Fix it Yourself
So, you want to play your favorite game for your Xbox 360? You hit the power button on either your controller or the face of your system. Instead of the green light encircling the xbox logo and then resting on the set amount of lights that correspond to how many active controllers you have, you get 3 flashing red lights.... No matter what you do this keeps happening. So what now? Ok all hope is not lost, lets get started.
If your system is still under some type of warranty begin by trying to either get your money back from your local Wal-mart or wherever you got the thing or it's possible that you can ship the system into Xbox it'self and they will refurbish your system and send it back to you. If you do this first find out if you have to leave the hard drive intact or not I would suppose that you do not since there is nothing wrong with the hard drive this is not the issue. But if still under warranty this would be best option since there is no guarantee that you can fix this thing, although it's quite likely that you should be able to if you have a little bit of patience and common sense.
Ok so your system is not under warranty and you want a quick fix to get back to kicking it online with your friends on Gears of War 3 or something. First try this. Make sure system is completely off, remove all memory cards whether it be small front loading cards up to the harddrive it self. These things should simply pop out with little effort. Also if ya got the wi-fi adapter probably good idea to pop that off too unplug controllers all that. Make sure it's plugged in and push the button to turn it on. So it's still flashing right? No problem. While the system is on and the red rings are flashing, take anything you can find that you can wrap around this system to heat it up. Most people just use an ordinary towel seems to do the trick. you could use a throw blanket or whatever but a bed sheet is too thin and probably not gonna do it. basically your trying to completely cover the thing up let no air in or out so it heats up pretty fast. Let it sit wrapped up and ON for about 20 mins or so and try not to walk away and forget it as it could probably melt, or maybe even start a fire i'd imagine after good while. (like overnight). Ok once it's been around 20 mins to half an hour reach inside and feel the top the system should be pretty warm, not burn your hand with welts warm, just hotter than usual. Turn off the system, remove the towel, give it another 15-20 mins or so and let it cool a little. Then plug bag up your hard drive, controllers and stuff like that. Press the on button again and 9 times outta 10 times it will work like a charm. (at least for a few days)
Taking it apart
There are many Youtube videos on this and with a little research you will find detailed steps on how to do this but obviously you start by unplugging the system from the wall, this is VERY important.
Take away all connections, power cord, tv cables, controllers, hard drive.
The cover is the hardest part by far in taking this thing apart if you've never done it before. Although fairly simple if you've figured the thing out like I have. Start by pulling the faceplate of the front of the Xbox. These come off easily and you can even buy cool artwork covered faceplates at game stores and stuff (they are supposed to come off).
Now you should see some little tabs under there where the faceplate is. These are your keys to getting inside the easy way. First take off the eject button it's usually silver or white and you'll be able to see how simple it is to pop off, this is important so pop it off now, should be no problem.
Now loosen the white tabs on the front of the xbox under the faceplate. Should be about three or four. The Xbox should now partially open on one side like pac-man's mouth. The easy way and best way to open this is by setting the xbox down on a table or something. One flap is open and loose, the other flap is connected to the insides of the Xbox. Sit it where the top loose part is on top and basically press down on the bottom silver half and rip the mouth open very rapidly... the top part of the case will just pop right off and will not break anything. Look up " quick way to open xbox case" on Youtube you'll see exactly what I am talking about. From there you will be removing the following screws from the pic below.
You will need a Torx screwdriver set to do this. They are around 10-15 dollars at hardware stores or computer stores. They are quite common and useful and I found mine around the house kinda by accident but they are not very expensive. You also need Thermal Paste or Thermal Compound. I have paid about 7 dollars for this don't pay 20 or 30 dollars for this it should be fairly cheap at say a RadioShack or some place similar.
Remember to take it apart with patience and keep each different size screw seperated and note where they go, there are only 3 different types of screws and you will notice a marking system of where these go depending on the length. Notice the M and then there are some little arrows. The longest screws have no marking in the slots where they go and well that is kind of theyre marker ya get it? Refer to Youtube videos for help. I am here to tell you that I have done this several times and it is very possible. In fact I have only been unsuccessful one time in repairing these things at least for a few months at a time.
Basically your trying to get to the two chips that have the gray goo on them called thermal paste that has worn out. Use rubbing alcohol to clean it out and generally spray out all the dust inside your xbox and wipe dirty spots or dust buildup spots with alcohol as well. It will not hurt the electronic components inside. Once clean of grey goo replace it with a thin layer of the new thermal compound. I do this by squirting a small line down one side of the chip and using something like a credit card or ID to smear a nice coat across the top. I'd say that a little too much is better than too little, but try to make it thin and evenly applied.
Check for the 4 rubber pads that are on the other 4 important chips. I recommend discarding these and replacing them with something better. I use two penny's for each peice of rubber i'm replacing. Stack the two pennies on top of eachother and wrap a thin layer of electrical tape around them as tight as possible so that no copper is exposed. Use a little dab of the thermal place to secure them back to their locations where the rubber or foam squares used to be and carefully place the motherboard back into it's original position. Check YouTube for a better description of this but if you are looking inside you will clearly see what I'm talking about.
Now that everything is secure begin putting the Xbox back together in the exact reverse process you took it apart. Once the motherboard is tightly secured along with the X-clamps , the Fan cover and Dvd drive is reconnected. The power button and board is popped back into place. plug it up and try it before you even completely put the cover back on. Temporarily pop your eject button back into place so you can open the try and pop in a game. Do not touch the insides of the Xbox with the cover off. Although you can play and run your system with the cover off it is not Safe to put your hands near anything other than the eject button and the controller ports stuff like that ok. But I do this to save time just in case something did not go smoothly in the Thermal paste department or maybe I forgot to reconnect my dvd drive properly. Best to realize this before i've put the entire thing back together only to figure out i got to start all over. Just a tip since i've been through this many times.
If this doesn't work.
It is also possible that stripping the entire thing down to just the mother board. Removing the penny's/rubber pads, cleaning the goo off and then heating up the mother board with a heat gun, can help re-sink the GPU and CPU. This has also worked for me. But be careful not to overheat it and warp the board or burn yourself. Just run the heat gun which is about 700 degrees about 2 or three inches from the board in a quick circular motion until you can feel the heat coming off the board. Should take about 3-4 minutes each side. When this doesn't work for me i'll repeat the process getting a little hotter each time since if this doesn't work then i'll probably not going to be able to repair this thing anyways. One time I almost swore it was about to melt but it didn't and it ended up working so I think you can get it pretty hot. When I say working I mean put it back together and give it a try. Each time removing and re-applying paste and pennies. Focus the heat on the parts where the goo is and the rubber goes these chips are what need to be reset. Just do not leave the gun sitting in one area too long constantly move it around the board so you don't burn a whole through it. Now replace the Thermal paste, your pennies all your screws and parts and try it again. Again check youtube for this information as well will guide like I said just want to give you some encouragement to try this yourself as it can actually be kinda fun as well as a much quicker way to getting back to your beloved games!