What was found
CREW REPORTED THEY WERE UNABLE TO EXTINGUISH NR 2 HYDRAULIC LIGHT ON STANDBY GAUGE. RAN CHECKLIST. NO GUIDANCE IN CHECKLIST FOR IF LIGHT DOES NOT EXTINGUISH. USED SYSTEMS DIAGRAM AND KNOWLEDGE TO ASSESS THE SITUATION. MAINTENANCE CONTROL ADVISED TO RETURN TO DEPARTURE. AN EMERGENCY WAS DECLARED AND LANDED WITHOUT INCIDENT. REMOVED AND REPLACED THE NR 2 SYSTEM PRESSURE TRANSMITTER 9D2 IAW FMM 29-30-2 & 29-10-2. OPS AND LEAK CHECK GOOD OF STANDBY HYDRAULICS, AND NR 2 HYDRAULIC SYSTEM DURING ENGINE RUN-UP IAW MM. AIRCRAFT RETURNED TO SERVICE.