Toshiba Aquilion 64: 'over kV' error on the high-voltage generator
What happened
A Toshiba Aquilion 64 CT kept reporting an 'over kV' error, pointing to the high-voltage side of the generator.
What was checked
- The error pointed to the HV generator area, so attention went to the voltage multiplier and its supply.
- The 24 V power supply feeding the HV multiplier was checked and, as reported in the case, proved to be the faulty part.
Cause
A faulty 24 V power supply feeding the high-voltage multiplier was the cause of the 'over kV' error in this case.
What was done
The 24 V power supply feeding the HV multiplier was replaced; the error cleared and the diagnosis was confirmed in this case.
Safety
Before opening the generator cabinet, isolate the CT from the mains and follow the manufacturer's high-voltage discharge procedure — multiplier and generator capacitors can hold a lethal charge long after power-off.
Lesson: An 'over kV' error on a CT does not always mean a failed multiplier or tube — check the simple supply rails feeding the HV stages, such as the 24 V line, first.
Covered in the course: CT Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.