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Discussion Starter · #1 ·
Hi guys. Hoping someone can help as I am spending money to solve this and thought I was getting somewhere but have discovered I am not.

I have a 55" Hisense LED TV. Its a 50K390PAD if you must know.

Anyway. I have a portable window air conditioner / conditioning that's brand new a works great. It's summer and I'm in Australia so yes I do really need it on with the temp's we get in Queensland.

The issue is when the compressor switches on or off the TV signal is interfered with, appearing almost like you knock the antenna over and stand it back up. I am also paranoid about this possibly doing damage to the TV eventually as I think its more of a power spike thing than a reception thing.

Now the power for the air con is on a different power point. I cannot say different circuit as I do not know the house circuit schematics, but its not drawing from the same power point.

So anyway, I went and bought a UPS battery back up hoping that if the TV ran off that it would clean up the power signal to the TV.

It is still happening, just not as bad. It's still enough to make the sound go away for a second and the picture to jump. I'd say about half as bad as what it was.

How do I stop this happening?? The UPS just cost me $130 so I am a bit peeved that this did not solve the issue.
 

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Move your antenna as far away from the A/C unit as possible. The motor start circuit is radiating RF energy that the antenna is picking up, the interference is not coming through your mains.

Check your fly lead, if one is being used, and make sure it's well shielded and of good quality.
 

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This sounds like the air conditioner has a high start-up current and is causing a brief but large voltage drop. Plug an incandescent light bulb into the same outlet as the TV and see if it dims when the compressor comes on. If it does then that's what's happening. If not then it is an RF problem. If it's a voltage drop problem then the TV and the AC are probably on the same circuit and one needs to be changed.
 

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Discussion Starter · #5 ·
Thanks so much for the tips guys. I will def look into both.

I am using rabbit ears as I live very close to the TV stations.
At one stage I had tried one of those amplified antenna's which was a mistake as all it did was make the signal too strong. However where the antenna is plugged in, there is an exposed connector left over from the amp (where the amp used to intersect into the fly lead).

I might go see if I can by a good shielded fly lead and take the old garbage off to see if I can shield it as much as I can. It's a room so there's only 'so far' I can get away from the air con. So if it's RF then I am going to have to go down the road of shielding.

I will grab a lamp and plug it into the circuit of the TV and watch it to see what happens with voltage. I was sure it was a voltage drop from the compressor, but RF makes sense as well. So investigating both makes sense.

I will report back in a day (it's 2am - past my bed time here). :rolleyes:

Thanks again. :D :eek: :cool: :confused: :(
 

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Can you run the TV off the UPS by battery power alone (without the UPS connected to the mains) for testing? That will tell you 100% if its RFI or a power surge delivered via the mains.
 
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I would attack the problem at the SOURCE....the A/C....by adding a high quality RFI/EMI Filter....which is available as an in-line product....or included in SOME Surge Protectors....or you can order with pigtails (or built into the Chassis Power Socket) for installation INSIDE the A/C.

I checked Australian JACKSON and POWERLEADER products that claim an RFI/EMI Filter is built-in, but could NOT uncover any SPECS....perhaps the package has them. Here in the US, GOOD 120 VAC Power Strips provide 60-75 dB suppression below 100 MHz and AT LEAST 45 dB in UHF Band...and the CHEAP RFI/EMI Filter products don't have specs, so they don't WANT you to know how mediocre they might be (you usually DO get what you pay for):
http://www.ji.com.au/products/PT0811
http://www.ji.com.au/pdfs/PT0333_DATASHEET.pdf
http://www.ji.com.au/pdfs/PT8888_DATASHEET.pdf
http://www.powerleader.com.au/pdfs/L54000_DATASHEET.pdf

You might also want to check Amateur Radio sources for in-line power RFI/EMI Filters, with NO Surge Protection MOV's.

Since the A/C has a large in-rush current when it turns ON....be sure the current rating of the Surge Protector or RFI/EMI Filter is about TEN TIMES the published RUNNING current rating for the A/C.
 
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Discussion Starter · #10 · (Edited)
Well it is resolved now.

I ended up making my own EMI / Av line filter from parts I purchased at JayCay at Aspley. I bought an EMI filter, standard 240 volt cable, safety box and some crimps. Put it all together and ran the TV's power through that.

As an additional I also purchased some copper RF blocking tape and wraped some around the antenna connections near the TV.

I also bought a 4G in line filter for the antenna. This was probably over kill but it wasn't expensive and I do have a 4G phone. I wasn't getting 4G interference but thought while I was at it may as well be complete.

Attached some images. :eek:
 

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Discussion Starter · #11 ·
I would attack the problem at the SOURCE....the A/C....by adding a high quality RFI/EMI Filter....which is available as an in-line product....or included in SOME Surge Protectors....or you can order with pigtails (or built into the Chassis Power Socket) for installation INSIDE the A/C.

I checked Australian JACKSON and POWERLEADER products that claim an RFI/EMI Filter is built-in, but could NOT uncover any SPECS....perhaps the package has them. Here in the US, GOOD 120 VAC Power Strips provide 60-75 dB suppression below 100 MHz and AT LEAST 45 dB in UHF Band...and the CHEAP RFI/EMI Filter products don't have specs, so they don't WANT you to know how mediocre they might be (you usually DO get what you pay for):
http://www.ji.com.au/products/PT0811
http://www.ji.com.au/pdfs/PT0333_DATASHEET.pdf
http://www.ji.com.au/pdfs/PT8888_DATASHEET.pdf
http://www.powerleader.com.au/pdfs/L54000_DATASHEET.pdf

You might also want to check Amateur Radio sources for in-line power RFI/EMI Filters, with NO Surge Protection MOV's.

Since the A/C has a large in-rush current when it turns ON....be sure the current rating of the Surge Protector or RFI/EMI Filter is about TEN TIMES the published RUNNING current rating for the A/C.
As my previous comment I ended up putting in an in-line EMI filter on the TV's power cable.

To put one on the air con power do you reverse the EMI filter?? Or does it still go on the same way? Just curious as it would be nice to hit this at the source rather than letting the voltage spikes run through everything else aside from the TV....??
 

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Discussion Starter · #12 ·
Dam it... it was going great for around 4 hours.

The air con compressor just switched OFF and the screen pixelated again...

So I have a UPS, a surge protected power board and an inline AC filter on the TV power and RF shielding on the antenna plugs....

I might try the inline filter on the air con power and see what happens... Can't see it helping tho. If it can't stop the power spike on the TV's power line then it's not going to stop it on the air cone power side.

Its only done it once but if it's done it once it will do it again.

Does not seem to do it when the compressor switches on now, only off... so looks liek the voltage drop is OK its a voltage spike when it switches off which is odd considering all the gear I have on the power line to the TV.
 

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Discussion Starter · #13 ·
You know - this ONLY happens when the television is on live TV via the antenna.

When the TV is on the HDMI channels it does not do this at all.

I'm thinking this is more of an RF antenna interference issue than power again you know..... But I guess it could still be power playing with the in-built tuner I am not sure which.
 

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The A/C is obviously generating RF Interference (EMI) into the TV Band(s).....which can be radiated into the air directly from within the case....or much more efficiently via an attached "Antenna"...i.e. the POWER CORD. The TV is "probably" picking up this EMI via it's Antenna, but conduction via the Power wires can also be an issue. Ideally an EMI Filter should be mounted WITHIN the A/C's case as close as possible to the SOURCE of the EMI.....but when mounted at the END of the A/C's "Antenna" it would also be very effective in SHORTING OUT EMI so it is neither Radiated into the air nor Conducted to the TV via the Power wires.

PS: When the active Magnetic Field in the A/C motor is suddenly switched OFF, it generates a "BACK EMF" that can result in a SPARK jumping across the Switch (or Relay if used) Contacts....this is the SAME mechanism using in automobile Ignition systems....when the Ignition Coil's Magnetic Field is interrupted, a Spark is generated, jumping across each attached Spark Plug. A well-designed A/C would have a Spark Suppressor (probably a Capacitor and Resistor in Series) across it's Power Switch...or Relay if used:
http://en.wikipedia.org/wiki/Arc_suppression
http://www.industrologic.com/mechrela.htm
Note that the Spark Suppressor's Capacitor voltage rating must be several times (e.g. 4x or more) the operating voltage (240 VAC) [Which may require putting multiple (say) 300 VAC Capacitors in SERIES] and the Resistor's power rating must be greater (2x or more) than the amount of power (actually Energy) expected when suppressing the spark...which is presumed to last a certain number of milliseconds (so 1 Watt should be enough).

I don't know the particulars of your particular EMI Filter, but some are symmetric and doesn't matter which way it's connected....and some are more complicated and work a bit BETTER in one direction than the other....depending on whether optimized to protect against EMI ENTERING the device or optimized for protecting against EMI EXITING the device (the usual case):
http://www.digikey.com/Web%20Export/Supplier%20Content/Lambda_285/PDF/TDKLambda_all_about_emi_epmag.pdf?redirected=1
Note that the Common and Differential Mode Noise differences occur at frequencies MUCH LOWER than TV Bands.....where it is effectively Symmetric....so you should be able to use it either way....simply match up the Power Plugs....
 

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Discussion Starter · #15 ·
The A/C is obviously generating RF Interference (EMI) into the TV Band(s).....which can be radiated into the air either directly from within the case....or much more efficiently via an attached "Antenna"...i.e. the POWER CORD. The TV is "probably" picking up this EMI via it's Antenna, but conduction via the Power wires can also be an issue. Ideally an EMI Filter should be mounted WITHIN the A/C's case as close as possible to the SOURCE of the EMI.....but when mounted at the END of the A/C's "Antenna" it would also be very effective in SHORTING OUT EMI so it is neither Radiated into the air nor Conducted to the TV via the Power wires.

PS: When the active Magnetic Field in the A/C motor is suddenly switched OFF, it generates a "BACK EMF" that can result in a SPARK jumping across the Switch (or Relay if used) Contacts....this is the SAME mechanism using in automobile Ignition systems....when the Ignition Coil's Magnetic Field is interrupted, a Spark is generated, jumping across each attached Spark Plug. A well-designed A/C would have a Spark Suppressor (probably a Capacitor and Resistor in Series) across it's Power Switch...or Relay if used:
http://en.wikipedia.org/wiki/Arc_suppression
http://www.industrologic.com/mechrela.htm
Note that the Spark Suppressor's Capacitor voltage rating must be several times (e.g. 4x or more) the operating voltage (240 VAC) [Which may require putting multiple (say) 300 VAC Capacitors in SERIES] and the Resistor's power rating must be greater (2x or more) than the amount of power (actually Energy) expected when suppressing the spark...which is presumed to last a certain number of milliseconds (so 1 Watt should be enough).
But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
 

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But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
The line terminals always go to the AC mains or wall outlet. The load terminals always go to the equipment that is being powered. Make sure the filter is rated to handle the startup current draw of the device being powered.
 

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But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
Highly perceptive of you.

Yes, you need to swap the connectors when you install it in the air conditioner line.

The filter has inductors on the noisy side and capacitors on the quiet side. It definitely matters which way you orient it. When you first installed it, you put the inductors toward the noisy line (toward the AC) and the capacitors toward the quiet line (toward the TV).

You need to keep the same orientation so swap the connectors and plug it in the AC line. If that helps even more, but still is inadequate, then start thinking about building it into the AC chassis at the very end of the power cord.

You could also try clipping a large ferrite bead on the 'noisy' side of the filter to see if that helps reduce the noise even more. If still not working correctly you could try adding one to the TV power cord too if it does not have one already. Finally, you could try adding a third on the 'quiet' side of the filter, or swapping from the 'noisy' to the 'quiet' side.

It seems as if you are on the right track.
 

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Discussion Starter · #18 ·
Just to be clear.... The schematic on this says on one side "line/load" and on the other side "load/line".

Is what your saying, the terminals on the side marked line/load, goto the AC mains wall and the terminals marked load/line goto the equipment?

They don't make things easy on these schematics. I think I already have it back to front I am going to have to pull it apart and double check it now......but I am pretty sure I put the 3 terminal side marked load/line to the mains power wall on the unit I have....

:eek::confused::eek::confused::eek::confused::eek::confused::eek::confused::eek::confused:
 

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Typical EMI Filters do NOT have Capacitors on one side and Inductors on the other [Capacitor are CHEAP...so might as well use them on BOTH sides for better performance at minimal additional cost]. EMI Filters are usually BALANCED Filters with Capacitors on BOTH Input and Output....and Inductors in between them....so it's SYMMETRIC...although there COULD be differences in voltage ratings between "Input" and "Output" Capacitors (although probably NOT) and esp. how the Grounds are connected, as I mentioned above:
https://www.google.com/search?q=emi...B4QsAQ#tbm=isch&q=emi+filter+schematic+images

It might help if you could cite a link to the specs for your particular EMI Filter....

BTW: Line/Load and Load/Line markings clearly indicate that it can be hooked up in EITHER DIRECTION....
 
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