What was found
DOOR 4 LEFT SLIDE PRESSURE LIGHT ON. CHECK OF SLIDE PRESSURE WITH OHM METER SHOWS 0 WHICH IS A BAD SLIDE. *S/D* THE SLIDE FROM AC 3056 WAS ROBBED AND INSTALLED ON AC 3058. WHEN 3058 LATER RETURNED TO ORD, THE SLIDE WAS REMOVED, A SERVICEABLE SLIDE WAS INSTALLED AND THE SLIDE OFF, WAS REINSTALLED ON AC 3056 (WHICH WAS BEING PREPPED FOR RETIREMENT). THE ORIGINAL SLIDE WHICH FAILED FROM 3058 WAS DUE TO A LOW BOTTLE READING. EG IS UNABLE TO PERFORM A FAILURE ANALYSIS, BECAUSE THE SLIDE AND THE AC ARE RETIRED IN THE DESERT. THE FAILED SLIDE WAS CHECKED A SECOND TIME WITH A SIMPSON 260 METER, AND THE SLIDE CHECKED OK.