Maxillaria tenuifolia Not Blooming

[JohnVP]

I purchased a Maxillaria tenuifolia 3 years ago. At the time it had a few flowers, however it has not bloomed since. I water it every 3 or 4 days, and it is in the shade, in a brightly lit window. I am located at 6800 feet above sea level in central Mexico. The plant was transplanted into a pot using a commercial orchid mix of wood chips, pebbles, and charcoal pieces. The plant appears healthy but has browning at the tips of some of the leaves, which was not the case at the time of purchase. Otherwise the orchid seems quite healthy.

Can anyone give me some advice as to why my orchid is not blooming.