I have no sound from intern speakers from the imac retina 4k 21,5 inch 2017
imac 18,2 i use zorin ultimate 15.3 i have tested with pulsevolume control hdmi out intern on but no sound
Hi, can you issue the command : alsamixer
in terminal and check if you can see your sound card?
i used alsamixer and give this information:
hda intel pch
cirrus logic generic
Quite an old thread, but this might help you:
I wish that nearly decade old post helped... but it didn't. I guess not all oldies are goodies. 
Alas, I'm here with a similar issue. Sound card isn't working on a 2017 27" 5K iMac... Except, unlike the OP, I'm getting "Dummy Output" ... no sound card even being detected. I've already seen the FAQs on the Zorin site regarding this very problem but the one "fix" doesn't actually fix anything.
Alsamixer output looks like this:
I have a zoom call tomorrow and cannot live out sound. Can anyone please help me with this?
Crosslink: