Sick Oncidium Peacock?

[Fran20]

Not sure what's happened to this plant. It bloomed in Sept. In mid-Nov. it was growing a new lead and looked healthy. (Photo1) At the end of Jan. pseudobulb started to shrivel even with regular watering schedule. Past week, leaves turned yellow. (photo2). Unpotted today and yellowed leaves fell off. I removed predominantly sphagnum moss plug and surrounding media made of sphag and bark. No pests observed. Please tell me what you see as far as condition of roots or any signs of disease. I was thinking of repotting in slotted plastic 4"pot with lava rock. What should I do now? Your advice is very much needed and always appreciated!