Phal in a rut ?
 

I had 3 phals that were doing nothing - no new leaf growth, no visible root growth. The potting mix looked fine and there were no visible problems. I had even tried moving them into different light intensities.
I then had ( it turns out ) a eureka moment and decided to repot all 3. Strangely enough the roots when I checked were ok and I didn't have to trim any on the repot.

Its been about 3 weeks and all of them have a new leaf and also root growth from the "stem". Its like they literally have a new lease on life.
The moral of this story is that a repot into fresh media may be just the thing for lacklustre orchids with no visible problems !

Yes, I completely agree (good to repot during the right time of year, too) I've had the exact same thing happen to a few Phals this summer.

I completely agree. I have a Psychopsis that I decided to repot since it was just not doing anything, and after about two week it had two fat buds, and a new growth.

I've had a Miltoniopsis stall and crash because I didn't change out the potting media. So, yeah, repotting is a routine, not an option.