Inoperability of the microphone can be caused by a malfunction of both itself and the device to which it is connected. Also, it may not work when connected to serviceable, but incompatible or incorrectly configured equipment.
If the microphone is dynamic, first check the position of the switch located on it. Then disconnect the microphone from the jack, then connect an ohmmeter to the plug. In the on position of the switch, the resistance of the voice coil should be several tens of ohms, and in the off position it should be short-circuited by the switch. If you find an open circuit, ring the cable and voice coil separately, and if you find a short circuit, check the switch and also the cable.
A dynamic microphone with a DIN plug may not work if the plug is wired to the old standard and the jack is wired to the new, or vice versa. The common contact in such a socket is always the middle one, but the signal contact can be both right and left. Solder the plug if necessary.
The electret microphone does not have a switch. It should only be called with a digital device, since an analog one can burn the field-effect transistor built into the microphone capsule. The resistance between the contacts of the plug must be from 500 to 5000 Ohm, and it can vary depending on the polarity of the connection of the probes. If an open or short is detected, proceed as described above. If the microphone capsule has to be replaced, ensure correct polarity when plugging in the new one. When repairing any microphones, both dynamic and electret, do not solder when the plug is inserted into the socket.
A working microphone may not work if the recording level control on the tape recorder is set to zero, and the sensitivity control on the karaoke system. Check their position and adjust if necessary. Also, the sound can be very quiet if a dynamic one is connected to a device designed for an electret microphone. The same result is possible by connecting a 3-volt electret microphone capsule to a 1.5-volt device. If the device is designed for a dynamic microphone, the electret will not work with it at all.
If a working microphone connected to the computer does not work, first check the settings of the software mixer. Note that in the mixers of some operating systems, a checkmark may mean the enabled state of the corresponding input, while in others it may be disabled. If manipulations with the mixer do not lead to success, check that the microphone plug is inserted into the jack (it should be green). If this does not help, make sure that the sound card is working properly and correctly configured.
