
My old soldering work was still looking good after a year of playing so i started to look at the traces.. Then i discovered it, a very little bit of a thiny trace had burned(?) of. Looking at the surrounding traces it looks as though there have been some problem with the manufacturing. Several of the traces in the neighbouring area are damaged, looks like the board has been dirty during the production so the traces has been eched a bit to much. (look at picture 1 - closeup. Circle nr.1 shows the trace that was completely broken, Circle nr.2 show a trace that is just half the width it should be)
what i did was to peel of a little bit of the isolation covering the trace nearby the gap and soldered a very thin copper wire across. Due to a flat battery i have no picture of the outcome of this surgery, and who is waiting for the batteries to recharge when the xbox might be working again? not me!
And guess what, when i inserted the power cord it stayed off! And it worked 100% when i used the power button too. So i guess i found the problem, lets just hope the other traces will last a few more years before breaking down..
Picture 1: (closeup of the spot with broken trace(circle 1) and "half-bad" trace (circle 2))

Picture 2: (overview of the card with the closeup marked with red square)
Xbox is version 1.1 by the way.