What was found
DURING ANNUAL INSPECTION, ELT WAS FUNCTION TESTED. SWITCHING UNIT TO ON, IT WOULD OPERATE FINE. HOWEVER, UNIT COULD NOT BE ACTIVATED BY THE BUMP TEST. SUBMITTER STATED THIS IS ABOUT THE 4TH UNIT IN THE LAST YEAR THAT COULD NOT PASS THIS TEST, ALL BEING THIS SAME MODEL. SENT UNIT TO MANUFACTURER FOR REPAIR.