What was found
C HYD DEM PUMP EICAS. PUMP WILL ONLY DELIVER NO MORE THAN 2000 PSI. REPLACED ADP REF MM. NO HELP. APU NOW SURGING WITH ADP IN AUTO AND IN MANUAL WITH NO HYD PRESSURE, NO PRESS LIGHT IN AUTO, BUT IN MANUAL LIGHT COMES ON. CHECKED CONNECTOR D488 PINS 6, 12 HAD 28 VDC PINS 3, 4 ARE GROUND. ADP MODULATING VALVE REPLACED, NO CHANGE. TRIED NEW OVERSPEED CARD M1057, NO CHANGE. PUT BACK OLD OVERSPEED CARD M1057. DOES NOT COME ONLINE PERIOD. FOUND INDICATION TO BE READING NORMAL ON APU BLEED.DUE TO HISTORY REPLACED M1057, GROUND CHECKS NORMAL.