Oncidium ampliatum brown areas

[lithopgirl]

I'm new to OrchidBoard, but have been growing orchids for more than a decade--mostly phals and paphs. Recently, I've expanded my collection to include many other genus. Last month, I picked up an Oncidium ampliatum (Turtle Shell Orchid) at a seller in Texas. When I got it home, I realized it had snail damage (chewed roots) and large brown areas on the bottom of most pseudobulbs (I assume it was planted too low in the pot). I use Agdia ImmunoStrips on all my new orchids, and it tested negative for major viruses. The brown spots are not soft--they feel turgid like the rest of the pseudobulb. What are the brown spots, how do I treat it, or is this guy a lost cause? Thanks.