Red or Green spots appearing on TV tube (coming from an elevator???)

[Hans-Martin Krober]

Hi,

my girl friend just moved into a loft. She got a new Philips 27" flat
screen tube TV. Once in a while there are color spots appearing when
you watch TV. Usually they are in one corner and grow and shrink a
little bit. They are usually green or red. So the TV picture basically
changes to a red or green round spot in one corner of the TV. Turning
it off and on fixes it. I assume it has something to do with magnetic
fields. We exchanged the TV but the same thing happens. She has
speakers to the left and right. But we moved them further away and
they are supposed to be shielded. Plus it happens also when the stereo
is off.

Now my real question is: behind the wall (concrete) where the TV is
standing there is the elevator going up and down. Could electric
motors on the elevator cause such a problem? Or is it more likely that
it is again the Philips TV? Maybe we should try another brand. Any
advice would be appreciated.

Thanks,
Hans-Martin

[Mikey]

With speakers, it doesn't matter if the stereo is on or off, there is
still a magnetic field from the permanent magnets in the speakers.
Your elevator theory sounds possible. In all elevators (that I know of)
the motor is mounted in a room on the roof or in the basement and the
only motor on the elevator car may be a ventilation fan.
The elevator car itself is probably made mostly out of metal, and there
are heavy metal counter-weights which move the opposite direction of the
car. Depending on the thickness of the wall and type of metals used the
elevator certainly could be causing the problem. Maybe even the
high-amperage wiring to the elevator's motor runs through or behind that
wall and is producing a magnetic field.
One way to tell is to watch the TV and listen for movement of the
elevator and see if it directly affects the color. Or you could try
moving the TV as far as possible from that wall and see if it is
affected the same way.
Any other nearby electrical device can cause problems. The power
transformer in a stereo or the ballast in fluorescent light fixture can
sometimes cause the same symptoms if it too close.
Whether or not another brand of TV would react the same way is difficult
to determine. Some TVs may be more or less sensitive to the nearby
magnetic field. If the elevator is found to be the cause of the
problem, your only option may be to rearrange the room to allow the TV
to be located as far as possible from that wall.

[Dave D]

"Mikey" <michael...@mail.verizon.net> wrote in message
news:3C2128EA...@mail.verizon.net...

> With speakers, it doesn't matter if the stereo is on or off, there is
> still a magnetic field from the permanent magnets in the speakers.
> Your elevator theory sounds possible. In all elevators (that I know of)
> the motor is mounted in a room on the roof or in the basement and the
> only motor on the elevator car may be a ventilation fan.
> The elevator car itself is probably made mostly out of metal, and there
> are heavy metal counter-weights which move the opposite direction of the
> car. Depending on the thickness of the wall and type of metals used the
> elevator certainly could be causing the problem. Maybe even the
> high-amperage wiring to the elevator's motor runs through or behind that
> wall and is producing a magnetic field.
> One way to tell is to watch the TV and listen for movement of the
> elevator and see if it directly affects the color. Or you could try
> moving the TV as far as possible from that wall and see if it is
> affected the same way.
> Any other nearby electrical device can cause problems. The power
> transformer in a stereo or the ballast in fluorescent light fixture can
> sometimes cause the same symptoms if it too close.
> Whether or not another brand of TV would react the same way is difficult
> to determine. Some TVs may be more or less sensitive to the nearby
> magnetic field. If the elevator is found to be the cause of the
> problem, your only option may be to rearrange the room to allow the TV
> to be located as far as possible from that wall.
>

Yes, magnetic fields are strange things. The monitor I'm looking at now has
a "shimmer" on it as though it were right next to a mains transformer. I can
move the monitor quite a distance with no change but if I put it in another
room it's perfect. I still haven't come up with a rational explanation as to
what is causing this. There are no motors or high-current mains cables
nearby and moving the speakers has no effect. The strange thing is, it's a
20" Sony Trinitron, built in a metal cage etc. so I'd expect it to be pretty
resistant to this sort of thing.

Regards

Dave

[Sam Goldwasser]

"Dave D" <dav...@somewhere.com> writes:

> Yes, magnetic fields are strange things. The monitor I'm looking at now has
> a "shimmer" on it as though it were right next to a mains transformer. I can
> move the monitor quite a distance with no change but if I put it in another
> room it's perfect. I still haven't come up with a rational explanation as to
> what is causing this. There are no motors or high-current mains cables
> nearby and moving the speakers has no effect. The strange thing is, it's a
> 20" Sony Trinitron, built in a metal cage etc. so I'd expect it to be pretty
> resistant to this sort of thing.

What about fluorescent lamps nearby or in the ceiling? Also could be
unpaired wiring in the floor, ceiling, or wall.

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[H. Dziardziel]

>Hans-Martin Krober wrote:
>
>> Hi,
>>
>> my girl friend just moved into a loft. She got a new Philips 27" flat
>> screen tube TV. Once in a while there are color spots appearing when
>> you watch TV. Usually they are in one corner and grow and shrink a
>> little bit. They are usually green or red. So the TV picture basically
>> changes to a red or green round spot in one corner of the TV. Turning
>> it off and on fixes it. I assume it has something to do with magnetic
>> fields. We exchanged the TV but the same thing happens. She has
>> speakers to the left and right. But we moved them further away and
>> they are supposed to be shielded. Plus it happens also when the stereo
>> is off.
>>
>> Now my real question is: behind the wall (concrete) where the TV is
>> standing there is the elevator going up and down. Could electric
>> motors on the elevator cause such a problem? Or is it more likely that
>> it is again the Philips TV? Maybe we should try another brand. Any
>> advice would be appreciated.
>>
>> Thanks,
>> Hans-Martin
>>
>

I understand some elevators use dc motors so the magnetic fields
in the cables could be high especially at start up. Even an ac
motor suddenly turned off could generate large fields. Move the
tv away or at an angle to see what happens.

[David]

The elevator at our hospital uses 2 guage wire. Yes, 2 guage wire.
This is for the 60 to 100 amp start up surge of the motor.
Some elevators do have the motor on top of the car as well.

I would suspect this as the cause of the changing colors.
Move the tv to a different wall.
David

h...@operamail.com (H. Dziardziel) wrote in message news:<3c234c9b...@news.kornet.net>...