I'll tell you what I know. I've fixed about 6 of these RROD.
The error is generally caused by the X-clamps pulling so hard at the motherboard that they bend it away so that the pins of the GPU don't touch the solder on the motherboard any longer.
This isn't comprehensive but it's an overview.
Required item:
Thermal Grease
x1 - Wagner HT1000 heat gun
x8 - Machine Pan Screws - 5mm x 10mm - Home Depot UPC 030699 801282
x8 - Washers - Steel 5mm - UPC 030699 363087
x16 - Washers - Nylon #10 - UPC 030699 869381
1) Disassemble XBOX 360.
2) Remove the Xclamps and throw away.
- YouTube for the easiest method.
3) Use GooGone or rubbing alcohol with Q-tip to clean old thermal grease from the heat sinks and CPU + GPU.
- Make sure you leave the CPU / GPU with a completely new mirror finish.
4) Cut hole out of a sheet of foil big enough so you can see the CPU and GPU through it and lay it on top of bottom of motherboard.
5) Turn on heat gun to high, run it back and forth in rows over motherboard in rows, then do so in the other orientation (first vertically, then horizontally), then make small circles around the CPU about 5 times, then the GPU. Then start the process over. Do this for 3 minutes.
- Let it sit for an hour. Don't even remove the foil. Moving anything might warp the board.
6) Repeat steps 4 and 5 on the top of the motherboard.
7) Put thermal grease on each processor and spread it into a thin layer using something like a credit card.
8) Put heatsinks back on using the screws and washers in this order: screw > n. washer > motherboard > n. washer > s. washer > heat sink
- Screw it in until it gives resistance, but don't tighten.
9) Turn XBOX 360 on (don't plug fan in) and let sit until you see only two red lights blinking, then let it sit for 45 seconds and turn it off.
- Let sit for 30 minutes.
10) Reassemble XBOX 360 and enjoy!
Take note some people recommend not using this method as it may cause damage to the motherboard. I personally have fixed several this way, and there are plenty of other people online that have as well. I've never heard of someone actually damaging their XBOX this way, although I'm sure there are some.
People will also say that this isn't a good fix because it's basically a poor man's reflow/reballing. Which I guess is true considering proper reflow stations can cost over $1,000.