What was found
AIRCRAFT WAS GROUNDED: DURING A SCHEDULED SLIDE CHANGE FOR THE L1 DOOR MAINTENANCE REPORTED WITH THE REPLACEMENT SLIDE INSTALLED, WHEN THE L1 DOOR WAS PLACED IN THE ARMED POSITION THE FLIGHT ATTENDANTS PANEL DID NOT INDICATE GREEN AND ARMED. MAINTENANCE FOUND THE REPLACEMENT SLIDE WAS CAUSING THE ISSUE AND REPLACED THE SLIDE WITH A SERVICEBLE UNIT. THE REMOVED SLIDE ASSEMBLY WAS CLASSIFIED AS BAD FROM STOCK AND WAS ROUTED TO BE SENT OUT FOR REPAIR.