Abstract: The constituents and primary working principles of the modulator in transmitting system of the CINRAD/SC new generation weather radar were introduced. The inspection method of trouble and troubleshooting process were described by using an incident of “inverse peak current overflowing” as a case study, and its reason was analyzed. The results indicate that the main reason of this trouble is pulse transformer turn-to-turn short circuit of transmitting system, which leads to mismatch the modulator, and then inverse peak current overflowing increases rapidly. Thus protection resistance is damaged and makes the current relay working, which comes into being “inverse peak current protection” and high voltage is cut off, finally it results in the trouble of “inverse peak current overflowing”. Replacing the pulse transformer iron core and winding, injecting new No.25 transformer oil, various technical indicators are normal after booting test. The troubleshooting method ensures the normal operation of radar system.

Key words: New generation weather radar, Inverse peak current overflowing, Modulator, Fault and elimination