故障情况: 透视时机器mA表指数在0.5～5mA范围内变化无常;摄片mA时指数时高时低。检修经检查,电源供电,高压变压器初级电路的接线和接点,管电流测量电路、高压整流管及其电路、X线管灯丝加热初级电路均正常。初步确认故障发生在X路管灯丝加热次级电路,它包括加热变压器、高压电缆、X线管以及高压插头、插座等部件。 Failure conditions: When the perspective of the machine, the mA-table index changes in the range of 0.5 to 5mA; when the camera is in mA, the index changes from high to low. After inspection, power supply, high voltage transformer primary circuit wiring and contacts, tube current measurement circuit, high voltage rectifier and its circuit, X-ray tube filament heating primary circuit are normal. The initial confirmation of the failure occurred in the X-tube heating of the filament secondary circuit, which includes heating transformers, high-voltage cables, X-ray tubes and high-voltage plugs, sockets and other components.