What was found
DURING CRUISE AT FL350 THE CABIN BEGAN AN UNCONTROLLED CLIMB. MANUAL CONTROL HAD NO EFFECT SO THE FLIGHT CREW INITIATED AN EMERGENCY DESCENT TO 10,000 FEET. IT IS NOTED THE CREW WAS ABLE TO REGAIN MANUAL CONTROL DURING THE DESCENT. FLIGHT DIVERTED TO DTW AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE PERFORMED BITE WHICH FAULTED THE NR 1 CONTROLLER. AFTER REPLACEMENT OF THE FAILED CONTROLLED BITE OF BOTH CONTROLLERS SHOWED NO FAULTS AND THE AIRCRAFT WAS RETURNED TO SERVICE.