Need help with encyclia cochleata losing leaves

[BillieG]

I bought an encyclia cochleata from Hausermann's a month ago. It was in a small amount of dark medium in a small pot, so I repotted it in S/H. It had 4 leaves and a very small spike

Today I noticed the leaves were yellow and some brownish. When I picked it up to carry it to the kitchen 3 leaves fell off with only 1 yellowing leaf remaining. It has been sitting 2 feet back from a south window, and I have watered it every 5 to 7 days. I have not given it any fertilizer.

I have an encyclia alba that is very happy and blooming in these same conditions, so I don't know what I'm doing wrong.

I believe it is going to lose the last leaf as it is yellowing. Does that mean it is will die? I looked at the roots today and they look fine.