TV giving off high pitch hum.

Well I recently inherited a old TV it is an SDTV and it is about seven years old. So I decided to test it with my computers osciloscope and using the microphone on it i turned the osciloscope on and there was one constant signal that went up and down about 3 or four KHZ every second or two. But when I muted the TV their was the normal background noise at about 1-7 KHZ but one signal that I found is about 16-17 KHZ and 5.94 DB, and when I turn the TV off it stops and that 16-17 signal disapers. So how do I get rid of this annoying high pitch noise?

Picture of TV giving off high pitch hum.
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NachoMahma9 years ago
. My guess is that it's coming from the flyback transformer.
jackillac92 (author)  NachoMahma9 years ago
so is my TV screwed? : (
. Unless you know how to work around high voltage (the CRT stores a BIG charge, even with the power off and unplugged from the wall, and the FBT is connected to the CRT), I'd learn to live with the squeal.
yep CRT works like a capacitor had one laying around, turn on my tesla coil. About half an hour later I was reorganizing stuff and it gave me a nasty bite
jackillac92 (author)  guyfrom7up9 years ago
So if I work with the insides im gonna get shocked?
yep. you need to unplug for a few hours atleast and discharge the high voltage manually the high voltage is made by the flyback transformer - usually it looks like black device in the corner of the circuit board and there are wires exiting from the top of it. one goes to a cap on the side of the CRT. this is the main danger. it can have 30+ KV on it. other 1 or 2 go to the small circuit board on the back of the CRT. they are less dangerous but may still have few KV. dont get near them the board itself contains capacitors that may be charged with up to 400 V. this is less dangerous than the high voltage as it cannot flash to you if you just get near it. dont touch the circuit board or its components and youll be ok there is 'ible how to discharge a CRT TV by Plasmana. note - in the instructable there is something with screwdriver sticked in the ground. dont do it. instead connect the end of the wire to the uncoaed wire with some springs thats on the back of the CRT
. The idea is to have a fairly high-resistance path to Earth. A CRT stores enough energy to melt a wire if discharged quickly. I use a 1-10 Megohm resistor.
hmm yep there is something in it however just a TV laying on the ground is like isolated from it with resistance well above 10 M ohm. when you stick it it does not discharge anything just places the entire TV at 30 KV against the ground creating more danger you do need some path for it to discharge the resistor is the best option. where do you get high power high resistance resistor ?
> however just a TV laying ... . I have no idea what you mean. . . Don't need high-power; 1W works for me. Wattage is not the problem, it's the physical size - HV can arc across a ¼W resistor.
jackillac92 (author)  NachoMahma9 years ago
I have no idea what you guys mean? Can you explain this in lay-mans terms for me? Thanks!
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