Constant high-pitched noise in Kenmore Microwave

Kenmore microwave model 111.71613810 makes a continuous high-pitched noise coming from area behind the clock and light. The noise is not loud and is easier to hear when door is open. Seems to be related to the clock because it was a bit louder when the clock is set. I thought to troubleshoot it myself but the screws are not standard. I’ve had it for over a year and am close to dumping it because it’s so annoying. I’d be grateful for any help!