What was found
(CAN) DURING PRE-FLIGHT CHECK, FLIGHT CREW REPORTED AN INDICATION PROBLEM WITH THE RIGHT ENGINE FUEL EMERGENCY SHUT-OFF VALVE. DURING TROUBLESHOOTING, DIODE 2822-CR3 LOCATED AFT OF THE RIGHT WING REAR SPAR WAS FOUND BURNT. OVERHEAT DAMAGE WAS ALSO NOTICED ON DIODE 2822-CR4 AND ADJACENT WIRES, SEE ATTACHED PICTURES. DIODES WERE REPLACED, ELECTRICAL WIRES REPAIRED AND SYSTEM TESTED SERVICEABLE BEFORE RETURNING THE AIRCRAFT TO SERVICE.