Your's is a 0.1 mf bypass capacitor--not too hard to find. Just make sure that the voltage rating is adequate. A more typical failure mode for these is a short, accompanied by a blown fuse. You've already done the hard part--opening the power supply. ;-) Good luck! -michael Check out amazing quality sound for 8-bit Apples on my Home page: http://members.aol.com/MJMahon/
There's more to it, it seems. There's some melting of the plastic on the very large ?transformer 3/4 to the left, and probably obscured in those photos by the edge of the picture.
I am already looking into sourcing a replacement power supply. It's too soon for my IIe to bite the dust I think.