Thanx, waross, I'll try to do it..
alehman, I've replaced 3 CDVRs, but at the ending it was the same result. Yeah it's a PMG exciter.. Metering with megohmmeter I have found that any insulation in main field and in exiter field was correct. Metering with multimeter I the test of main field, diodes, exiter was correct too..
One more question.This genset has very big vibration.. Can't it be a problem with main rotor???