What was found
FLT 1672 - PIT-MDT - AFTER TAKEOFF FROM PIT, NOSE GEAR ALERT ILLUMINATED ON MFDU. THE BLUE INTRANSIT LIGHT REMAINED LIT IN GEAR HANDLE. CREW RECYCLED GEAR WITH SAME RESULT. CAPTAIN DECLARED AND EMERGENCY AND FLIGHT RETURNED TO PIT. FLIGHT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE CLEANED, LUBRICATED AND RIGGED THE NOSE GEAR DOWN LOCK PLUNGER MECHANISM. (M)