
                • 7034
                • USA

                #8
                Re: AOC Envision LE24H067 Wont turn on at all

                retiredcaps, thanks for the link to the schematic. That may help make up for the lack of good pictures.

                Kakz, The pictures don't quite cut it. The schematics that retiredcaps found help, but I'm getting a sore neck trying to read the schematics sideways. Yes, the absence of the 42.9 volt rail is significant.

                Possible suspects are IC904, Q920, D913, R951, and the enable signal at IC904, pin 13. Of these, IC904, pin 13 is most likely the problem. Verify that pin 1 of CN902 reads 0 volts. If it does, the problem is on the main board. If it reads 5 volts, the problem is on the power supply card.

                PlainBill
                For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                Comment

                • kaks
                  Member
                  • Nov 2011
                  • 25

                  #9
                  Re: AOC Envision LE24H067 Wont turn on at all

                  Ok i verified pin 1 of CN902 and it reads 0v i did the test using just the power board connected to wall i disconnected the digital video board . please guide me what should i do next i have attached some new pics please see them. Note that on the connector of the digital video board there are 2 pins that say 24v and those two pins go connected to the powerboard and on the powerboard it is label 16v and i tested the voltage and i get 16.45 v
                  Attached Files

                  Comment

                  • PlainBill
                    Badcaps Legend
                    • Feb 2009
                    • 7034
                    • USA

                    #10
                    Re: AOC Envision LE24H067 Wont turn on at all

                    Originally posted by kaks
                    Ok i verified pin 1 of CN902 and it reads 0v i did the test using just the power board connected to wall i disconnected the digital video board . please guide me what should i do next i have attached some new pics please see them. Note that on the connector of the digital video board there are 2 pins that say 24v and those two pins go connected to the powerboard and on the powerboard it is label 16v and i tested the voltage and i get 16.45 v
                    You will have to do the test with the main board connected. It took some time to study the schematic; it's poorly drawn and loaded with errors. Apparently the same raw board is used to make at least three different finished power supply / LED drivers. Two of them have extensive circuitry to drive LEDs. The version you have is quite simple. The On/Off signal comes from the main board. When it goes high a DC-DC converter starts which boost 16.2 V to 42.9V. The DIM signal, 42.9V, and GND are sent directly to the LED strips.

                    I suggest hooking a signal source (DVD player, video game) to the TV inputs, turning the TV on, and stepping through the inputs until you hear the audio. Sometimes you can see an image if you shine a bright light on the screen (I've never been able to get this to work). If you can't hear the audio, the main board is definitely bad. I wouldn't be concerned about the mismatched labels; this is obviously a lash-up design.

                    PlainBill
                    Last edited by PlainBill; 11-13-2011, 06:36 AM.
                    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                    Comment

                    • kaks
                      Member
                      • Nov 2011
                      • 25

                      #11
                      Re: AOC Envision LE24H067 Wont turn on at all

                      Hello thanks for your time. Well i did the test with the main board connected and i still dont get any voltage reading from Pin 1 of CN902.
                      I also tested the tv connecting a dvd player and i couldnt hear anything.

                      Does this all mean I have a bad video logic board?
                      is there a way i can fix it?


                      What is my next step please?

                      Comment

                      • kaks
                        Member
                        • Nov 2011
                        • 25

                        #12
                        Re: AOC Envision LE24H067 Wont turn on at all

                        Ok here is a pic of of the connector on the main logic video board this is where the power,volume, source select bar is connected and also the standby light and the remote sensor.

                        I tested the pins with my multimeter and they read like this

                        pwr= reads 3.3
                        sensor = its not in use
                        key = reads 3.3
                        3.3v = reads 3.3v the other labeled 3.3v its not in use
                        IR = 3.2
                        LED_B = reads 0v no volts
                        LED_R = its not in use

                        I did a little test i Measured the voltage on PWR and when i press the power button it goes from 3.3 to 0v is that normal?

                        if you guys need more pics please tell me thankyou all for your help.
                        Attached Files

                        Comment

                        • tom66
                          EVs Rule
                          • Apr 2011
                          • 32560
                          • UK

                          #13
                          Re: AOC Envision LE24H067 Wont turn on at all

                          Try pressing the buttons on the board; does the KEY voltage vary?
                          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

                          • PlainBill
                            Badcaps Legend
                            • Feb 2009
                            • 7034
                            • USA

                            #14
                            Re: AOC Envision LE24H067 Wont turn on at all

                            Originally posted by kaks
                            Hello thanks for your time. Well i did the test with the main board connected and i still dont get any voltage reading from Pin 1 of CN902.
                            I also tested the tv connecting a dvd player and i couldnt hear anything.

                            Does this all mean I have a bad video logic board?
                            is there a way i can fix it?


                            What is my next step please?
                            The approach that is most likely to succeed is to replace the main board. There is a white label with a bar code on it, the top line is partially obscured, it most likely is the part number of the board. Google that number.

                            PlainBill
                            For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                            Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                            Comment

                            • kaks
                              Member
                              • Nov 2011
                              • 25

                              #15
                              Re: AOC Envision LE24H067 Wont turn on at all

                              Ok i tested the voltage on the KEY pin as TOM said and YES the voltage varies when i press the volume, channel, menu and source buttons BUT Voltage does not varie when i press the Power key. is this OK?

                              Comment

                              • tom66
                                EVs Rule
                                • Apr 2011
                                • 32560
                                • UK

                                #16
                                Re: AOC Envision LE24H067 Wont turn on at all

                                Originally posted by kaks
                                Ok i tested the voltage on the KEY pin as TOM said and YES the voltage varies when i press the volume, channel, menu and source buttons BUT Voltage does not varie when i press the Power key. is this OK?
                                Does the PWR voltage change when the power button is pressed?
                                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

                                • tom66
                                  EVs Rule
                                  • Apr 2011
                                  • 32560
                                  • UK

                                  #17
                                  Re: AOC Envision LE24H067 Wont turn on at all

                                  Originally posted by PlainBill
                                  The approach that is most likely to succeed is to replace the main board. There is a white label with a bar code on it, the top line is partially obscured, it most likely is the part number of the board. Google that number.

                                  PlainBill
                                  This is a good approach, but a main board can be expensive. It would be good to see if it can be repaired first.
                                  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

                                  • kaks
                                    Member
                                    • Nov 2011
                                    • 25

                                    #18
                                    Re: AOC Envision LE24H067 Wont turn on at all

                                    No the voltage does not change i know there is voltage on the pwr it reads 3.2v
                                    so what should be my first step to test the main video logic board? thank you

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK

                                      #19
                                      Re: AOC Envision LE24H067 Wont turn on at all

                                      Originally posted by kaks
                                      No the voltage does not change i know there is voltage on the pwr it reads 3.2v
                                      so what should be my first step to test the main video logic board? thank you
                                      First I would like you to post a picture of the switch board; both sides. It's possible the button is faulty. I have seen cases where the power button is stuck down which holds the TV in a standby mode or permanently turns it off. Or maybe the button controls the standby.

                                      If that proves fruitless then the main board becomes the suspect.

                                      The fact that you get a brief standby light is encouraging. Usually a bad main board causes either no standby, or permanent standby, or sometimes the TV will exit standby (e.g. with a blue LED) but will stay there and will not turn off or show a picture.
                                      Last edited by tom66; 11-13-2011, 03:24 PM.
                                      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

                                      • kaks
                                        Member
                                        • Nov 2011
                                        • 25

                                        #20
                                        Re: AOC Envision LE24H067 Wont turn on at all

                                        So why am i not getting any Standby light when i plug the tv to the wall? if i press the volume channel keys there is power. the only thing it does is that it blinks as soon as i plug it in to the wall.

                                        Comment

                                        Related Topics

                                        Collapse

                                        • dj8452000
                                          How To Test a P-channel Trench Mosfet Using A Multimeter In Diode Mode
                                          by dj8452000
                                          I am new to electronics and I'm understanding most of what I'm reading but I have a mosfet on my board that I've identified as a P-channel Trench Mosfet. I haven't a clue how to test this and what I should expect to see with the multimeter probes. I am hoping someone with years more experience than myself can help me understand how to use a multimeter to read this. Please look at the drawing I have attached to this and can you try to explain to me what I should be doing with my multimeter in diode mode and what results I should expect from a good mosfet?...
                                          02-18-2025, 08:28 AM
                                        • trex66
                                          Craftsman 82345 Multimeter broke!
                                          by trex66
                                          My daily carry just stopped working only me. Started last week with the voltage flickering. Found one lead was broken and I ordered new ones. New leads didn't change anything, it displays “-1” on all settings but on continuity will give the tone when touching. Checked battery and found the fuse blown. Replaced fuse but same results. Cleaned the dial and led display and its parts. Board looks nice and clean no burned or broken components. Nothing traumatic happened to this multimeter I put it aside when I found the lead broken and didn't touch it until I got the neAnyone have any ideas what's...
                                          03-04-2025, 04:26 PM
                                        • Sofian75
                                          Things not to do with a multimeter?
                                          by Sofian75
                                          I started to learn laptop repair a few weeks ago, since then I ve ordered several dead laptops to try to fix them and learn.
                                          I fixed some of them and some I ve made things worse by blowing components.
                                          Every time while taking measurements with my multimeter.

                                          Yesterday I was working on a dell laptop motherboard, I was checking the charge IC for short in diode mode and it killed the chip.

                                          So my question is are there things I should not do with my multimeter?
                                          Or measurements I should do only with the charger and battery unplugged?...
                                          06-27-2024, 05:13 AM
                                        • max_smart
                                          T430 laptop doesn't power on- please help me troubleshoot w/multimeter (fixing for fun)
                                          by max_smart
                                          Hi all,

                                          First off, this forum really helped me out by advising me to cut some ribbon connectors to the LCD panel in order to fix a 70" TV (lots of threads on Sharp TVs with this issue). I didn't believe that it could work, but it did.

                                          Now I've been encouraged to try to diagnose something quite a bit more complicated. That is an old T430 motherboard. I work on a college campus so I have access to pretty decent tools. I found the schematic for the motherboard on the site, and have been following traces and taking DC measurements from things. I also don't mind...
                                          06-01-2024, 03:27 PM
                                        • antoniu200
                                          Why does my Uni-T multimeter not measure anything?
                                          by antoniu200
                                          Hi! So, a couple of months ago, I got tired of me watching my movies and when someone flips a certain switch in the house, my Blu-Ray to stop working for a second, then come back on (the TV being fine, mind you, connected both at the same outlet). So, I took my multimeter (Uni-T UT33B) and tried to measure the voltage of my outlet when that switch is flipped. Dumb me, I set the multimeter for DC Voltage, while connecting the red cable to the Unfused connection. Of course, both the fuses in the multimeter and in my house blew.

                                          Now, I replaced the fuse in the multimeter, but it still...
                                          11-11-2019, 07:40 AM
                                        • Loading...
                                        • No more items.
                                        Working...