Is the main microphone in the daughter board?

Hi @autoair ,

Use a strong light and a magnifying glass to visually check if the voice inlet hole on the bottom edge of the phone is blocked with lint etc.

If it appears to be blocked (or even not) do not use a pin or probe to try and clear it as you may damage something.

Use a vacuum cleaner and try and suck out any obstruction.

If you still can’t be heard then the microphone is located on the USB charge port board.

Here’ s the iFixit Samsung Galaxy S20 Ultra USB-C Port and Daughterboard Replacement guide.

The microphone can be seen in the image at Step.22 in line with the voice inlet hole.

Replacement microphones (supplier example only to show cost) are available online. Just search for Galaxy S20 Ultra microphone part to get results for suppliers that suit you

Alternatively, replacement boards (supplier example only to show cost) are available online. Just search for Galaxy S20 Ultra USB charge port board to get results for suppliers that suit you