I had a similar with a 1979 Silvana console set i owned in the 90s.. All CRT tvs have ghosting which alot of people don't have the ability to hear the high pitch ringing. Mine would do it much louder than normal, upon warm up, and the problem was the suckion cup was loose.. I also had a old Panasonic Quasar same model set as pictured
back in 1991 a customer my mother was working for gave to her. One night watching it, it all of a sudden sounded like a bottle rocket fire cracker was lit and went off along with the high pitch ringing and of course the set went blank, still the audio was on, and the gases really smelled which at the time i thought it smelled just like gun powder.. To this day i wonder what caused that to happen with eruption, boy did i jump through the roof when hearing that..