I am tuning servos on my Siemens 6sc6101 . After working with the amp on for 30 min. setting drift, I got a fault that shut the servo cards down . The fault was braking resistor overloaded . The machine was designed for 460v , and I had 480v service . I found a 92% transformer and corrected the problem, but the servo cards will not reset . I have all voltages present but enabling does nothing. Any Ideas? Vern Zinn