First check all microphones one by one to see if there is any obvious damage, then shake the microphone to confirm if there are any loose parts on the microphone.
The second is to check and maintain the microphone connector and pins. You can use the "oil-free compression spray gun" or "dust-removing compressed gas tank" to blow away the dust and small gravel in the microphone connector.
Next, plug each microphone into the PA separately to see if they work properly.
In our experience, the most common problems encountered when cleaning microphones are: dirty microphone components and recessed microphone grilles.
Removal of dirt is not a difficult task-you just need to put all the dirty components together and let them clean them thoroughly. Pick out components that are sunken or obviously broken.
When cleaning the microphone grille, we use mouthwash and brush with a toothbrush. Alternatively, you can also use a 1: 1 mixed solution of distilled water and isopropyl alcohol as a cleaning agent. If you encounter dirt that clogs the grille, you can use a compressed air spray gun to blow off the dirt, and then put it on a towel to dry.
If there is a slight depression on the microphone grille, although it may not affect the performance of the microphone, it looks very unsightly. If the dents of the grille are too severe, it may cause interference to the airflow, and may also touch other components inside the microphone, resulting in increased noise of the microphone, and even damage to the microphone internal components and the diaphragm.