Why do TVs make high-pitch noises after a year or 2? (1 Viewer)

[Oren]

Why do TVs make high-pitch noises after a year or 2? It drives me crazy. My RCA did it something fierce, but my Sony didn't, but then my (current) Phillips does it.

The type of noise I'm talking about is little, high pitched "electronic" noises emanating from the electronics (i.e., not the speakers).

 

[Jack Briggs]

Nearly all televisions put out a high-frequency (around 15 kHz) tone when they are running. Some of us are more sensitive to it than others (I sure am); some cannot hear the tone at all. It's normal.

 

[ChuckSolo]

All I know is that my old Sony 27" TV started doing this (audible high pitched sound) and died within a few months.

 

[Cary_H]

I had an RCA unit that did it from day one. The dealer made several attempts to resolve it, and were never successful. They did manage to cause a number of new problems along the way though.
Many years later this set died. The fix was cheap and since I wasn't prepared to retire it despite it's old age, I gave them the go-ahead.
This repair eliminated the squeal. They had replaced one of the high-output transformers. It seems as though the original created some sort of resonance within.

 

[Andrew Lillie]

I have always suspected that it might be the electrolytic capacitors drying out in the timing circuitry. As these caps dry, their effective capacitance changes and thus the timing, which might become audible. A lot of CRTs "die" because these caps die, and they are cheap to replace.
My theory anyway.
Andrew