On your KDE/Plasma desktop, click the Application Launcher in the lower left corner, click System Settings, and then scroll down the list to Multimedia. On the Multimedia window, first click the second item, Audio Volume, then on the Devices tab, make sure the Outputs item is Audio Analog Stereo, and that it is not muted, and the port is Speakers.
Then, still under Multimedia, click the third item, Audio and Video. On the Device Preference tab, click Music, and look in the right-hand window. There you should see at least two items, Dummy Output and Built-In Audio Analog Stereo. You want to highlight Built-In Audio Analog Stereo, and if it is not at the top of the list, move it up by clicking the Prefer arrow button at the lower right. When it is highlighted, click the "Test" button on the lower right, and it should play the chimes. If you changed anything to make it work, click the green "Apply" button. The same Built-In Audio Analog Stereo device should be shown under Audio Recording in each item.