Loud “coil whine” noise from CM4 kit?

Just received it today and booted up for first time just now. Everything seems ok apart from a comically loud coil / electrical whine, almost sounds a bit like the old dot matrix machines.

I’m suspecting a poor connection somewhere, maybe the battery module is not prop inserted into the main board?

Does anyone have any comments?

This is common if you don’t have batteries installed.

Seems to happen when I have it connected to power with batteries in. Could it be a poor contact somewhere?

I had coil whine at power on w/o 18650 batteries, but it seems to have gone away with batteries installed.

It comes back when they are full and you are connected to the power cable