If its the Precharge Voltage error, look at the circuit breaker CB1 underneath the system. That has a tendancy to get tripped by accident. You cannot normally see CB1 without using a mirror because it is located on the bottom of the Capacitor/Power Module an inch or so off the floor. You can locate and operate CB1 by feeling underneath the Capacitor/Power Module. Open the breaker by positioning the handle toward the rear of the C-Arm. Close the breaker by moving the handle toward the front of the C-Arm. The breaker handle goes to the middle position when the breaker trips. Reset CB1 by moving the handle to the open position and then to the closed position Also This message appears when the voltage on the generator’s precharge capacitors exceeds 250 Volts. This voltage check occurs during bootup, and shuts down the system immediately if there is a problem. This error can occur if the system has been connected to AC but unused for a long period of time, in which the batteries become overcharged. Draining some charge from the batteries has been shown in the past to correct this error
Overvoltage error is the high voltage tank and possible snubber pcb.
Filament voltage error, If the wrong voltage is applied to the filament, the mA will also be wrong. Filament B plus wrong, duty ratio of filament drive pulses wrong, wrong filament selected, failure of filament regulation, sensor gain wrong. Filament voltage is monitored by an RMS to DC converter on the Generator Driver PCB, and fed to the Filament Driver PCB. If the wrong voltage occurs at FIL_VOLT relative to FIL_VOLT_REF, this is observed by the X-Ray Controller PCB. A fault in the RMS converter or the cable from the Filament Driver PCB might also result in the wrong voltage at FIL_VOLT, but there is also a filament current sense circuit, which will confirm the error. If there is an incorrect gain, this could be caused by the wrong filament relay selection or a problem in the relay which is on the Filament Driver PCB, but if the wrong filament selection is made, the SM_FIL_ACK* signal will be in the wrong state. Additionally, the mA is sensed on the HV Supply Regulator PCB, providing an independent check on the correctness of the filament drive. Other faults in the Filament Driver PCB such as wrong FIL_B_PLUS voltage are also monitored by software.