the horizontal output stage is the typical offender .
"singing" components may be located with a gentle nudge with an insulated probe while listening for any change
in sound . installing,wedges,shims,glue to the offending part MIGHT provide a cure.
using NTSC , the operative frequency is 15.734Khz.
this is within the human auditory range . scan freqs above 20Khz are unheard.
as men age, the high end reception drops off considerably.
as such, i am no longer able to hear a 15Khz tone .