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RCA L42WD22 No Picture

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    #1

    RCA L42WD22 No Picture

    Hi

    I was given a 42" LCD L42WD22 from a friend to see if I could fix it... I have had no luck thus far. Here's the breakdown.

    Symptoms

    - No Picture at all (black screen) when TV is turned ON

    - No clicking or hissing noises when TV is turned ON

    - TV powers ON (Green LED Constant)

    - Sound works

    - No standby LED when TV is OFF (not sure if this model has a standby light)

    Tests I've Run

    - Visual check for bad capacitors was negative (no bulging or popping)

    - Visual check for cracks in circuit board was negative


    I am very new to LCD repair and only attempted this because I have successfully repaired my Samsung LCD by replacing the bad capacitors I found.

    I am going to be checking for bad solder (cold solder) joints but I'm not sure where to focus my search.

    Has anyone else had problems of this nature?
    Last edited by Doming0; 09-20-2010, 01:43 AM.
    Tags: None
    #2
    Re: RCA L42WD22 No Picture

    1. Is there any flash of light from the backlights (best viewed from the back of the TV with the back removed)?

    2. Have you tried shining a flashlight on the screen to see if a display is present when power up?

    Summary: There are three possible failures.

    1. A failure in the main board.

    2. A failure in the LCD panel / Tcon

    3. A failure in the inverter / backlight system. This could be as simple as a blown fuse.

    As has been repeated countless times, one picture is worth a thousand words. Links to suggestions on posting pictures are in my signature.

    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

      #3
      Re: RCA L42WD22 No Picture

      Sorry, no pictures yet.

      BUT

      I have found 3 blown capacitors. 2 out of 2 on the MAIN and 1 out of 2 on the SLAVE LCD Board.

      They are marked V9A PET. I am in the process of tracking down replacements. Would Radio Shack carry such a capacitor?

      Comment

        #4
        Re: RCA L42WD22 No Picture

        Originally posted by Doming0 View Post
        They are marked V9A PET. I am in the process of tracking down replacements. Would Radio Shack carry such a capacitor?
        You will likely need low ESR capacitors for replacements. Radio Shack does not carry these types of caps.

        You will need to find out the uF, voltage, height and diameter for these caps. If you list your country, members can then suggest suitable vendors.
        Last edited by retiredcaps; 09-20-2010, 11:04 AM. Reason: added height and diameter
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        Comment

          #5
          Re: RCA L42WD22 No Picture

          The ratings are...

          35 V
          470 Uf
          105* C (M)

          I live in Canada.

          Thanks =)

          Height = 3/4"
          Diameter = less than 1/2"
          Last edited by Doming0; 09-20-2010, 11:26 AM.

          Comment

            #6
            Re: RCA L42WD22 No Picture

            Originally posted by Doming0 View Post
            The ratings are...

            35 V
            470 Uf
            105* C (M)

            I live in Canada.

            Thanks =)

            Height = 3/4"
            Diameter = less than 1/2"
            Hmm, Canada. You should be using metric. So for 10mm x 20 mm cap, see Panasonic FM at ca.digikey.com

            http://ca.digikey.com/scripts/DkSear...name=P12415-ND

            Or United Chemi-con KZE

            http://ca.digikey.com/scripts/DkSear...me=565-1694-ND

            Digikey charges $8 USD for s/h to Canada.

            If you have a local electronics store, ask around for

            Panasonic FM, United Chemi-con KZE or any of the caps listed at

            https://www.badcaps.net/forum/showthread.php?t=2280

            PS. I purchased 20 (twenty) KZH United Chemi-con 470uF 35V caps off ebay for $5 total (free shipping) and they were geniune (not fake). Of course, it took 4 weeks to arrive, but seeing how I got 20 quality caps for $3 USD less than the price of digikey shipping, I was willing to wait.
            Last edited by retiredcaps; 09-20-2010, 11:48 AM. Reason: ebay comment
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            Comment

              #7
              Re: RCA L42WD22 No Picture

              I should qualify the ebay comment.

              The caps are certainly look authentic with proper bung, vent configuration, lettering, and date code.

              But I have NO ESR or capacitance meter to verify the specifications. Nor do I have a way of authenticating the seller as a United Chemi-con distributor, but I have used the caps and they seem to work fine (including the one I am using to post this).

              It is reasonable to assume that counterfeits in the future will get better and better.
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              Comment

                #8
                Re: RCA L42WD22 No Picture

                Thank you for your research, it is greatly appreciated. I will look into which method will get me the parts fastest.

                BTW - Judging by the info in my original post, does it sound feasible that the blown caps are the culprit or just another symptom?

                Also, I know that the blown caps had a voltage rating of 35 V. I assume that it would be possible to up this to 50 V to possibly increase longevity... am I wrong?
                Last edited by Doming0; 09-20-2010, 04:05 PM.

                Comment

                  #9
                  Re: RCA L42WD22 No Picture

                  Originally posted by Doming0 View Post
                  Thank you for your research, it is greatly appreciated. I will look into which method will get me the parts fastest.

                  BTW - Judging by the info in my original post, does it sound feasible that the blown caps are the culprit or just another symptom?

                  Also, I know that the blown caps had a voltage rating of 35 V. I assume that it would be possible to up this to 50 V to possibly increase longevity... am I wrong?
                  You are wrong. The caps did not fail because they were operating at a voltage higher than designed. The failed because they could not tolerate the surge current in the SMPS power supply. In simple terms, they were garbage.

                  It is relatively easy to build caps that meet the low ESR specs required when they are new. It is not so easy to build caps that will still meet those specs after 2, 4, or 6 or more years of service. Brands such as Capxon, Elite, Sam Young, etc are known to fail early and spectacularly. Brands such as Rubicon, United Chemicon, Panasonic, Nichicon and a few others are known to last a long time. Given the time and labor involved in replacing the caps, spending a few dollars more (depending on the supplier, you may be spending a few dollars less!!!) for high quality caps. My favorite is Panasonic FM series, but I will readily use other brands and series from the Good Caps list (see my signature for the link).

                  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

                    #10
                    Re: RCA L42WD22 No Picture

                    Ok, cool. That helps clear that up, I will purchase matching ratings but better brand... thank you.

                    Now, please be patient with me since I is a noob and will ask simple questions.

                    The capacitors I must replace are SMD mounted (soldered on top of the board and lying on their side instead of straight up.) and I have never soldered anything on the top side of the board before. Are there any major differences I should be aware of?

                    Also, I know that there are different "families" of capacitors and I just want to make sure I'm getting the right replacement. I tried to take a picture but apparently my camera is all about being blurry and craptastic at best. (Yes I did read the taking good pic's tutorial but my camera is a 4 MP POS.

                    Comment

                      #11
                      Re: RCA L42WD22 No Picture

                      Originally posted by Doming0 View Post
                      The capacitors I must replace are SMD mounted (soldered on top of the board and lying on their side instead of straight up.) and I have never soldered anything on the top side of the board before. Are there any major differences I should be aware of?
                      Since you don't have pictures, I assume you are talking about non through hole? If you are soldering electrolytic caps, then you will have to clip the leads to the correct length before soldering. It might help to order a spare or two if you make a mistake.

                      Also, I know that there are different "families" of capacitors and I just want to make sure I'm getting the right replacement.
                      PCBONEZ talks about choosing the right series or "families" as you call it ...

                      https://www.badcaps.net/forum/showpo...47&postcount=3
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                      Comment

                        #12
                        Re: RCA L42WD22 No Picture

                        Originally posted by Doming0 View Post
                        Ok, cool. That helps clear that up, I will purchase matching ratings but better brand... thank you.

                        Now, please be patient with me since I is a noob and will ask simple questions.

                        The capacitors I must replace are SMD mounted (soldered on top of the board and lying on their side instead of straight up.) and I have never soldered anything on the top side of the board before. Are there any major differences I should be aware of?

                        Also, I know that there are different "families" of capacitors and I just want to make sure I'm getting the right replacement. I tried to take a picture but apparently my camera is all about being blurry and craptastic at best. (Yes I did read the taking good pic's tutorial but my camera is a 4 MP POS.
                        I'd really like to see a picture of the board, even if it isn't a picture of your board. I sometimes pretend I have seen everything, but in honest moments I admit that isn't true. I'm not aware of any SMD caps that are mounted lying down. One of the more experienced people here (Wizard) recommends replacing SMD caps with regular caps with their leads formed to fit.

                        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

                          #13
                          Re: RCA L42WD22 No Picture

                          I had to put the TV away until I get the parts in, I'm using the dining room table and had to placate the wife. But I will take actual photo's when I get the parts.

                          Here is a crude drawing of what I'm talking about.

                          http://www.flickr.com/photos/68226295@N00/5012581626/

                          Comment

                            #14
                            Re: RCA L42WD22 No Picture

                            That's not an SMD cap, it's a regular electrolytic cap, lying down & glued to the board.

                            Look underneath, are there definitely no solder holes?

                            Replacement will be easy.

                            Comment

                              #15
                              Re: RCA L42WD22 No Picture

                              Originally posted by Doming0 View Post
                              Here is a crude drawing of what I'm talking about.

                              http://www.flickr.com/photos/68226295@N00/5012581626/
                              Not a bad drawing. You probably mean something like this?

                              https://www.badcaps.net/forum/attach...1&d=1283627061

                              If yes, then my suggestions in post #11 apply.
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                              Comment

                                #16
                                Re: RCA L42WD22 No Picture

                                So I replaced the bad caps plus the matching ones that didn't look bad. Now I have a very very faint picture when I fire it up. Turned off all lights to see if I could see the bulbs lighting through the back. I couldn't see anything but the green power light that comes on like a charm.

                                Hmmmmm....

                                I'm guessing bad inverter. If so, is it cheaper to fix or order replacement?
                                Last edited by Doming0; 09-21-2010, 11:51 PM.

                                Comment

                                  #17
                                  Re: RCA L42WD22 No Picture

                                  Originally posted by Doming0 View Post
                                  If so, is it cheaper to fix or order replacement?
                                  post #2, pictures, pictures, pictures.
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                                  Comment

                                    #18
                                    Re: RCA L42WD22 No Picture

                                    I apologize in advance for the shite photo's.
                                    Attached Files

                                    Comment

                                      #19
                                      Re: RCA L42WD22 No Picture

                                      Forgot to take pics of the inverters.. here they are prior to replacement.
                                      Attached Files

                                      Comment

                                        #20
                                        Re: RCA L42WD22 No Picture

                                        ring the transformers.if ok one has a bad bd9897 chip.

                                        Comment

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