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In Reply to: Panasonic 27" Superflat XF series TV posted by RT on June 01, 1999 at 08:20:59:
>>I would like to know why this had originally happened.<<Sounds like the switching power supply was whining because you were overdriving the P/S to supply power to the color guns that were running at full blast to put up a white screen. The flyback trannie, HOT, and shadow mask whine as well.
>>I unfortunately fall into the minority of people who can hear the high pitched whine of all the tv's when I go to the store.<<
I wouldn't say unfortunately because you know you can hear those high frequencies. I can hear my roommate's TV whining from a different floor! However, it does sound like his TV is going to go any day now (even though it's been making that awful noise for the past year). He can't hear it because he used to work around jet engines in the USAF.
As for tweaking......I've tried using a blanket wrapped around my tv and it cut down the whining to a tolerable level. I'm not sure it's a good idea because it cuts down on the ventilation of the TV.
Tom S.
Thanks for the information....I'm relatively new to the field of tweaking and optimizing home theater set up.....in regards to my tv - what is a flyback trannie? I'm assuming the HOT is some sort of transformer? Not sure about the shadow mask either. Are any of these parts capable of having a quieter substitute? Also my friend and I were discussing the possibility of using a dampening material such as dynamat on the back of the picture tube. Would this work?
The casing is made of plastic, so I'm not sure how much resonance it is really providing.- RT
> > what is a flyback trannie? < <A high voltage transformer that is usually the most expensive part of the TV besides the tube. Flybacks are "customized" for each television. I wouldn't mess with putting any type of dampening material directly onto the flyback.
> > I'm assuming the HOT is some sort of transformer? < <
Horizontal Output Transistor--probably the most prone to fail component in a television besides the power supply. It gets very hot and usually has biggish heatsinks attached to it. I wouldn't mess around with it.
> > Not sure about the shadow mask either. < <
That is contained inside the tv tube itself. Nothing you can do about it.
Maybe putting some dynamat or other damping material on the outside of the TV case will help but you have to have circulation for the components inside the TV (don't block the vents).
Estes made a good point about the wood cases of older TV's. I don't seem to
notice the whining of TV's in wooden entertainment centers as much as I do the TV's that are in the open.Tom S.
Plastic is a wonderful resonator. You could try putting a thick blanket around the case to see it helps. The problem of course is that the vent holes are now blocked.
I think part of the reason you hear the whine, as loud as you do is the case also vibrates. Old TVs had a wooden case, not plastic, so you could only hear the whine if you were up close. I have my TV on a Target style stand and that seems to help.
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