What was found
WHEN ENG ANTI-ICE WAS TURNED ON, THE BLEEDS TRIPPED OFF & CABIN PRESS STARTED TO CLIMB. EMER WAS DECLARED & A DESCENT WAS STARTED. RESET PACK TRIP, PRESSURIZATION RETURNED TO NORMAL. FLIGHT DECLARED AN EMER, DIVERTED & LANDED WITHOUT FURTHER INCIDENT. ACFT WAS REMOVED FROM SERVICE. INSPECTED & RAN BOTH ENGS AT IDLE WITH ALL BLEEDS ON. GND CHECKED ANTI-ICE, BLEED & PRESSURIZATION SYSTEMS. NO PROBLEMS FOUND.