What was found
UNABLE TO MAINTAIN CABIN PRESSURE AT FL350 WITH ENG ANTI-ICE ON. OUTFLOW VALVE INDICATED FULL CLOSED AND FLOW LIGHT ILLUMINATED. INCREASED POWER ON BOTH ENGS AND LOWERED AIRCRAFT ALTITUDE BUT CABIN ALTITUDE CONTINUED TO CLIMB. WHEN CABIN ALT REACHED 10600 FT CREW DIVERTED TO AMA. FERRIED A/C TO DFW. FOUND LEFT ACM SEIZED. REPLACED ACM. PRESSURIZED AIRCRAFT, ALL OPERATION CHECKS GOOD. CHECKED RIGHT PACK, OPERATION GOOD.