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    #1

    HP w1907 LCD Monitor - white screen

    I have a HP w1907 LCD Monitor that powers up, but displays a blank white screen only. From my experience on Laptop repair, it's always the screen or the cable, but in rare cases it can be a motherboard issue. This appears to be a typical LCD screen failure.

    The LCD monitor turns on and off OK. I checked several components on the logic board as well as the voltages coming off the power board - I believe everything looked OK from a basic standpoint. If you need this info in more detail, let me know. I researched the forums a litte and found a fuse can cause this on the LCD panel board. I found a fuse next to the connector and checked it - ohmed out to some stange reading, it's not 0, so it's open and bad.

    I understand replacing the fuse probably won't solve the problem completely. What else should I check, or does the panel need to be replaced?

    Attached are pictures!

    Ideas appreciated!
    Attached Files
    Last edited by Rolin; 02-26-2012, 01:24 AM.
    Tags: None
    #2
    Re: HP w1907 LCD Monitor - white screen

    Hi -Have you read this post www.badcaps.net/forum/showthread.php?t=18236
    You probably need Momaka or another panel expert to help. As in the link I can only suggest you make sure the cable contacts are cleaned.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment

      #3
      Re: HP w1907 LCD Monitor - white screen

      Originally posted by Rolin View Post
      What else should I check, or does the panel need to be replaced?
      See if IC3, a voltage regulator, is shorted or not. Number the pins 1, 2 and 3. Test for a short between pins 1-2, 1-3, and 2-3. Any reading under 30 ohms suggests a possible short and warrants desoldering and retesting out of circuit.
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        #4
        Re: HP w1907 LCD Monitor - white screen

        In addition to the voltage regulator retiredcaps mentioned, there are a number of caps that are possible suspects. They are CD1, CD3, CD4, CD7, CD8, CD9, CD10, CD11. In addition, check SD1. And sometimes the fuse just blows.

        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

          #5
          Re: HP w1907 LCD Monitor - white screen

          IC3 doesn't appear to be shorted. Pins 1-2 is .624KOhms, 1-3 is 1.53KOhms, 2-3 is 2.2KOhms.

          Plainbill, I checked all the caps you mentioned for shorts - none were shorted. I don't know how to really checks caps to see if they're in spec, but they don't appear to be shorted.

          Don't know how to check SD1 - I metered the leads a little and there are no shorts I guess.

          Could I be one of the lucky ones where this is only a fuse? I have no idea how to find the value for this fuse, and I'm a little afraid to jump accross it - unless you guys think it's OK to try!

          Comment

            #6
            Re: HP w1907 LCD Monitor - white screen

            Selldoor, I did read that thread and the youtube link. Interesting how common it's needed on one particular model.

            I've reseated connectors on LCD screens in laptops often - it's the first thing I try. It does work sometimes. If a reseat works, I usually will clean with alcohol or use the eraser trick. I learned the eraser trick at Control Data and Unisys back in the 80's - very common fix back then on larger computer equipment with lots of boards! The board contacts needed cleaning much more often back then for some reason - I don't think they used gold contacts as much or something like that.. don't remember why exactly. It's a good trick on cheaper RAM modules too!

            Comment

              #7
              Re: HP w1907 LCD Monitor - white screen

              I have been looking for a fuse value but failed. I see Tom66 soldered his over but blew other components. I have heard of others trying a very thin wire then if it did work start with a low amp and work up. Some solder in a fuse holder to make use of cheaper fuses. I might even have read of someone using a light bulb but not sure about that. Ill see if I can find it.
              In looking I did see that someone with white screen had decided it was a transistor on the video board but unfortunately didnt say which and didnt confirm it. going on from that if you can post a better pic of your video board we may be able to spot a burn or others may suggest which transistors could cause white screen. Q302? I301?
              I have what I think is the schematic and that might help.
              Attached Files
              Please upload pictures using attachment function when ask for help on the repair
              http://www.badcaps.net/forum/showthread.php?t=39740

              Comment

                #8
                Re: HP w1907 LCD Monitor - white screen

                Originally posted by Rolin View Post
                I have no idea how to find the value for this fuse, and I'm a little afraid to jump accross it - unless you guys think it's OK to try!
                Your photo resolution is a bit low, but I think I can see a letter on F1. The letter will tell you the fuse amperage required.
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                Comment

                  #9
                  Re: HP w1907 LCD Monitor - white screen

                  Update:

                  Selldoor, I'm pretty sure I also read somewhere that someone used a light bulb in place of the fuse -If it lights, then you have a short somewhere! I can understand how it could work, but I've never tried it! Thanks for finding those schematics - but in the end I didn't need them.

                  RetiredCaps, it's a "k" for 1.5 amp. I have some old laptop LCDs laying around with cracked screens, etc - I use them to test for backlight issues on laptops like I've read you do as well. Anyway, I found a "k" on one of them! Surfacemount soldering is tricky, but I managed to remove the old one and solder in the new one. The darn thing works. I can't believe it was such an easy fix - a little fuse on the LCD panel. This was a fairly nice monitor a few years ago, and quite frankly it still is very very nice - great picture. It's been sitting around for at least 3 or 4 years until I finally "got around to it".

                  Thanks for the help guys. I'm on to the next one!

                  Comment

                    #10
                    Re: HP w1907 LCD Monitor - white screen

                    Originally posted by Rolin View Post
                    Selldoor, I'm pretty sure I also read somewhere that someone used a light bulb in place of the fuse -If it lights, then you have a short somewhere! I can understand how it could work, but I've never tried it!
                    http://www.repairfaq.org/samnew/tvfaq/tvtslbt.htm
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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

                      #11
                      Re: HP w1907 LCD Monitor - white screen

                      its the fuse on the lcd.....F101 and FL101

                      Comment

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