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    Gateway LP2407 Power issue

    First of i'd like to say Hello all! First post, and as with most i imagine, it's because i'm in need of some advice. This definitely seems the place to ask.

    From a search i can see that many others have similar issues with this Gateway Screen (Gateway LP2407), one thread in fact is more or less identical, however there isn't a solution reached.

    https://www.badcaps.net/forum/showth...ghlight=LP2407

    First of all, some history.

    I've had the monitor for around 5 years and it's served me nicely. I just figured as it's well out of warranty i may as well try fixing it myself as it's a pretty nice panel to give up on.

    It's never had anything spilt on it, or been dropped or squashed.

    It has always had some strange issues, the main i can think of is the initial small 'Gateway' splash screen that displays when first switched on sometimes didn't fade off properly, and hangs there half-transparent. This was always solved by pulling out the power cord from the underside of the monitor, then plugging back in again.

    Sometimes there was a little crackle from this method, perhaps i should've learn't that this isn't a good sign, but it was always fine.

    This time, however, this method resulted in 2 consecutive fairly audible pops, with noticeable flashes illuminating the wall behind my monitor.

    I've uploaded some photos for you to see, but they marks/damage looks identical to the thread posted below, even with the suspect ONE cap looking very slightly bulged (the only one).

    To me (a very untrained eye), it appears that a resistor along side that giant capacitor looking thing (which, of course, is the right terminology) has been damaged, as does the small brown cylindrical piece near where the lead plugs in.

    Im hoping it's a simple fix... probably not though eh

    I have access to a multimeter (and have done some research into how to use one prior to typing up this), and have a basic soldering kit which ive used a few times before with pretty neat results.

    Without further ado, heres the photos.

    Top of board (unlike in the other thread, i removed the metal plated covering the caps in the bottom right of the image to check them all). Only one seems bulging even slightly.




    Rear of board





    reverse view of small attached board (looks a bit damaged to me?)





    Shot of blown brown thing





    All capacitors apart from one looking ok?



    besides the far one?



    This resistor is knackered?



    General dirt/damage in area.








    I've tried to take the photos from similar directions so you can get your bearings.

    I hope this is enough information.
    Last edited by Megatonks; 07-31-2012, 05:27 PM. Reason: Added top image

    #2
    Re: Gateway LP2407 Power issue

    What you have done here is posted pictures in line which means that every time anyone opens the thread they have to wade through them all whether they want to see them or not. If you post any more (max resolution 2000x2000 and 2MB) use the manage attachments button, which is found by clicking "go advanced" under quick reply.

    I think the brown cylinder you refer to is a fuse. It is best to circle the items on pictures especially of you cant work out what they are. The board designations usually give a good clue - you can find out on wikipedia what most items are.

    Suggest you remove the BIG CAP -( carefully test it for voltage first it can hold 400v(then post another picture of the damage zone.
    Try and find other pictures of this board and identify the burnt components.
    Resistors - you need to find the colours of the rings.
    Clean of all the burn you can - try Isopropyl alcohol on a small brush or qtip
    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: Gateway LP2407 Power issue

      So, here is what I think happened. The switching mosfet shorted, blew the fuse and the resistor (probably a current sense resistor).

      It also appears there is more than a resistor damaged next to the cap, it looks like the little upright mounted daughterboard has some damage to it too (burned trace?).
      Muh-soggy-knee

      Comment


        #4
        Re: Gateway LP2407 Power issue

        That is the PFC Voltage booster circuits that blew up.
        Never stop learning
        Basic LCD TV and Monitor troubleshooting guides.
        http://www.badcaps.net/forum/showthr...956#post305956

        Voltage Regulator (LDO) testing:
        http://www.badcaps.net/forum/showthr...999#post300999

        Inverter testing using old CFL:
        http://www.badcaps.net/forum/showthr...er+testing+cfl

        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
        http://s807.photobucket.com/user/budm/library/

        TV Factory reset codes listing:
        http://www.badcaps.net/forum/showthread.php?t=24809

        Comment


          #5
          Re: Gateway LP2407 Power issue

          Sorry for image annoyance Selldoor. I guess i figured in order to have a clue what i'm on about then seeing the images was fairly necessary. Ill remember to do the advanced thing you mentioned next time.

          Thanks for the info guys. I'm going to do a bit more general research and try to figure it all out myself.

          budm, what's a PFC voltage booster? Which part is that on the board? i've googled it and can't see anything relevant?

          Does anyone know what the upright daughterboard is? It does look damaged to me and if it's cheap ill just replace it anyway.

          i'm going to refer to the other thread mentioned in my introduction to do the tests with the voltmeter and get ordering parts i think!

          Comment


            #6
            Re: Gateway LP2407 Power issue

            The PFC circuitson this board (picture #7) uses the inductor (next to the orange cap), the MOSFET and the Power Diode on the heatsink to the right, that board is may be for the PFC circuit.
            The Power Factor Correction circuits is used tO make the power supply to be more efficient (the voltage and current are in phase). When he monitor is of, the DC voltage on the primary DC filter cap will be about 325V (230 x 1.414), the monitor is on the PFC is activated, then the DC will be boosted up to about 400VDC.

            Last edited by budm; 08-01-2012, 04:13 PM.
            Never stop learning
            Basic LCD TV and Monitor troubleshooting guides.
            http://www.badcaps.net/forum/showthr...956#post305956

            Voltage Regulator (LDO) testing:
            http://www.badcaps.net/forum/showthr...999#post300999

            Inverter testing using old CFL:
            http://www.badcaps.net/forum/showthr...er+testing+cfl

            Tear down pictures : Hit the ">" Show Albums and stories" on the left side
            http://s807.photobucket.com/user/budm/library/

            TV Factory reset codes listing:
            http://www.badcaps.net/forum/showthread.php?t=24809

            Comment

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