For common inductor, We usually adopt the following three measurement methods:
1)DC resistance measurement method: use the resistance of the multimeter to measure the antenna coil, oscillation coil, midcycle, input and output transformer coil DC resistance value, you can judge the quality of these inductive components. When measuring antenna coil and oscillation coil, the measuring range should be placed at R×10Ω; When measuring the circumference and the output and input transformer, the range should be placed in R×10Ω or R×100Ω;
The measured resistance value is compared with the maintenance data and my daily accumulated experience data. If it is very close, it means that the tested component is normal. If the resistance value is much smaller than the empirical data, it indicates that the coil has a local short circuit; If the resistance is zero, the coil is short-circuited.
2)the power inspection method: the power transformer can be energized to check whether the secondary voltage drops, such as secondary voltage reduction is suspected secondary (or primary) local short circuit. When the power appears after the transformer quickly hot or burnt smell, smoke and other phenomena, it can be determined that the transformer must have a local short circuit, this time is not suitable for measurement.
3)Instrument inspection method: can use high frequency Q table to measure the inductance and Q value, can also use inductance short circuit instrument to judge the local short circuit phenomenon of low frequency coil. Megohm meter can be used to measure the insulation resistance between the primary and secondary power transformer.