I'm trying to figure out my dad's laptop. I've set him up with Kubuntu a while back...It worked well for a long time. He even manages updates on his own for the most part, with only occasional help. One update however removed the volume controls...
The widget is in the systray, but no devices or apps are listed despite the sound card being usable. Audio Volume in the system settings likewise shows no configuration settings despite devices showing up under Audio and Video for playback.
He's running Xenial still.
Googling just finds results over the Volume Widget missing.