Cambria and oncidium problem
 

Both former healthy orchid is my collection since months.
Oncidium leafs became slowly yellow, it reminds me a similar problem,
which led to a dead dendrobium, months ago. The cambria became spotted
with brown irregular spots in 2 days.
I have phals with these orchids, all of them are in flowers since
months, healthy, strong plants without any problem. I spray them in
every 1-2 weeks with Dithane, I keep them in good temperature and
humidity. The light is less than normal in these weeks because of
strong winter times but everything else is normal.
I'm afraid, I'll loose both plants. Would you check the pictures and
suggest a cure for poor orchids? I separated them already.
http://www.whitewater.hu/Mc/phalaenopsis_x.html