1. Use a multimeter to test
Set the multimeter to R×1 ohm, and touch the pins of the inductor with two test leads. If the resistance value is much smaller than the normal value, it means that there is a short circuit in the internal circuit of the inductor. If the inductor is infinite when measured, it means that the inductor or the pin is broken. The inductor in the above two situations cannot be used. Finally, for the inductor of the shielding cover, use a multimeter to detect the resistance between the primary and secondary windings and the shielding cover. Touch the shielding cover with one bristle of the multimeter, and the pins of the primary and secondary windings for testing. If the measured resistance value is 0, it means that there is a broken circuit inside. If the resistance value keeps decreasing but is greater than 0, it means leakage. If the resistance value keeps increasing, it means that it is normal.
2. Power-on inspection method
The power transformer can be powered on to check whether the secondary voltage drops. If the secondary voltage drops, it is suspected that there is a local short circuit in the secondary (or primary). When the transformer quickly gets hot or smells like burning or smokes after power is turned on, it can be judged that the transformer must have a local short circuit.
3. Instrument inspection method
You can use a high-frequency Q meter to measure the inductance and its Q value, or use an inductor short-circuit meter to determine the local short circuit of the low-frequency coil. A megohmmeter can be used to measure the power transformer between the primary and secondary.
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