Cambridge Soundworks Microworks speaker sound off and on

Stereo sound from both speakers and suddenly the sound drops from one speaker. Adjusting the volume control doesn't seem to get it back on; however, adjusting it while both speakers are working can stop sound on one speaker. It's always the same speaker side but not the speaker itself as I've switched them to test. Its not the wiring because I've tested that too.

Could it be bad 3.5 mm mini plugs? There are actually two audio jacks on the subwoofer and switching the speaker wire between them doesn't correct the situation.

I appreciate knowledgeable advice. Thank you.