A short circuit of additional diodes can be checked without removing and disassembling the generator according to the circuit shown in fig. 7-9. As well as for checking the valves of the rectifier unit, it is necessary to disconnect the wires from the battery and the generator, remove the protective cover of the generator and disconnect the wire from the output «IN» voltage regulator.
«Plus» batteries through the lamp (1-3W, 12V) attach to output «61» generator, and «minus» - to one of the rectifier unit fastening bolts.
If the lamp lights up, then there is a short circuit in one of the additional diodes. You can find a damaged diode only by removing the rectifier unit and checking each diode individually.
An open in additional diodes can be detected with an oscilloscope by distorting the voltage curve on the plug «61», as well as low voltage (below 14 V) on plug «61» at an average frequency of rotation of the generator rotor.