A figure measured point potential of 0.7V, B point potential is 0V, C point potential of 2.2V, confirmed that the protection circuit has been activated. A point potential rise causes are: 10V, 140V overvoltage or overcurrent line field output stage. Segmentation method using the circuit were disconnected D832, D857, D451, D551A point potential changes, when disconnecting D832 A point potential drop is 0V, 140V overvoltage protection is a protection circuit elements or caused changes in value. Were removed D832, R831, R830, it was discovered by 11.5kΩ R831 resistance increased to 26kΩ, the aircraft returned to normal after replacing the R831.Uhjservice manual download site