We are working on GE gas turbine 6FA with Ansaldo SFC unit. We are not able to start the unit due to high Generator Voltage indication in the panel meter of 2500V. All the interface input to the unit was isolated but still reading 2500 V at standstill. What checks we can do to solve the issue and any advise where to get spare cards ATAV01 & APROTB of the SFC.