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Gateway FPD1950 NO POWER

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    #1

    Gateway FPD1950 NO POWER

    I have a Gateway PFD1950 LCD Monitor that won't turn on. Once I plug in the power plug, the front power LED flashes one time then dead. The button does nothing - dead.

    I have checked the voltage on the logic board as follows:

    12V 12.04
    12V 12.04
    GND 0
    GND 0
    5V 5.04
    5V 5.04
    GND 0
    N.C. 0 (varys in mv)
    INV 128.6mv
    DIM 2.7V
    LAMP 5.02V

    I also checked the regulator on the logic board 0, 1.8V, 3.371V

    Appreciate any help on this one. Thank you!
    Attached Files
    Last edited by Rolin; 02-17-2012, 01:02 AM.
    Tags: None
    #2
    Re: Gateway FPD1950 NO POWER

    Originally posted by Rolin View Post
    I have a Gateway PFD1950 LCD Monitor that won't turn on
    Umm, this is your 3rd monitor post. You know what type of info we want and the picture format, otherwise, I hit next thread and move on.
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      #3
      Re: Gateway FPD1950 NO POWER

      Sorry, I bumped the wrong key on the keyboard and it posted by accident before I was finished with my info! I was updating when you responded... I was racing to finish before someone caught me! Let me know if you need more info. Thanks

      Pretty tough to troubleshoot a post that simply said "LCD Monitor wont' turn on"!!, huh?

      Comment

        #4
        Re: Gateway FPD1950 NO POWER

        What is up with U203 by the yellow caps on the left board?
        Looks like it's melted into a lump.
        .
        Mann-Made Global Warming.
        - We should be more concerned about the Intellectual Climate.
        -
        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
        - Dr Seuss
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          #5
          Re: Gateway FPD1950 NO POWER

          Originally posted by Rolin View Post
          Pretty tough to troubleshoot a post that simply said "LCD Monitor wont' turn on"!!, huh?
          1) Those posts usually have no replies (at least from me). I waste too much of my time playing 20 questions only to find out they don't have a multimeter or don't want to solder. Or I write out this nice long detailed response in post #2 and they never come back to the forum.

          On the other hand I can easily fix those monitors for the OP if they put $500 into my paypal account.

          2) When you say the power LED is "dead", does it go off? Change color?

          3) My spatial mapping skills are not the best. Which pin on the logic board corresponds to the PWR pin on the power board? Is it the INV?

          4) Is there 5V DC present on the logic board connector to the front keyboard (the blue wire)?
          Last edited by retiredcaps; 02-17-2012, 01:48 AM.
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            #6
            Re: Gateway FPD1950 WON'T TURN ON

            Originally posted by Rolin View Post
            I also checked the regulator on the logic board 0, 1.8V, 3.371V
            What are the readings for U401 (another regulator)?
            Last edited by retiredcaps; 02-17-2012, 04:09 AM.
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              #7
              Re: Gateway FPD1950 NO POWER

              PCBonez, U203 isn't melted. Must be the picture

              Comment

                #8
                Re: Gateway FPD1950 NO POWER

                Retiredcaps,

                Answers to your questions:

                When I plug in the monitor the power LED quickly flashes then it's out - no color. Pressing the power button does absolutely nothing.

                Your question about which pin corresponds to which name is confusing to me because the board layout makes it confusing. I'll try to explain. The power board shows 12V, GND, 5V GND, PWR, BRT - but they aren't aligned with the pins. 6 labels for 11 wires? So I looked on the logic board where they made more sense. I checked to see if the voltages changed order on the Logic board (in case the wires get swapped in the cabling) and the voltages stay in the same order - so the cabling stays in the same order on both the Logic board and the Power board. So to answer your question, I'm sorry but I just can't tell.

                The blue wire for the front panel is 5.04V

                U401 is 5.04V, 0 (missing middle pin), 3.371V

                Comment

                  #9
                  Re: Gateway FPD1950 NO POWER

                  Please post a photo of the bottom of your power board. The mosfets that drive the inverter section need to checked for shorts.

                  Comment

                    #10
                    Re: Gateway FPD1950 NO POWER

                    Originally posted by Rolin View Post
                    The blue wire for the front panel is 5.04V
                    1) See if your front keyboard has any voltages.

                    2) See if the voltages change on the keyboard when you press the on/off button. In particular, see if the on/off switch changes.

                    3) Measure the DC voltages for KEY2, KEY1, LED-AM, and LED-GR as well.

                    U401 is 5.04V, 0 (missing middle pin), 3.371V
                    4) 3.371V is barely within spec according to

                    http://pdf1.alldatasheet.com/datashe...KIA78D33F.html

                    The max is 3.380V. If your multimeter is out of spec, the 3.371V could even be higher making this regulator possibly suspect and bad.
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                      #11
                      Re: Gateway FPD1950 NO POWER

                      The front panel has voltages, every button shows 4.3V unless pressed then it drops to 0 or pretty close.

                      The connector going to the front panel measured at the board is as follows:
                      KEY2 4.33
                      KEY1 4.33
                      LED AM Varies in MV - looks like a capacitor is draining the longer I keep the meter connected
                      LED GR (Same as LED AM)
                      GND 0
                      5V 5.04V

                      I also attached a picture of the back of the Power board.

                      What do you think?
                      Attached Files

                      Comment

                        #12
                        Re: Gateway FPD1950 NO POWER

                        Originally posted by jetadm123 View Post
                        Please post a photo of the bottom of your power board. The mosfets that drive the inverter section need to checked for shorts.
                        Just my 3 cents worth, I agree with jetadm123.The MOSFETS in the inverter area probably need to be checked.
                        If there is a power issue with the LCD and you notice funny things with the Front PLED.
                        The most common issues are going to be bad capacitors, a bad LDO regulator on the logic board or something loading the power supply down.
                        If it is an excessive load causing the problem, a really simple way to diagnose would be to remove loads one at a time from the system.
                        If it is an inverter causing the problem, you could disable the inverter by either removing the inverter fuse or locating a jumper that feeds the inverter and removing it. If you gain control of the front PLED something in the inverter area is causing the problem.
                        You could also remove another load by removing the ribbon from the logic board to the LCD panel, See if the monitor behaves any differently.
                        Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                        Comment

                          #13
                          Re: Gateway FPD1950 NO POWER

                          A couple of questions:

                          I uploaded a bottom view to the power board - jetadm123 mentioned the MOSFET's are on the bottom - I'm not strong on component level (especially smd) components, which are the MOSFET's?

                          Badcaps mentioned that he suspects one of the regulators is a little low at 3.371V. He believes it should be 3.38 or higher. My meter is fairly new and I really don't suspect it uncalibrated - could this regulator be the issue?

                          Alexanna, I disconnected the ribbon cable to the LCD screen - no difference

                          Disconnected all CCFL cables - same issue

                          BTW: I have inspected all caps - they look flat. I understand they can still be faulty, but I wanted to mention it.

                          Are the inverter fuses FB101, FB301 and FB302? You mentioned I should remove to test for changes?

                          I guess this one will be more difficult since I really have limited component level troubleshooting skills. But always ready to learn and follow instructions...
                          Last edited by Rolin; 02-19-2012, 11:14 AM.

                          Comment

                            #14
                            Re: Gateway FPD1950 NO POWER

                            The two mosfets in question are circled in the photo. You'll have to look up the datasheet(s), then test them as follows:

                            With power off, set your meter to 2k ohms and place your probes across:

                            S1-G1
                            S1-D1
                            G1-D1

                            S2-G2
                            S2-D2
                            G2-D2

                            Perform this test for the other mosfet. If you see approx 0 ohms for any of your readings, then you have a short.
                            Attached Files

                            Comment

                              #15
                              Re: Gateway FPD1950 NO POWER

                              Thanks Jetadm,

                              Per the data sheet at

                              measured as follows (buy the way, I'm using a Digital mulitmeter - no 2K setting, it's autoadjusting)

                              S1-G1 open
                              S1-D1 fluctuates like a cap charging - in MOhms
                              G1-D1 Open

                              S2-G2 open
                              S2-D2 fluctuates like a cap charging - in MOhms
                              G2-D2 open

                              They don't appear to be shorted...

                              Comment

                                #16
                                Re: Gateway FPD1950 NO POWER

                                Originally posted by Rolin View Post
                                Badcaps mentioned that he suspects one of the regulators is a little low at 3.371V. He believes it should be 3.38 or higher. My meter is fairly new and I really don't suspect it uncalibrated - could this regulator be the issue?
                                No you misunderstand. According to the datasheet for this regulator, 3.38V is the maximum voltage that it can be in order to be considered good. If it is higher than 3.38V, then it is bad.
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                                  #17
                                  Re: Gateway FPD1950 NO POWER

                                  I understand now, the regulator is at the top of the spec. Even though it is still actually within spec (although darn close) do you think this regulator is causing the problem? Would you replace it?

                                  I'm kind of at a loss as to what to do next. Maybe this one is just too difficult to troubleshoot? Would be open to more suggestions (keeping in mind I'm a newbie to component level troubleshooting) - but I'm a fast learner....

                                  Comment

                                    #18
                                    Re: Gateway FPD1950 NO POWER

                                    Originally posted by Rolin View Post
                                    I understand now, the regulator is at the top of the spec. Even though it is still actually within spec (although darn close) do you think this regulator is causing the problem? Would you replace it?
                                    You can try a replacement and see what happens.
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