What was found
WHILE TROUBLESHOOTING APU FAIL CAS MESSAGE, DISCOVERED BURNT EPDC #2 EMITTING AN ELECTRICAL SMELL. UPON ACCESS PANEL REMOVAL, FOUND SEVERAL CONTACTORS COVERED WITH SOOT. REMOVED AND REPLACED EPDC #2. OPS CHECKS GOOD IAW 24-61-70. FOUND THAT THE REMOVED EPDC WAS POSSIBLY STUCK CAUSING ELECTRICAL DAMAGE. EARLY INDICATIONS POINT TO FAILURES ONLY OCCURRING WHILE CONTACTOR (P/N 107CC05Y03) IS MOUNTED IN THE EPCD 2 ASSY.