[TenTec] Audio whine when sweep is operated on Omni VII?

[NZ8J]

I just noticed today that when I push the SWP button, there is a high
pitched whine coming out of the speaker when the sweep is running across
the screen.  I've also noticed that when I push the "Band" buttons I
head the same whine when the button is first pushed.

Wonder if anyone else has ever experienced this?  It didn't used to do
this, I've had the radio a month or so. Everything else seems to work
just fine.

Thanks
Tim
NZ8J