Reasons why this happens:
When Microsoft designed the 360, they chose a slightly unusual way of mounting the heat sinks to the processors. When the console is running, there is a tremendous amount of heat build up inside the case. This causes the motherboard to flex against the X-Clamp support plastic (see picture 1) which in turn can cause the soldered joints on the processors to come away from the motherboard itself. This results in the Red Lights of Death. Due to the inefficient design of the heat sink clamping method, this is a very large problem. Although Microsoft haven’t (as of yet) come up with a decent design fix. On the latest ‘Elite’ versions of the console they have used epoxy resin to ‘glue’ the corners of the processors down to stop the flexing that causes this error (see picture 2). Whether their fix will stand the test of time remains to be seen. What the modification contained in this manual achieves is to alleviate board flexing and apply uniform pressure to the processors. This uniform pressure is enough to ‘remake’ the faulty joints resulting in a working console. Also, because the pressure on the processors is uniform the heat sinks do a much better job of dissipating the heat build up.
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An extra Wii Remote allows for multiplayer fun.