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Posts Tagged ‘keyboard’
As a laptop technician, a fairly common problem I see today is a large number of failing HP laptops, particularly of the DV 2000, 4000, 6000, and more recently, the 9000 series laptops. These particular models are fairly notorious in the laptop world for simply just refusing to work all of a sudden. They will turn on, appear to get power, but there will be no display and the laptop will not present any additional signs of life.
What is happening here? The built-in video chipset is failing. It is built into the laptop’s motherboard, and while the rest of the board is working fine (which is why you can turn the machine on and see all the indication lights), since the video chipset is built into the motherboard, the computer ultimately will not work.
Why does this happen? Well, this goes back to around 3-4 years ago when nVidia, a major video chipset maker, switched from a lead based solder that had a high melting point to a tin based solder that has a much lower melting point. This combined with a fairly inadequate cooling solution from HP/Compaq leads to a video chip that runs very hot, right on the edge of its melting point hot. Over a period of time, as the computer is turned on and off over and over again, the soldering joints that hold the video chip into the motherboard start to crack and micro-fracture. Obviously when this happen all kinds of malfunctions will occur and you see the problem that is happening today.
This affects a wide range of laptops since nVidia makes chipsets for nearly all the major companies, but HP and Compaq were affected the most because they seemed to not only have output more of the nVidia based laptops than the other companies, but they also went cheap with the cooling solutions for their video chips. It was only a matter of time since they started dropping like flies, and indeed, they did so much that HP was forced to initiate a recall (since expired).
What do you do when this happens? Well, before you splurge and buy a replacement motherboard, a new laptop, or drop some good money to get a guy like me to fix it for you, there is a solution. Even if you are not computer or mechanically inclined, it’s a nice project to try because it’s not like you can screw the computer up any more than it already is anyways.
The fix is called a reflow. Essentially, what we do is isolate the video chipset on the motherboard, and apply a very high degree of heat directly to it. Enough heat to melt the solder built into the chip. This will allow the micro-fractures in the solder to melt back into themselves, allowing them to complete their circuitry again. It’s kind of like a reset at the hardware level.
At my job, I see about 1-3 of these machines come in per week, and most commonly they are the DV series, so when a DV 2000 came in today, I took the opportunity to take some pictures and write a how-to. It’s worth noting that while all models of the DV series are quite similar to each other, keep in mind that every laptop will have its differences. No two laptops of different models are completely alike, but the fundamentals for taking them apart are largely the same.
The first thing you will need to do is to acquire the appropriate tools for the job. Allow me to plug in my employer Geek on Wheels Computer Repair in Denton Texas for supplying me with the majority of these tools as well as the bench-space to do this with (along with the customer’s computer!):
Heat gun (Nothing fancy is needed, I’m using a cheap $30 Wagner 2 stage heat gun)
Soldering Iron and Solder (alternatively, an IR thermometer, but I prefer this method for reasons you will see later)
Heavy Duty aluminum foil
Copper shim and thermal paste (not needed with this computer it turns out, but with other models or older versions of the DV 2000 it’s very useful)
Small needle nose pliers (not pictured, rarely used but handy if there are cables that are too small and delicate for someone with fat fingers like myself)
Once you get your tools, it’s time to get to work with your computer. Here’s our patient right here:
I’m using my Google G1 to take these pictures, so they may not be of the best quality, but what I’m trying to capture here is this model’s problems. You can see in the second picture that the computer is turned on, however there is no video.
I should say that before you undertake this job, RULE OUT ALL OTHER POSSIBILITIES FIRST. You do not want to reflow the video chip only to find out that you had bad RAM the whole time!
Anyways, let’s get started. First thing we do is unplug the machine, then flip it over and remove the battery.
Set the battery aside. After this is done, start removing all the panels from the bottom of the laptop.
Here you can see the panels that reveal the hard drive, RAM, and the wireless NIC. Remove all of these components, and set them and their screws aside.
After this, remove the DVD/RW drive. For some reason I put the screwdriver in the wrong hole, I’ve circled the screw that holds the DVD/RW drive in place. Most manufacturers of laptops will make it where you can remove the drive by removing a single screw from the bottom of the laptop and then you just need to pry the drive out.
After this, proceed to remove every screw you can find from the bottom of the laptop. Whenever you cannot find any more screws to remove, flip the laptop over and then open it up where the LCD is upright. The next step is to remove the sensor bar; it is going to be located above the keyboard.
I’ve pried it up just a tad so you can see it. This is where the flathead will come in handy. Gently yet firmly wedge the flathead between whatever crevice you can find between the laptop’s shell and the sensor bar and wedge it up. It’s going to be held on to by plastic latches and sometimes screws, but since we removed the screws we simply need to unhinge it from its plastic latches. Don’t force it, take your time.
On many laptop models the keyboard does not come up with the sensor bar and the keyboard is held into place with a series of screws just above it. This keyboard is not like that, as the sensor bar comes off it will lift up the keyboard as well. They keyboard itself is held into place by screws on the bottom of the laptop, which we have since removed. At this point the sensor bar is off its hinges but it will still be hanging on by two cables, but before we remove it completely we will take the keyboard off first.
Here you see the keyboard is attached to the motherboard through a thin ribbon cable. This cable is held down by a plastic latch. You loosen this latch by gently pushing up on both sides, then removing the cable. Do not over-do it on the pressure in loosening up the latches, they are easy to break.
Once you remove the keyboard, you need to remove the cables that are holding down the sensor bar. Here’s a small ribbon cable and a latch that are like a miniature version of what the keyboard had. Remove this by once again pushing the latch up gently on both sides.
Here is the other cable that connects the power button on the sensor bar. There’s no latch here, just pull the cable out, firmly but gently. Use the needle nose pliers if you have to, as there’s not too much room for fingers.
Here’s the laptop now without the sensor bar or the keyboard. Our next goal is going to be removing the LCD screen. First we need to remove all the cables that are attached to the screen before we go to the screen itself.
Here I’ve pulled out all of the cables. Most laptops will have the WIFI antenna that runs from the wireless NIC to the LCD itself. You just pull it out of the hole. The other cables on the right are the right side antenna and another cable for the webcam. Now we move onto removing the screws that hold the LCD in place.
Removing the screws for the left hand side.
Right hand screws are a little trickier to find, but you’ll see them.
After the screws are removed, the LCD will simply lift off. Set this aside in a nice safe spot, away from all your screws and other components.
Here’s computer without its LCD. Now we can focus on removing the upper and lower parts of the shell to get to the motherboard. First remove the screws you can see on the top part. Once these are removed you can start separating it from the bottom.
Here I’m pulling it apart. Once again, be firm yet gentle. The shell is holding onto itself with plastic latches at this point. You can break their grip by using your flathead screwdriver or prying them out with your hands. Do not force anything. If the computer refuses to come apart at a certain point, DON’T FORCE IT. Check to see if there is a screw you missed that is holding it down, or approach it from a different angle.
Once the top part is loose, it will cleanly lift. You’ll notice that there is one last thing holding it down, and it’s another ribbon cable, this time the one that connects the track pad to the motherboard. Remove the cable and you can finally extract the top part of the shell. Put it aside.
Here now we can see our first full glimpse of the motherboard. Before you can remove the board from the bottom shell, we need to remove a few cables and screws.
Here on the top right part, we see the connectors for the power and right hand USB ports, which are on their own separate circuit board. Go ahead and remove these cables. Be careful of the power cable; it’s held down pretty tightly but its plastic is flimsy. The cable on the top is actually connected to the speakers which are located on the top left as well as the top right.
Top left. Here we can see the left speaker.
Bottom left. Here we see the cable which connects to the WIFI switch.
First thing we do is remove this WIFI switch, then carefully detach its cable. Set it aside.
Second thing is to remove the left hand speaker. The right speaker is a part of the bottom shell itself and doesn’t need to be removed, but we cannot extract the motherboard without first removing this left hand speaker. Once it’s removed, carefully unplug it from the motherboard, and set aside. You can let it hang off the bottom shell if you want, just make sure it doesn’t snag on something.
It’s glued down, so carefully remove it with your flathead.
After you’ve removed these items, there’s one last thing to remove before you remove the motherboard. This part tends to trick everyone, but HP has this expansion port that I’ve never ever seen anyone use. Notice to two screws. These things have to be removed with your flathead screwdriver before you can finally get the motherboard out.
At last, the motherboard is ready to be lifted from the computer! We want to lift it up and away from its connections on the shell. Grab it firmly yet gently on the right side, lift it up, and then away.
Just like this. Take your time.
On this motherboard we have this IO guard. It will be loose, just take it off and set it aside.
The motherboard in all its glory. Now we are going to remove the heat sink/fan from the processor. This same heat sink/fan also cools the video chipset. The video chip and the processor sharing the same heat sink? Gee, I wonder what could go wrong….
Remove the screws in a diagonal pattern. Top left, bottom right, top right, bottom left. Then the screw on the side.
Underneath the fan, you’ll see its connector. Remove this, and you can remove the whole thing.
Pulling the assembly off. On the right is your processor. On the left is the video chip. This is what we are going to reflow. Notice rubbery thing on top of the video chip. This is the thermal pad, and you don’t want to lose it. You will want to put it back when you are done, and it is very easy to mess up, so be careful when you remove it. Use your flathead.
Here it is without its thermal pad. This chip right here is what we are after, and what is responsible for the problems the computer is having. Now we are going to focus on isolating this chip with foil, so we can prevent the extreme heat from our heat gun from affecting the other components of the motherboard.
This is accomplished by using heavy duty aluminum foil. Here I’ve taken off a piece of foil big enough where I can fold it 3 times, I cut it off so it fits over the motherboard, then I apply it right over the top of the board, folding in the edges so it stays in place. Notice where the video chip Is, I’ve pressed down on it enough that you can actually see the chip.
Now, we take our razor, and we CAREFULLY cut around the video chip.
After cutting out the layers, I take a single layer of the foil I cut out and apply it to the chip itself. I then smooth it down very tightly, like how you see here. This will distribute the heat more evenly around the chip itself.
Now here’s a little trick I do to tell when I’ve reached the right temperature, this was told to me by a fellow laptop tech. You get your soldering iron and your solder, and then melt off a nice blob of it right on top of the chip itself. This acts as your temperature gauge. Whenever the solder starts melting, you know you are at the right temperature.
Now take your heat gun, set it to its low setting, and gradually begin building up heat. Start somewhat at this height and then move it closer and closer, until it’s almost right over the chip. Then switch to your highest setting. The whole time you should be moving the heat gun in gentle circular motions. Focus all the heat only on the chip itself.
This is how close you need to get once you start letting er rip at the highest setting. Remember, nice circular motions, gradual heat build up until you are at the maximum level. I take roughly about 60 seconds to get to the highest level, and at this point it takes about another 20 until I can see the solder melting. Once I start seeing the solder melt, I count to 5, then I set the gun to a lower setting for another 15 seconds, then I turn the gun off, set it aside, and then go do something for another 30 minutes. The internal solder has probably been melted down to this point, we want to give it plenty of time to cool and reset itself.
Now we can test it! Before we put the machine back together, it’s good to see if what we did actually worked. With this model we can do this fairly easily. Get your RAM, battery, heat sink/fan, sensor bar, and LCD. Attach the heat sink/fan first. Make sure you connect the cable that powers the fan. Then take a stick of ram, and put it into its slot. Then, hook the LCD to its connector, and the power button and ribbon cable from the sensor bar to their appropriate spots. Then carefully slide the battery to its connectors on the underside of the motherboard.
Push the power button. Cross your fingers.
When you see the splash screen you’re back in business.
From this point you put the computer back together, essentially following the steps I outlined above in reverse order. Remember to be careful, and don’t forget to put the cables back to where they were in the first place! It would suck to put the computer all the way back together and then realize that you forgot to connect the speakers! (Speaking from experience here)
Here’s the same computer, with a new lease on life.