Abstract: Objective To understand the causes of high voltage faults and clarify the idea of equipment failure maintanence through introducing repair cases of new UIH uCT528 high voltage （generator system）, which is conductive to solving users’ problems while reducing maintenance costs. Methods The study achieved understanding of the working principle and interrelationships of uCT528 high voltage by analyzing typical circuit diagrams of repair cases, identifying faulty components, and replacing them. Results Through chip-level maintenance, equipment failures were resolved, maintenance costs were reduced, and maintenance efficiency was improved. Conclusion This typical maintenance case study can provide reference for medical colleagues in dealing with high voltage failures, such as accurately determining high voltage failures, understanding measurement points and circuit diagrams, and clarifying ideas to accurately find faults and repair them.

Key words: High voltage, Filament, Pulse width modulator, Filament adjustment error, Bus voltage