HAM HT Baofeng UV-3R Mic-Volume
From HacDC Wiki
There are several things that can cause built in mic sensitivity to be inadequate.
- some batches have mic gain that is too high caused by poorly adjusted trim pots
- some have it too low due to the same reason
- some have something wrong in the MCU that keeps the gain too low
- some have misaligned case isolation bushing that cover the pin prick mic hole in the case
 Bushing/Case Fix
- invoke your inner caveman
- remove the front panel of the case
- widen the mic hole in the front panel to ~2mm or 3mm (a pocket knife does fine)
- reassemble and test. if it works well stop here else keep going
- remove the front case panel and remove the rubber boot over the electrilet mic.
- use a knife or a hole punch to widen the hole without removing the entire flat face (which is there to help reduce vibrations in the case from getting to the mic).
- reassemble and test if it didn't work it is probably something else or a combination of this and something else.