Long-time lurker here, hoping someone can help me!

My Potinara Hoku Gem 'Sunspots', which I've had for about 3 years, has
recently developed some red spots on it, as well as some brown "bubbly"
blisters. I thought the blisters might be scale, but couldn't just rub
it off, so I scratched one of the blisters, which of course left an
open wound on the plant. There is one leaf which is worse than the
others, and it is completely closed up.

here are some links to pics of the plant:
http://i23.photobucket.com/albums/b3...otsredarea.jpg
http://i23.photobucket.com/albums/b3...spotsbumps.jpg
http://i23.photobucket.com/albums/b3...potsbumps3.jpg
http://i23.photobucket.com/albums/b3...potsbumps2.jpg
http://i23.photobucket.com/albums/b3...GSunspots2.jpg
http://i23.photobucket.com/albums/b3...GSunspots1.jpg

Could the red spots be sun burn? I grow in a south facing window and
have always had the plant in the same spot. None of my other orchids
near it (BLCs) have any problems (yet). I have quaranteened the problem
plant.

What about the brown bubbly blister spots? another form of scale or
another pest, or maybe disease? SHould I just cut off the problem
leaves and dust with cinnamon? Is this something I should worry might
spread to my phrags, brassias, and others, or might they be safe
because they have a different type of leaf?

Any advice is appreciated.

Thanks,
Mary