annoying noise coming from TV

[MikeF]

Hello all, but especially to Woodman :^)

I have a 1.5 year old Toshiba 27" flat crt tv that just recently has decided to emit a high-pitched noise after the tv has been on for a while. I can usually fix the problem by turning off the tv, waiting a few seconds, and then turning it back on, but this is only a temporary solution as the noise inevitably comes back. I talked with a buddy (an electronics tech) at work and he suggested that it is caused by a vibration at ~16kHz of something in the power supply (I think that is what he told me). He said they have a spray can of a silicone-based product, which when sprayed on the offending component will stop the sound. Does any of this make sense? Of course, the warranty is over (only 1 year) and if there is a reasonably simple fix that I can do myself then that's what I'd like to do. I'll be honest, the noise isn't completely driving me crazy yet, but I think it's only a matter of time . . .

Thanks in advance for your help,
Mike

[midfiguy]

Mike, try plugging the TV into another outlet that is NOT part of the same circuit. I used to get static when playing CDs when using a particular line. This may not be your trouble, but give it a shot.

Are there any other electrics/electronics on or near the TV that may cause some kind of interference?

Don't know much about it, but thought I'd throw some ideas out there.

[MikeF]

Mike, try plugging the TV into another outlet that is NOT part of the same circuit. I used to get static when playing CDs when using a particular line. This may not be your trouble, but give it a shot.

Are there any other electrics/electronics on or near the TV that may cause some kind of interference?

Don't know much about it, but thought I'd throw some ideas out there.

I haven't tried plugging the tv into a different circuit yet (this would entail running a long extension cord from another part of the house). The other electronics near the tv are the receiver, dvd player, vcr, and cable box. Nothing has changed in the setup over the past 5 months, but this problem only emerged within the last month. It's not static or any kind of visible interference on the display, only the annoying high-pitched noise.

Cheers,
Mike

[Hawkeye]

It sounds like it might be the high voltage power supply. If that's the case no amount of spray will help it.....unless you're able to spray out another power supply from the can. I'm no tv technician, so I could be wrong, but I did work on a lot of mid 1980's Sony crt's of graphics displays. Most of the time a high-pitched whistle was remedied with a hvps. Good luck.

[kelsci]

Mike; I defintely think you need Woodman's help on this. I, like some of the others, suspect the high voltage area in your set. I think you are hearing an oscillation noise from a defective part, probably the high voltage rectifier.

[markw]

It's either replace it or live with it.

[MikeF]

It's either replace it or live with it.

I guess that I'll be living with it. Thanks for the info.

Cheers,
Mike

[Kursun]

The good news is that as you grow older you'll not be able to hear it. Meanwhile you can try different seating arrangements as frequencies that high are highly directive.

[markw]

That'll produce a serious whine from ANY tv set. (Oh Mistah Sheffield!)

(just havin' fun. don't get offended.)

[MikeF]

That'll produce a serious whine from ANY tv set. (Oh Mistah Sheffield!)

(just havin' fun. don't get offended.)

Good one . . . but I only said annoying, not obnoxiously abrasive. . . .

:^)

[Kursun]

I remembered after I posted... I did fix our old 26" Philips TV once. What I did was to squeeze in some thin pieces of rubber underneath the flyback transformer (between the ferrite core of the flyback transformer and the printed circuit board). It did do the trick.

[woodman]

MikeF-
Sorry I'm a bit late getting around to answering you on this.

As to ... plugging the set into a different A-C outlet: Fuggitaboudit - there's absolutely no chance whatsoever that that would fix the problem.

Those that pin-point the problem to the high-voltage supply are right on the money ... that's undoubtedly where the problem is coming from. It operates at 15.75kHz, which translates to a pretty high pitched sound to those unfortunate enough to hear it. Most people's hearing has been reduced at frequencies that high - thanks to the plethora of "noise pollution" - not to mention the extremely loud levels of most rock music that we've all been exposed to for a number of years, that they don't even hear the high-pitched whine that's produced in the horizontal sweep circuitry of vast numbers of TV sets.

As to what can be done about it, there's no definitive answer to that. The offending part is most likely the IHVT (the Integrated High-Voltage Transformer). In years gone by, the only "cure" for your problem was to replace the IHVT. If there's been some "silicone-based" product that can be sprayed on it that will stop the noise, I'm not aware of it since it must be a recently marketed product. Sounds like it might be worth a try ... ask your tech friend more about it.

Kursun's suggestion also might be worth pursuing, depending on the transformer's design - how much space is available underneath or around it in which to shove some resilient rubber of some kind in the attempt to dampen the vibrations. But this is apt to be a "shot in the dark" - a "crapshoot", etc.

Sorry that this is about the best I can offer you.

[kfalls]

I had a similar problem with my Pioneer Pro-100 RPTV. The printed circuit board traces for the transformer had gotten hot and compromised the soldered connections. I soldered a piece of wire over the run and resoldered the transformer connections. It's possible there was a cold solder joint which deteriorated over the years causing more resistance, more heat. Worked fine afterwards until the conversion chip went bad.