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Norcent LM-2265W with Blank Display

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    #1

    Norcent LM-2265W with Blank Display

    Hello all!

    I have another LCD with a problem. This one has a blank display.

    When the monitor is powered up with no computer connected, the display shows a No Signal message after several seconds and then goes blank. The power light also changes to amber.

    With a computer connected, the display remains blank and the power light remains green. I have shined a flashlight on the screen and I am not able to see any image.

    I have checked for voltages at different points and everthing seems normal but without a schematic I am not sure.

    Any ideas where to look?

    Thank you.
    Attached Files
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    #2
    Re: Norcent LM-2265W with Blank Display

    Originally posted by tervel12 View Post
    I have checked for voltages at different points and everthing seems normal but without a schematic I am not sure.
    On the logic card, there is a voltage regulator at I104. With respect to ground, list the voltages on all pins.

    Please also report the part number of I104.
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      #3
      Re: Norcent LM-2265W with Blank Display

      Check the display resolution setting on your computer. Many monitors go black if the signal resolution exceeds the capabilities of the monitor.

      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

        #4
        Re: Norcent LM-2265W with Blank Display

        Did you try repairing the logic board at all? Looks like two transistors have been resoldered/replaced? Circled in photo.
        Attached Files

        Comment

          #5
          Re: Norcent LM-2265W with Blank Display

          Originally posted by retiredcaps View Post
          On the logic card, there is a voltage regulator at I104. With respect to ground, list the voltages on all pins.

          Please also report the part number of I104.
          I will check the voltages when I get home. However I did note that the middle leg is missing on that regulator. The part number is 1084-33 0712HL.

          Originally posted by PlainBill View Post
          Check the display resolution setting on your computer. Many monitors go black if the signal resolution exceeds the capabilities of the monitor.

          PlainBill
          The display resolution is set to 1024x768 and displays fine on a working 15" monitor.

          Originally posted by jetadm123 View Post
          Did you try repairing the logic board at all? Looks like two transistors have been resoldered/replaced? Circled in photo.
          I removed both transistors to test them out of circuit. So the poor soldering is my handywork. (it's a bitch soldering those little things)

          Thanks.

          Comment

            #6
            Re: Norcent LM-2265W with Blank Display

            Originally posted by retiredcaps View Post
            On the logic card, there is a voltage regulator at I104. With respect to ground, list the voltages on all pins.

            Please also report the part number of I104.
            Pin 1 is 0V
            Pin 2 is 3.3V
            Pin 3 is 4.7V

            Comment

              #7
              Re: Norcent LM-2265W with Blank Display

              Originally posted by tervel12 View Post
              Pin 1 is 0V
              Pin 2 is 3.3V
              Pin 3 is 4.7V
              Looks like the 3.3V output is good. Input should be closer to 5V, but 4.7V will do.

              Did you verify that the video cable used to connect your pc to the monitor is good?

              When you say the screen is "blank", I'm assuming that the backlights are also off?

              Comment

                #8
                Re: Norcent LM-2265W with Blank Display

                The cable is good. I have used it on other monitors with no problems.

                The screen backlight comes on briefly when it displays the 'No Signal' message and then it goes out.

                When the computer is connected, there is no backlight or image that I can see.

                Why does I104 not have a pin #2 connected to the board?

                I have removed the caps on the logic board and tested them and they all check out fine.

                Comment

                  #9
                  Re: Norcent LM-2265W with Blank Display

                  Originally posted by tervel12 View Post
                  I have removed the caps on the logic board and tested them and they all check out fine.
                  How? Did you use an ESR meter?
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                  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.

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                  Comment

                    #10
                    Re: Norcent LM-2265W with Blank Display

                    Originally posted by tervel12 View Post
                    The cable is good. I have used it on other monitors with no problems.

                    The screen backlight comes on briefly when it displays the 'No Signal' message and then it goes out.

                    When the computer is connected, there is no backlight or image that I can see.

                    Why does I104 not have a pin #2 connected to the board?

                    I have removed the caps on the logic board and tested them and they all check out fine.

                    The middle pin of I104 is internally connected to the metal tab on the back of the regulator.

                    You should at least be getting an image, since the the logic board is getting 5V.

                    Comment

                      #11
                      Re: Norcent LM-2265W with Blank Display

                      Originally posted by retiredcaps View Post
                      How? Did you use an ESR meter?
                      I do not have an ESR meter. I removed the caps and put them on my DMM with the ohms set to 20K. I can watch the resistance climb as though the cap is charging with the leads connected to the right poles. If I reverse the leads, it shows an infinite reading immediately.

                      Originally posted by jetadm123 View Post
                      The middle pin of I104 is internally connected to the metal tab on the back of the regulator.

                      You should at least be getting an image, since the the logic board is getting 5V.
                      Good to know about I104.

                      Since there is no image from either the DVI or VGA line, could the main IC on the logic board be bad?

                      The only image I ever see is the No Signal message with no input connected.

                      Thanks.

                      Comment

                        #12
                        Re: Norcent LM-2265W with Blank Display

                        Originally posted by tervel12 View Post
                        I do not have an ESR meter. I removed the caps and put them on my DMM with the ohms set to 20K. I can watch the resistance climb as though the cap is charging with the leads connected to the right poles. If I reverse the leads, it shows an infinite reading immediately.



                        Good to know about I104.

                        Since there is no image from either the DVI or VGA line, could the main IC on the logic board be bad?

                        The only image I ever see is the No Signal message with no input connected.

                        Thanks.
                        Yes, I'm starting to think something is wrong with the scaler chip (main chip).

                        Comment

                          #13
                          Re: Norcent LM-2265W with Blank Display

                          Any way to test it?

                          Also, is it replaceable?

                          Thanks.

                          Comment

                            #14
                            Re: Norcent LM-2265W with Blank Display

                            Originally posted by tervel12 View Post
                            Any way to test it?

                            Also, is it replaceable?

                            Thanks.
                            No way to replace the scaler chip. As for the way you tested the caps, it will give very limited results at best. Since you had them out, it would have been best if you had just replaced them all with Panasonic FM or FC series caps.

                            Comment

                              #15
                              Re: Norcent LM-2265W with Blank Display

                              Originally posted by jetadm123 View Post
                              No way to replace the scaler chip. As for the way you tested the caps, it will give very limited results at best. Since you had them out, it would have been best if you had just replaced them all with Panasonic FM or FC series caps.
                              Aside from trying the caps, then this thing is pretty much trash I guess?

                              Comment

                                #16
                                Re: Norcent LM-2265W with Blank Display

                                Originally posted by tervel12 View Post
                                Aside from trying the caps, then this thing is pretty much trash I guess?
                                Not really. You can keep an eye out for a logic card on ebay. Or, try selling it as-is through craigslist or ebay.

                                Comment

                                  #17
                                  Re: Norcent LM-2265W with Blank Display

                                  Originally posted by jetadm123 View Post
                                  Not really. You can keep an eye out for a logic card on ebay. Or, try selling it as-is through craigslist or ebay.
                                  I have searched both but have not been able to find any other Norcent monitors. I have found some TVs, but it seems like it is a pretty scarce brand.

                                  Off to ebay then! Maybe somebody out there needs the screen.

                                  Thanks.

                                  Comment

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