Voodoo3 3500 only have tv out, not tv in, and for the other question about the voodoo2, it isn't a graphic card at all, it was an 3d enhancer wich need a graphic card in a pc, only used it when needed, so you need a graphic card in order to use it. The other factor is that the driver of the mediator as said in the thread doesn't support voodoo2.
By the way, agp to pci adaptor???, is this possible?
