noise/interference lines in TV when there is a surge of power

[[email protected]]

Anytime my subwoofer draws a lot of power (or any large appliance in
the house..ie washer\dryer), white dotted lines appear on the TV.
When the subwoofer uses high power during loud scenes, the condition
gets worse showing more pronounced interference lines. I read that
cable grounding could be the issue. But, I disconnected my cable from
the TV...so that only the DVD player is connected. But, I'm still
noticing the problem. Even the TV in the back room shows the
interference lines (to a lesser degree). I've connected the subwoofer
and all my components to a/v surge protectors with line conditioning,
but that doesn't help. Any ideas on how to fix the issue?

Thanks!
PC

 

[Charles Schuler]

Anytime my subwoofer draws a lot of power (or any large appliance in
the house..ie washer\dryer), white dotted lines appear on the TV.
When the subwoofer uses high power during loud scenes, the condition
gets worse showing more pronounced interference lines. I read that
cable grounding could be the issue. But, I disconnected my cable from
the TV...so that only the DVD player is connected. But, I'm still
noticing the problem. Even the TV in the back room shows the
interference lines (to a lesser degree). I've connected the subwoofer
and all my components to a/v surge protectors with line conditioning,
but that doesn't help. Any ideas on how to fix the issue?

1/ Vibration
2/ Marginal house wiring
3/ Poltergeists

 

[Michael Kennedy]

but that doesn't help. Any ideas on how to fix the issue?

1/ Vibration
2/ Marginal house wiring
3/ Poltergeists

LOL! I like #3

 

[Michael Kennedy]

It sounds like you might have a wiring problem in your house. I would try
using a ferrite core on the power input for your tv and dvd player. You
might also try using your tv on a UPS if you have one. Thats what I would
try, but I am definately not an EMI expert.

- Mike

 

[[email protected]]

I just tried connecting a UPS to the subwoofer and the TV....same
result.
I'm starting to think it really may be Poltergeists. lol

Vibration is not an issue...since I'm noticing the interference lines
in back of the house, where the sub cannot be heard.

I also tried connecting the sub to various outlets throughout the
house....with the same result.

Note: Then lines only appear for a brief second when the washer and
dryer kicks on and not visible as the units continue to run. But, the
lines are present anytime the sub produces bass. As I mentioned, the
greater the power...more interference produced.

So, I suspect some type of faulty wiring in the house. So, a call to
a electrician may be in order.

-PC

 

[w_tom]

Even unknown is if interference is via radio waves (over the air),
from cable, or via AC power lines. Will a ferrite bead do anything?
Not for lower frequency noise. Meanwhile, what do you put that ferrite
bead on? Ac electric? Cable? Speaker wires? Or maybe combinations?
Just another example of why shotgun solutions rarely are useful or may
only cure symptoms.

Your first efforts are to find what is and is not reason for problem.
How is the house wired? What connects to that AC mains circuit. What
is the connection relationship between things woofers and 'interfered
with' appliance? For example, that other TV farther away may actually
be electrically closer. You don't know until household wiring is first
defined.

Meanwhile, you are entertaining myths if you think a surge protector
does anything for this. Furthermore, what is this 'line
conditioner'? To be effective, it is how many tens of pounds? Why?
Any smaller 'conditioning' must already be part of the appliance.

Don't entertain myths. Don't change anything with intent to fix it.
Currently, your only concern is to identify symptoms. Solutions come
later. What does and does not change anything? How and how much?
What share same branch circuit and what are not on same AC phase? Of
course, we assume this is post 1960s wiring where safety grounds exist
in all receptacles. Which appliances are two prong or three prong AC
plugs? We must assume because important facts are not yet provided.

For example, what happens when the 'interfered' operates only from a
battery backup UPS without any connection to AC mains. Just another
essential fact to start estimating where interference is coming from.
Note the word estimate - not 'know'.

Another useful testing tool may be:
http://www.schurterinc.com/products/usa/pemfilter.asp
http://www.corcom.com/
http://www.cor.com/PDF/Q.pdf
http://www.interpower.com/ic/p30-35list.asp

http://www.interpower.com/scripts/wsisa.dll/WService=ic/p35list2.p?only_filter=YES

EMC/EMI is an art. Problems can be so complex that conferences of
these industry professionals consist of mostly balding participants.
Your hope for a useful reply is based in information you provide
because useful answers involve that much grasp of technology.

Meanwhile, get rid of the myths. That surge protector does nothing.
What is this 'line conditioner'? Where is this 'ground' that will
somehow eliminate radio frequency noise? The ferrite bead goes where
and does what? What appliances are (may be) missing required filters
(to sell at discounted prices)?

More useful information. What creates interference to an adjacent AM
radio when not tuned to any strong station? If you have that noise,
now you have a tool to trace where that noise does and does not exist.

Do incandescent bulbs dim or brighten when larger appliances start or
stop?

 

[Jim Land]

[email protected] wrote in @f1g2000cwa.googlegroups.com:

I just tried connecting a UPS to the subwoofer and the TV....same
result.
I'm starting to think it really may be Poltergeists. lol

Try connecting the TV to the UPS and then *don't* plug the UPS into the
wall---let it power the TV from its batteries. (That way, you completely
detach the TV from your house wiring.)

Run the sub, the washer, everything that makes the dashed ines. So you
still see the interference?

If so, it's coming through the air.

If not, it's coming through the house wiring.

 

[[email protected]]

I just tried connecting a UPS to the subwoofer and the TV....same
result.
I'm starting to think it really may be Poltergeists. lol

Vibration is not an issue...since I'm noticing the interference lines
in back of the house, where the sub cannot be heard.

I dont think thats logical

I also tried connecting the sub to various outlets throughout the
house....with the same result.

Note: Then lines only appear for a brief second when the washer and
dryer kicks on and not visible as the units continue to run. But, the
lines are present anytime the sub produces bass. As I mentioned, the
greater the power...more interference produced.

So, I suspect some type of faulty wiring in the house. So, a call to
a electrician may be in order.

-PC

It could be any of the following:
rf instability in the amp, (depending on your local tv frequencies)
vibration affecting wiring within the amp, or a nearby appliance, or
some poor house wiring
poor noise suppression on washing machine, fridge etc
weak tv signal may be a contributor to the problem
popular poor quality co-ax

It cant be:
anything to do with power surges.

Getting an electrician in would likely get you nowhere.


NT

 

[Yukio YANO]

Do incandescent bulbs dim or brighten when larger appliances start or
stop?

FLOATING NEUTRAL !!!

If there is a LARGE fluctuation between L1 and L2 and the Neutral Buss,
at the fuse Panel, this would indicate a poorly grounded Neutral on the
Power Pole, a Service Provider problem. or at the fuse panel, a
Customer Problem.

There are rarely Power Surges on domestic power lines except during
Thunder storms ! The so-called surges most people see are Voltage
fluctuation due to un-balanced loads made worse by a bad Neutral
Connection . The incoming 220 does not fluctuate, but due to the to a
bad Neutral connection, the potential between L1 and Neutral and L2 and
Neutral will swing badly with the load. This occurs most often with
Aluminum Wiring, and the cure is to tweek the Ground Straps once in a while.

The incandescent bulbs are the "Poor man's Voltmeter". if you were sure
that the two bulbs in question were on opposite legs of L1 and L2, one
would brighten as the other would dim. There would only be a slight
change in the total Voltage, so not really a "Power Surge" ! Just an
INTERMITTANT noisy connection at the Neutral Buss.

Yukio YANO

 

[[email protected]]

Well, after experimenting some more...let me try to provide some
additional information.

My current setup:
36" CRT Television
DVD player - SVHS output to the A/V
A/V receiver SVHS output to the Television
Cable plug into the TV

In this setup, there are major interference lines in the TV anytime the
subwoofer bass kicks in. This is when I'm watching the DVD video
playing the DVD audio. Now, if I switch the video to the cable input
(while still playing the DVD audio), I do not notice any interference
lines in the TV when the Subwoofer draws powers.

Next, I switch the A/V receiver to play audio from the FM tuner. I
switched the video to display the DVD video. The TV interference lines
still present.

I then changed the setup by taking the DVD SVHS output and going
directly to the TV input (bypassing the receiver). I kept the A/V
receiver audio output on the FM tuner, the interference lines where NO
longer present. I then switch the a/v receiver to the DVD audio, the
interference line were slightly present but only at high volume scenes.

Unplugging the cable from the TV had the same result.

In all cases, the cable video didn't seem to be affected by the
subwoofer. (When I turned on a power drill or large appliance on...in
that cases....a few white specs appear in the tv....but this is very
slight.)

I did notice when I plugged the cable into the TV...the subwoofer makes
a hum/buzz when the subwoofer's volume is turned high. Removing the
cable, I can turn the subwoofer's volume to max and no hum or buzz at
all. So, this may be a different problem. Maybe a ground loop issue?


During all my experiments, there were no diming of the lights in the
house. The speakers play clean without any static.

Note: I did try plugging the TV and DVD player into the UPS and have
it run competely off the battery. But, I'm unable to plug the A\V
receiver and have it run off the battery without causing an overload
condition. I still got the interference lines when playing the DVD
audio thru the receiver as mentioned above.

I'm not sure how the house is wired, so I can't comment on that yet.
House built in the early 80's.

Anyway, hopefully the extra information will help. I'm still unsure
what I should try next to eliminate the problem. Obviously, I can
route the DVD video directly to the TV to minimize the issue...but that
still doesn't correct the problem.

Any help or additional suggestions will be appreciated.
Thanks!
PC