The First PHotoelectric Astrolabe (PHA I) of China was installed at Shaanxi Obs. in 1971 and came into use later. PHA I has been operating automatically since 1986. Now it is being revised by using a single image with autocollimation, equipped with photon counting system and a tracking diaphragm with a small window to follow the star in zenith direction, which would cut off the most light of the night sky. With all these three approaches, PHA I could improve its limiting magnitude from mag. 6 to mag. 11 or even fainter.