AN AVIONICS SHOP TECHNICIAN RPTS UPDATED ACARS MGMT UNITS COULD NOT BE INSTALLED DUE TO INCORRECT ACCOMPLISHMENT OF AN ENGINEERING ORDER TO CHANGE THE MOUNTING RACK KEYWAY.

Narrative

ON FEB/TUE/03; XYZ WAS ASSIGNED TO PERFORM EO (ENGINEERING ORDER; SOFTWARE UPGRADE) ON ACFT X. WHILE PERFORMING ENGINEERING ORDER THEY WERE REQUIRED TO REPLACE THE ACARS MU (MGMNT UNIT). THE NEW MGMNT UNIT COULD NOT BE INSTALLED DUE ACFT BEING KEYED INCORRECTLY. OLD MGMNT UNIT WAS REINSTALLED; ENGINEERING ORDER WAS DEFERRED UNTIL ACFT WAS KEYED CORRECTLY. ON DEC/SAT/02; ACFT X'S ENGINEERING ORDER WAS ACCOMPLISHED BY YZZ. THE ACFT X SHOULD HAVE BEEN CORRECTLY KEYED THEN. XYZ ATTEMPTED TO CHANGE UNIT AND FOUND ACFT WAS KEYED INCORRECTLY. ON FEB/FRI/03; MGMNT UNIT WAS REMOVED FROM ACFT X AND SENT TO AVIONICS SHOP. I PERFORMED SOFTWARE UPDATE (ENGINEERING SVC ORDER REVISION AG) ALSO FOUND COLD SOLDER JOINT ON PWR SUPPLY CONNECTOR (INTERNAL CONNECTOR). I MADE ALL REPAIRS. I DID NOT HAVE TO RE-KEY THIS MGMNT UNIT. IT INSTALLED NORMALLY ON MY SHOP TEST SET. I DID NOT LOOK AT KEYING ON THE MAIN CONNECTOR BECAUSE THE REQUEST CAME AFTER I HAD RETURNED UNIT TO SVC. THIS COULD HAVE BEEN CONFIRMED IF THE REQUEST WAS ON THE SERVICEABLE PARTS TAG.