This was taken from the pinned topic for this section:
0102 Error in the "Digital Backbone" (CPU/GPU/RAM), this is usually caused by a cold solder joint between the GPU and the mainboard.
There are two theories to fixing this one deals with the "X" clamps that hold down the chips. The other involves re-Heating the chips. DO NOT attempt either of these if your console is still under warranty. If your console is still under warranty return it to the store where it was purchased or call MS to have it replaced.
I haven't heard any instances of this error being related to a J-Tagged Xbox 360. I would suggest taking it apart and fixing this yourself, even though you aren't keen on it.
I x clamp fixed a 0102 error xbox and it didnt work. If that does not work look up the eraser fix. It worked for me. Basically you put squares of an eraser on the ram chips to apply pressure.
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