iBook G3 16VRAM dual USB problem: power-on got brief "whirr" but no chime, no vid, no disk spin, tried resetting PMU. Replaced logic board, restarted and reset PRAM 3x chimes. HD spins OK, but no vid. Then I began to smell that "burnt" smell as if there a power supply problem -- yanked AC. Before I go buy a DC board thinking it's a power supply issue, then find out it isn't and fry another logic board [which I may have done already], any suggestions here?