When a T815-2 dump truck starts, the starting speed is low. The charging indicator is dimmed when the engine starts, but it does not go out. It is obvious that the charging indicator is still on. Troubleshooting: (1) fault causes analysis according to the analysis of the failure phenomenon, the bad fault for the generator, the possible cause of the generator is bad generator, the voltage regulator is bad, the charging line is in bad contact, and the transmission belt is skidding. (2) troubleshooting method first checks power lines and transmission belts, all of which are normal. Check the generator, check the electronic voltage regulator with adjustable DC power, the voltage regulator has good performance, check the armature windings and excitation windings without abnormality. When checking the rectifier, one of the 3 small power rectifier diodes is found to be broken and the failure cause of the charging indicator is not extinguished. (3) troubleshooting measures to replace the damaged small power diode, the generator will be reset, and the charging indicator will return to normal after loading. Fault analysis: in this case, the generator is 9 tube rectifier, and 3 small power diodes have 1 short circuits. When the generator is working, the rectifier voltage will be lower than the voltage of the terminal terminal of the generator armature terminal, which leads to the potential difference between the two ends of the charging indicator, which makes the charging indicator dark, but can not be completely extinguished.