What was found
CLIMBING THROUGH 10,500 FT THE EXCESS CAB ALT WARNING OCCURED. LEVELED OFF AT 11,000 FT. EXECUTED THE QRH EXCESS CAB ALT WARNING CHECKLIST, CAB PRESS MANUEL CONTROL CHECKLIST. COULD NOT CONTROL THE CABIN PRESSURE RETURNED TO DEPARTURE AIRPORT. TRIED SYS 2 CONTROL WITH NO SUCCESS IN CONTROLLING CABIN. ECAM DISPLAY AGREED WITH OVERHEAD PANEL. FOUND CABIN PRESS CONTROLLER SYSTEM 1 FAILING BITE CHECK. REMOVED AND REPLACED 105HM CABIN PRESSURE CONTROLLER, OPS CHECKS GOOD AT THIS TIME. REF AMM 21-31-11-04. REMOVED AND REPLACED RELAY 159GB AS A PRECAUTIONARY MEASURE. REF ESWPM. REMOVED SYSTEM 2 106HM CABIN PRESSURE CONTROLLER AND MARKED BROKEN PIN AND WIRE WITH EXTRACTION TOOL. RETERMINATED PIN 13D AS PER WIRING DIAGRAM 21-31-01. PERFORMED CABIN PRESSURE CONTROL AND MONITORING ADJUSTMENT/TEST AS PER MM 21-31-00-05 OPS CHECK NORMAL.