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TV generating noise

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Posted on July 12, 2016 at 10:23:19
jhrlrd
Audiophile

Posts: 135
Joined: October 21, 2014
 I have a plasma TV between my 2 channel setup. When I turn it on to watch
a blue ray, it emits a buzzing noise right from the TV chassis, and is amplified very loudly over the speakers. My first thought was to plug it into a different circuit than the audio gear, but that made no difference.
Secondly, I unplugged the HDMI cable that hooks the TV to the OPPO but that didn't fix it either. I also tried a cheater plug on the TV to no avail.
Would an isolation transformer like a Triplite just for the TV be the solution? thanks

 

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Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 12, 2016 at 10:47:35
Smelly_Socks
 My one question is: does the TV make the buzz if the other equipment is not tuned on?

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 12, 2016 at 10:56:05
jhrlrd
Audiophile

Posts: 135
Joined: October 21, 2014
 Hmm, i never tried powering the TV without powering the other stuff.
I'll try that tonight...
Is this a characteristic of plasma? Does anyone else have one that seemingly buzzes from the screen and stereo speakers?

 

RE: TV generating noise, posted on July 12, 2016 at 14:15:09
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 There is plenty of information about the topic on the web.

See link:

 

I hav a beautiful Sony plasma. it is old (42" cost $4,000 whew, early adopter), posted on July 12, 2016 at 14:15:19
Smelly_Socks
 No noise. I think you have a normal, typical problem of AC grounding.
Something in your setup is grounded 'funny' or one of the components AC wires of hot and neutral is reversed..
So somewhere the bleed of some power, (most likely culprit is a capacitor) is letting some of that to affect the sound.
Lifting the ground someplace is the usual solution. However I suggest you do NOT lift the Plasma TV ground.

If your TV is actually making a physical sound out of the back, that may be a not so good transformer in there.
Or a fan ?? may be overly noisy. (lots of plasma TVs have fans inside to cool them down.)

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 12, 2016 at 23:55:49
jhrlrd
Audiophile

Posts: 135
Joined: October 21, 2014
 Yes, it still makes the buzzing noise from the chassis/screen with the other gear turned off.

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 13, 2016 at 00:50:26
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 Some plasma TVs make noise. It comes from the screen and there's nothing you can do about it. Some manufacturers put out a bulletin about it, Samsung among them I believe. Unless yours is a Hitachi or
Pioneer, it was very likely made by Samsung. Slight chance of it being an LG, but Samsung I think was the one that did most of the rebranding. For example a Zenith is a Samsung IIRC.

Realise what is going on in there. There are many electrical arcs in the screen. They are all of full power, voltage and current. The duration of the arc sets the brightness of each pixel. All these elements are getting switched between plus a couple hundred volts and minus a couple hundred volts. The X and Z sustain boards supply this and are a common failure because they run like an amp that constantly turned up into hard clipping. The transients are terrible and the whole thing is an EMI/FRI nightmare. That's why they have metal backs. They don't use metal unless it is absolutely necessary. If they had a cheap enough conductive plastic there would be no copper on the circuit boards.

If the noise it coming from the screen and it just started a screen failure might be in your near future. If it has always done that don't worry. If you actually CAN tell for sure the noise is coming from the back, that would be rare. Al of them use SMPS technology, there are no transformers running at 60 Hz. In some rare cases a standby transformer, but that would be quite rare. You would have to have some kind of strange model made on Mars or something.

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 13, 2016 at 09:17:22
jhrlrd
Audiophile

Posts: 135
Joined: October 21, 2014
 Update: yes it's a Samsung. The noise is coming from the screen, which is drowned out by the audio. The issue is the same noise is being amplified through the speakers. Having reviewed the link Duster provided, I adjusted the picture settings, finding that the only adjustment that changed anything was the "eco" settings. "high" eco, which dims the screen did change the pitch of the noise to something a little more tolerable.
In the eco settings, there is an option for "screen off", but leaves the TV itself on. This setting eliminates the noise completely.
So that would indicate its not a grounding issue, no?
Just the screen generating noise and getting back on the line.
Forgot to mention, there is a vertical line on the screen which means the screen is indeed pooched. its hardly noticeable while playing a movie.
But I think I'll be on the lookout for a new TV rather than an isolation device.

 

RE: TV generating noise, posted on July 13, 2016 at 12:07:11
SgreenP@MSN.com
Audiophile

Posts: 3538
Joined: April 23, 2007
 most tv's demonstrate this problem....You need a high quality tv, and high quality equipment to eliminate this....I have a Sony with Ayre equipment....quiet.

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 13, 2016 at 18:03:18
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 Yup, they get noisy. There was a bulletin about it but they of course did not offer any refund or partial.

Turning the picture controls down doesn't help because you got those +200 and -200 volts switching all the time, and the pixel is switched on by about a 50 volt grid, or exciter. (do not take these voltage levels to the bank, and in fact they are specified for each unit separately due to differences in each tube manufactured)The pixwl is then turned off at a specifies time by the sustain boards.

All the voltage is still there even if the picture is all black.

Now if getting amplified through the stereo is a new phenomenon I would suspect grounds or filter caps. If you haven't had it hooked up to an amp before and now are just noticing this, it might just be a bad design.

This sounds like one of those tough dogs to fix. To get the hum out of the output audio can be a real PITA. As a Man who can wire a whole house ad has had high end electricians in the family I am not telling you to do this, but cutting the ground pin off the AC cord might help. Don't vut it right away just try one of those adapter thing we all have had to use, and do not connect the ground. This is a test, this eliminates ground current as the fault. If floating the ground works, that means to address the wiring in your house.

Other than that, the very most likely fault is bad grounds or filters in the TV. Actually, if are lucky you might only have to tighten some screws on the circuit boars in the TV, but that is extremely rare. Te thing would have to have been subjected to stress/vibration for that.

 

Can come from everywhere on the TV, posted on July 13, 2016 at 20:59:39
Jon Risch
Bored Member

Posts: 6659
Joined: April 4, 2000
Contributor
  Since: March 1, 1999
 I have a plasma (50" LG) and love the picture.

But it did play havoc with my sound system for the TV, and it took some serious filtering to fix it.

1. AC power line filter on the TV power cord alone, another filter on the stereo as a whole.

2. Physically separating the AC cords from the video and audio signal cables. In your case, make sure the audio cables are as far away (and at right angles if possible where they might need to cross) from any power cords and the video cables.

3. Clamp-on ferrite filters for the AC cords as they exit and enter the TV and receiver.

4. Clamp on ferrite filters on the HDMI signal cables (both ends), as well as the video composite lines. This one cleared up the picture, with blacker blacks and sharper fine detail with less overshoot.

#4 actually did more than I expected, and was the final veil lifted, problems solved.

Jon Risch

 

Ferrite clamp-on filter appearance and sources, posted on July 13, 2016 at 21:17:23
Jon Risch
Bored Member

Posts: 6659
Joined: April 4, 2000
Contributor
  Since: March 1, 1999
 See:
https://www.argentdata.com/catalog/product_info.php?products_id=44

http://www.ebay.com/itm/RFI-EMI-choke-filter-suppressor-ferrite-core-RCT-2T-TOKIN-ESD-SR-15-/320383398212

https://www.dxengineering.com/parts/dxe-csb-525p

http://www.hamcq.com/coax-connectors-ferrite-beads-crimp-tools/ferrite-beads-kits/

http://palomar-engineers.com/rfi-kits/fm-broadcast-rfi-kits

http://www.analogmetric.com/goods.php?id=2074

NOTE: These are a random selection of examples of ferrite clamp-on filters, and is not an endorsement of ANY of these establishments.

Look for clamp-on's with the RFI type rating, and inner diameters suitable for your various cables and cords.

Good luck
Jon Risch

 

RE: Isolate the TV AC power from the other stuff, so IMO yes a Triplite might work., posted on July 13, 2016 at 23:15:49
jhrlrd
Audiophile

Posts: 135
Joined: October 21, 2014
 As I mention in my original post, the first thing I tried was a cheater plug. Didn't help at all. haven't tried ferrites yet. I moved the power cord in and out of proximity of other cords and didn't get a change, but the power cord is tucked away from the audio cords anyway.

 

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