Dendro yellowing

[Koiscale451]

I bought my one dendrobidium and it was in potting soil (yes I know, bad) and I repotted it in orchid mix on sunday. It was in the potting mix for at least two weeks and I didn't keep it too wet. A few days before I repotted it it started yellowing on the leaves in small pale areas and now two of its bottom leaves fell off and more on the way! Its roots weren't rotted and it looked fine before. Is it going to rest for the 'winter' or is it dying?

[Chubidubi]

Dendrobiums tend to loose old leaves and some canes even go leafless. It's normal for them. To be sure try posting a pic of it so we can have a look at it.

[Koiscale451]

Here's a pic:

Even the new young leaf is yellowing!

[Chubidubi]

Looks like it's been over watered and the soil it was in didn't help either. How are the roots looking now?

[Koiscale451]

Roots are a mixed variety of normal and partially rotted, cut most of the rotted. What should I do?