MC2180 Scanning audio feedback disappear

Hi Zebra community,

We have 17 scanner guns of MC2180, it working great to support our needs during our trade-show and also work great at our warehouse for inventory taking and order picking.

The last 2 guns we bought was direct from Zebra, as the previous ones still using "Motorola" in the screen top label.

We have an issue with 1 of the latest gun which the audio feedback (beep) disappear when we scan a barcode; we tried many ways to find how to turn back by checking the volume up button, also the settings at the control panel. But still no luck to find out how to set back the audio feedback when the scanning light-up.

Anyone experience with similar issue and the idea of the solution?

Thank you in advance.