I've had this problem for a while and tried a few things, but before I finally give up I thought I'd ask ALUG about it.
Without headphones plugged in, there is a clear input level showing on the sound settings. With any headphones plugged in, however, none. So I can watch videos or whatever, but it's impossible to use video conferencing tools as no-one can hear me.
Ideas?
Mint 19.1. on a Dell Latitude laptop.
Bev.