Phal won't grow new leaves

[Aubs86]

Hi everyone!
I live in the northeast and have been growing orchids for about 6 years. I have them in a west window without any direct sun hitting them. I have Noid phals and a few oncidiums and a Maxilaria Tenufolia. 9 in total. So far they are all thriving except for one. It happens to be the first one that I bought.
It's a phal that I have had for about 6 years. Since I bought it it has never grown a new leaf. Once a year it puts out a short spike but only gives me one flower. The color of the leaves indicate to me that it gets good light, it has a good root system, no rotting roots. I fertilize every other watering. Any ideas what could be the problem with him?
Thanks sooooo much!