no sound from output or speakers

The headphone socket has a small switch inside so when you remove the plug the internal speaker is driven. It sounds like you may have a dirty switch or damaged it with a mis-shaped plug or just from a lot of use. Using a dentist probe and a magnifier see if the switch is working and if needed try cleaning it. In some cases the switch shifts so the contacts don't touch using a toothpick try rotating back the contact. Use the Mic outlet as a guide as it's the same socket.