Panasonic pt53wx42f high pitch whine noise

I recently received a pt53wx42f from a friend. it was moved about 40 miles in an upright position.

the tv seems to work pretty well after all that, no convergence issues as best i can tell

however, the tv did seem to pick up an annoying high pitch whine. it pretty high in pitch nearly dog hearing levels, but i can hear it.

the noise seems to go away if i switch to anything without a picture (ie change to an unused input, turn the brightness all the way down)

i had an old sony crt that did the same thing. jiggling the flyback transformer seemed to fix that one. i tried the same trick gently proding the boards in the panasonic, but it didn't seem to effect anything.

does anyone know what else might have come loose or be causing this noise?