I have fixed a whole lot of OG Xboxes, but I have finally run into one that has me stumped. The unit didn't turn on at all when I got it and had never been worked on. After I opened it up I saw the usual 5 3300uF caps were pretty bad, so I promptly replaced them, but the unit still doesn't power on at all. I checked the PSU, tests OK and I tried a known good one just in case, still no difference. Tried a spare front button board as well, still no difference. I plugged in a good 1.6 board to check a few random components that get voltage while the console is off. The dead board got no voltage whatsoever on the same components, so I think it is some sort of a power issue. Any suggestions?