Typically a high-pitched whine from a CRT is from the flyback transformer. I found, when I was a kid, that sometimes a well-placed whack on the CRT's cabinet co

Typically a high-pitched whine from a CRT is from the flyback transformer. I found, when I was a kid, that sometimes a well-placed whack on the CRT's cabinet could temporarily fix the problem. Nowadays, I have no idea if I can hear that whine anymore or not, as CRTs are quite uncommon. Probably not. Much for the better, as it used to give me headaches.