Need advice from someone soldering lapto motherboard

Discussion in 'General Electronics Chat' started by jason9922, Dec 29, 2013.

  1. jason9922

    Thread Starter New Member

    Dec 29, 2013
    Well I'll just explain the situation. I scored a laptop from this girl that seemed to just need a screen. The model is a Toshiba L505D-GS6000. It seemed to be a perfect laptop to refurbish and flip since I got it for $30. Well I was wrong. The screen was the worst 16" CCFL which was $80, needed a keyboard $22, optical drive $14, ram upgrade to 4GB $40, battery & charger because both were junk $40. So currently I have almost $200 in parts into this POS. After everything I get it together and whenever I install Windows 7 the audio and USB ports don't work. After spending two days researching the problem I found out it's because of a motherboard problem.

    On the motherboard right below the trackpad there are two small pieces, I don't know if they are filters or what for the circuits but on my motherboard they are missing. In the picture I am showing they are both there still. The L4519 and the smaller one next to it are gone and I need to either just bridge the gap or take ones off donor boards (I have a bunch of laptop motherboards laying around from parts laptops I've bought). The larger of the two is about 1 1/2 mm big. I have no idea how to get one off another motherboard without just breaking it off. I don't have a soldering iron with a microscopic tip. Here is a quote from the Toshiba forum where I found out how to fix this extremely common problem with this L505D model:

    "What I usually find, is that L4519 has either broken loose or is completely missing. And the best reason I can figure, is that part of the touchpad components/plastics come into contact with L4519 and break it loose or knock it off the board. Of course it doesn't do it all by itself. It takes an outside downward force/pressure applied to the palmrest to cause this problem. I've repaired probably at least 60 of these motherboards and it's the problem every time"

    So after looking, yeah mine are gone. I added a picture they had posted in the Toshiba forum of a close up of what the L4519 looks like when it's still there along with the micro one next to it both as you can see have a broken lead. Again, mine are gone and I didn't find them inside the laptop. Can someone please help me or float me some advice on how to go about doing this because I don't want to ruin the motherboard and have to put more $ into this. Well I apologize, I can't find a way to add photos on here so a link to the page where they have the picture posted I wanted you to see is

    Many thanks in advance for any help. I have a soldering iron, solder, and no clean flux I use when I do a reflow. I took one of my soldering irons tips and filed it down so it's very sharp and small.
  2. trader007

    Active Member

    Feb 27, 2010
    use wick to clean the pads first, then use a pin to dab the pads with solder paste. stick the chip on there with tweezers, and melt with a fine tip solder iron.
  3. ian field

    Distinguished Member

    Oct 27, 2012
    In some cases the easiest way to shift a dud SMD chip is to shear the pins off close to the package, a Stanley knife is usually good enough - but blunt the point so you don't carve any tracks. Once you're left with just the pins, they can be swept up by the surface tension of a blob of fresh solder.

    The easiest way to salvage chips from a scrap board is with a modellers pencil blowtorch on the other side, if there's a few bits you want, heat a general area of solder and tap the edge of the board on the bench top. If you're after a specific chip, grip it with small pliers - twist very gently and you'll know as soon as the solder lets go.