1,speakers,headphones,moving coil microphone:R x 1 Ω file,any pens and connect one end,another pens and touch point at the other end,normal when ringing sound "da" sound. If you 8500w gasoline generator don't ring,is the coil is broken,if the noise small,sharp,is a brush ring problem,also cannot use.2,measuring capacitance,resistance,according to choose the proper range of capacitance,and pay attention to the measurement for the electrolytic capacitor black pens and to answer the capacitor anode. (1) and microwave method to estimate the size of the capacitance level:but by experience or reference standard permanent magnet motor capacitance of the same capacity,according to the most greatly to determine pointer swing. Refers to pressure values of capacitance,as well as long as the same capacity,such as estimated one 100 mu F / 100 v capacitance can be used a 100 mu F / 25 v capacitance to the reference,as long as they are of the same pointer swing the biggest,as can be concluded that capacity. 
(2),estimated skin level capacitance size:to use R x 10 k Ω file,but only to over 1000 pf capacitance measurement. Capacitance of pf 1000 or older,whose hands slightly swing,as long as you can think capacity is enough. (3),whether the capacitor leakage measurement:the one thousand micro capacitance method above,can use first R x 10 Ω file its quick charge,and preliminarily estimate the capacitance,then change to the R x 1 k Ω file continue to test for a while,then the pointer should not return,and shall be parked at or very close up,or have a wholesalemotor.blogspot.com leakage phenomenon. To timing or oscillation under some dozens of MFD capacitor (such as color TV switch power oscillation capacitance),high efficiency electric motor and the leakage characteristic requirement is very high,can't be used as long as a slight leakage,then can be in R x 1 k Ω file again after filling the electric switch to R x 10 k Ω file continue measurement,whose hands should be parked in the same up and not return.
