What was found
CABIN PRESSURIZATION CONTROL SPIKED OR BUMPED AT FL 350, CABIN WAS CLIMBING AT OVER 4000 FPM. THE CABIN ALT WAS AT 8000 FT. DECLARED EMERGENCY AND DESCENDED TO 10,000 FT. CHECKLIST WAS PERFORMED. TROUBLESHOT THE PRESSURIZATION SYSTEM IAW MM 34-11-00, AND 21-32-00. REMOVED AND REPLACED THE NR 2 ADC IAW MM 34-11-30, LEAK AND OPS CHECKED GOOD. ACCOMPLISHED PRESSURIZATION CHECKS WITH THE ENGINE RUNNING, SIMULATED FLIGHT, OPS CHECKED GOOD IAW MM 21-32-00. PERFORMED A NR 2 ADC TRANSPONDER INTERGRATION CHECKS IAW MM 34-54-05, OPS CHECKED GOOD.