Do you actually mean buzz - low frequency as in 60 Hz? Or, do you really mean
high pitched whine. If the latter, see the section:
High pitched whine or squeal from TV with no other
symptoms. Or, it may be a combination of both
effects. Is the buzz through the speaker or from the inside of the set?
|NotTaR of Television Sets : Buzzing TV
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- If it is the speaker, then it is a problem with the audio circuitry. This
could be a design issue - very common or an actual fault (if it wasn't there
before). It could also be interference caused by fluorescent lights or
appliances like vacuum cleaners with universal motors or body massagers with
vibrator interrupters (which generate sparks).
Where the source of the problem cannot be located or eliminated, consider
using a (HiFi) VCR for the tuner with an external stereo amplifier and the
disable the internal speaker.
- There is a slight possibility that the AC power in your house has some
harmonic content - the waveform is not sinusoidal. This might be the case
if you try to run on the same circuit as an active dimmer or something else
with thyristor control. Proximity to heavy industry could also cause this.
Relocating the offending device to another branch circuit may help. You
could also try a line conditioner (not just surge suppressor) which includes
filtering. Or, use a HiFi VCR as your audio source (see above). Else,
petition to have that metal foundry move out of the neighborhood :-).
- However, a buzzing that only occurs when the picture has sharply defined
text or graphics, may be an overload problem at the source - some TVs
simply handle it better than others.
If it is a fault in the TV, an adjustment to the tuner or IF may be needed.
(From: Paul Weber (firstname.lastname@example.org).)
Not to disparage proponents of the evil demon theory, but the phenomenon is
more commonly known as "sync buzz". It is caused by poor performance in the
TV's audio circuitry. It can usually be fixed by (1) reducing the signal
strength and/or (2) tweaking the sound IF coil. Unfortunately, some of the
latest TV receivers have no sound IF coil to adjust. If your TV has a sound
IF coil, it can be done by ear, if you don't care about sound quality.
However,I'd recommend taking it so a competent shop and describing the
symptoms. Use the term "sync buzz in the audio," and they'll know what you
mean. Be advised that it can't be cured in some TVs due to poor design.
- If it is from inside the set (and not from the speaker), it is in the
deflection (probably vertical) or power supply. Either of these can vary
in severity with picture content due to the differing current requirements
based on brightness. It could be a power supply transformer, deflection
yoke, or other magnetic component. Even ferrite beads have been caught
buzzing when no one was looking :-). Any of these parts could vibrate if
not anchored securely or as they loosen up with age.
Some hot-melt glue, RTV silicone, or even a strategically wedged toothpick
may help. A new part may or may not quiet it down - the replacement could
See the section: Reducing/eliminating yoke noise.
- Some TVs are simply poorly designed. You cannot infer the severity of this
annoyance from any specifications available to the consumer. It is strictly
a design (e.g. cost) issue. The size of the TV is not a strong indicator of
the severity of the problem but there will be some relationship as the power
levels are higher for larger sets. The best you can do is audition various
TVs very carefully to find one that you are satisfied with.
BTW, when I got my new super-duper RCA Colortrak in 1980, it had a similar
annoying buzz - even had a repair guy out who behaved as though this was to
be expected. I did get used to it and am not even aware of it today - and
still use that set.
(From: Karen (email@example.com).)
Also for some audio buzz problems especially in the older units don't overlook
the possibility of a misaligned trap. or a touch-up of the sound discriminator
may prove helpful.
(From: Alan (firstname.lastname@example.org).)
If the buzz is coming from the speaker suspect a bad saw filter in the if
circuit (very common).
If it is coming from elsewhere in the set it could be the flyback transformer,
line input choke, or most common on those sets - the deflection yoke. I have
repaired many of these yoke by using a wooden shim and some silicone rubber.
In the collar of the yoke just ahead of the lock down clamp, there are some
metal strips under the plastic. These are magnet that are used for convergence
correction at the top and bottom of the picture. If you disturb them too much
it will throw off the convergence.
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