I had three segments flashing on my 4 year old elite. Turned out to be the power brick playing up and I looked around and found this. I was initially a bit confused as I assumed all the power bricks would have the same wattage output....but that is clearly not the case. Equally from the feedback the plug attached can differ...why xbox, why?
Anyway, I checked my brick and found the output was 175W and ordered this power converter. The jack that is attached fit my elite perfectly. My XBOX is about 4 years old now, is the elite version and thanks to this converter is now working perfectly.
Make sure you don't throw your 3 pin plug away as you will need it, as this item does not come with one.
I'm really impressed...happy gaming everyone.