The filament power of SA radar transmitters was tracked in the actual application process, and the causes of the charred power driver circuit board and treatment approaches are described.There are design defects in the protective filament power of the existing SA weather radar transmitter, often leading to destructive faults, especially when the drive signal supply becomes instable, and two half bridge driver switch are often breakdown, resulting in excessive drive currents and burnt circuit boards.Through the actual maintenance and circuit analysis, it is found that this problem can be solved, as long as the self protection function of the filament power supply is appropriately enhanced and the control circuit is improved partially.When the drive signal instability leads to abnormal power output, the filament power receives the signals from the radar system quickly, and strong power supply can be cut off automatically, preventing the high current of the drive signals from passing through the drive circuit to reduce the impact of the filament supply on the switch, so to avoid subsequent devastating failure.The trial operation of the improved filament supply in some radar indicates that the result is satisfactory.