What was found
1 HR INTO FLIGHT, CABIN PRESSURE EXCEEDED TOLERANCE (AROUND 9.0 ON DEFFERENTIAL PRESSURE) AND BOTH CONTROLLERS FAILED. HAD TO SELECT MANUAL AGAIN TO BRING PRESSURE BACK DOWN. REACTIVED AFT OUTFLOW VALVE IAW MEL21-31-04-01-A, PERFORMED BITE TEST FOUND "AFT VALVE" TEST FAIL ON BOTH CPCS. R & R AFT PUTFLOW VALVE AND TEST ALL SATIS IAW AMM 21-31-12. REGARDING THE CONTINUITY OF THE WIRINGS, FOUND THERE ARE DIODES BETWEEN PN:14A, 14B AND GROUND. BYPASSED THE DIODES, CHECKED WIRINGS NORMAL,TESTED THE DIODES ALOO NORMAL REF ASM 21-31-00.