# IR interference from LCD TV...



## Greg Alsobrook

I just had my plasma swapped out under warranty the other day for a new LCD... and the IR interference is _terrible_... It's totally killing the signal to my HR20... I literally have to try for 2-3 minutes to get one command to it...

I'm using a Harmony 880 right now, but have tried the DirecTV remote as well with no luck...

Any suggestions? Would it help if I switched to the other IR frequency? If so, does anyone know how to do that with a Harmony?

TIA...


----------



## gulfwarvet

AirRocker said:


> I just had my plasma swapped out under warranty the other day for a new LCD... and the IR interference is _terrible_... It's totally killing the signal to my HR20... I literally have to try for 2-3 minutes to get one command to it...
> 
> I'm using a Harmony 880 right now, but have tried the DirecTV remote as well with no luck...
> 
> Any suggestions? Would it help if I switched to the other IR frequency? If so, does anyone know how to do that with a Harmony?
> 
> TIA...


sorry to here whats going one AR, i have no clue to help.

but maybe some info about the make and model of the LCD might help others tend to your needs?


----------



## davring

I wish I could offer some help. I, and a couple of other family members have a few of the KDL series Bravia's with no interference trouble at all.


----------



## Carl Spock

Distance is the only cure. Signal interference falls off at the square of the distance. In other words, if your DVR is a foot away from the TV now, and you can move it to two feet away, the interference will be a quarter of the strength. Move it four feet away and you'll have a sixteenth of the interference.


----------



## harsh

You're not going to like it, but the best solution is to go RF.

Sounds like you might consider turning the brightness down to somewhere below the "retina, well" level.

The problem with IR is that it is one wavelength regardless of the remote code set.

It may be possible to fashion some sort of "feed horn" around the IR detector on the HR20. Make sure the TV isn't reflecting off of something and casting a ray of IR on the DVR.


----------



## Carl Spock

harsh is right. I believe it is the IR carrier frequency that is being interfered with, and that's the same for all codes.


----------



## tcusta00

I recall reading about the problem here before and the solution that someone found, IIRC, was to turn down the brightness on the TV... if possible.


----------



## houskamp

move the DVR.. even slightly.. just need to reduce the line of site from the screen..


----------



## Carl Spock

I'm not sure this is a line of sight issue. I think it's a radiation issue. I've had interference problems with LCD TVs even when they couldn't "see" the components. They were just too close.


----------



## houskamp

Carl Spock said:


> I'm not sure this is a line of sight issue. I think it's a radiation issue. I've had interference problems with LCD TVs even when they couldn't "see" the components. They were just too close.


mine had the problem, just turning the DVR fixed it 99.9% (still won't respond for 10 seconds on powerup).. It's 6' away..


----------



## Greg Alsobrook

harsh said:


> You're not going to like it, but the best solution is to go RF.
> 
> Sounds like you might consider turning the brightness down to somewhere below the "retina, well" level.
> 
> The problem with IR is that it is one wavelength regardless of the remote code set.
> 
> It may be possible to fashion some sort of "feed horn" around the IR detector on the HR20. Make sure the TV isn't reflecting off of something and casting a ray of IR on the DVR.


Thanks for the info harsh... And thanks for the tips everyone...

Here's a little more info...

The TV is a KDL-37XBR6. The DVR is in a cabinet and the TV sits on top... Here is a pic (with the old plasma)... http://www.dbstalk.com/attachment.php?attachmentid=14478&d=1215281053

I don't really have the option of moving it 'feet' away with this setup...

I have tried opening the glass thinking that maybe it was reflecting something back onto the IR lens... but it doesn't seem to matter whether the glass is open or not...

The TV has some sort of auto dimming feature (which is really cool by the way)... it responds to ambient light, and adjusts the brightness accordingly... so at night, when the lights are out in the room, the brightness is already about as low as I would want to take it... And, strangely enough, that's when I seem to have the most issues... It doesn't really seem to be as bad during the day...

Also, I read somewhere that it can improve after the TV has been on for a while... which does seem to hold some truth...

FWIW, it's working fine right now with the lights on in the room and the brightness level pretty high... But the past three nights, it's been atrocious... Even after the TV has been on for a good while.. (30-45 min. +)

As Smoke suggested, I will try moving it forward and backward some in the cabinet to see if that helps at all... If that doesn't work, I guess I may have to buy an 890... since I'm using a Harmony 880, RF isn't an option...

Thanks again everyone...


----------



## Grentz

Interesting, most of my experiences with this have come from Plasma sets, not LCDs.

It really is a model by model basis though. As others have suggested, turning down the brightness and better location of the IR receiver are the main things that can help.

The Harmony 890 is also a good option to overcome the issue.


----------



## RobertE

If possible, try to disable the auto dimming.


----------



## Greg Alsobrook

RobertE said:


> If possible, try to disable the auto dimming.


Why? I like it... :grin:


----------



## Jason Nipp

Wow, IR interference is a common phenomena of Plasmas..... Have rarely ever seen an LCD cause this.

The HR's IR wavelength must be really low.

I would kill the auto dimming as Robert suggested.

So Air.... What did you end up getting?


----------



## davring

AirRocker said:


> Why? I like it... :grin:


The auto brightness is a cool feature, my set is in our Florida(family) room which mostly glass, so the room light changes like night and day, and the brightness on the screen is always comfortable. I couldn't see how turning the auto feature off would help, although it does control the backlight which is florescent. Hope you figure it out.


----------



## Jason Nipp

Grentz said:


> Interesting, most of my experiences with this have come from Plasma sets, not LCDs.
> 
> It really is a model by model basis though. As others have suggested, turning down the brightness and better location of the IR receiver are the main things that can help.
> 
> The Harmony 890 is also a good option to overcome the issue.


----------



## Grentz

Note that Auto backlight does not always mean it is changing brightness based on the room light level. Many times on LCDs auto backlight is actually automatic based on input content as I found out with my Samsung LCD. It dynamically adjusts the backlight to proper suit the input picture and has nothing to do with the actual room brightness.

One way to find this out is to see if your TV actually has a brightness sensor, if it does that usually means it is controlling auto brightness off of the room it is in, if it does not it usually means auto brightness is referring to brightness control based on input content.



Jason Nipp said:


>


The picture is not showing for me


----------



## davring

If I take a samll flashlight and shine it near the the pilot light(botton corner) rhe screen brightens immediately. The LCD's that adjust the backlight based on the scene content are the newest sets with LED powered backlights, I beleive.


----------



## Grentz

davring said:


> If I take a samll flashlight and shine it near the the pilot light(botton corner) rhe screen brightens immediately. The LCD's that adjust the backlight based on the scene content are the newest sets with LED powered backlights, I beleive.


Yup, you have a brightness sensor then and nope it's not just newer ones or ones with LED backlights, mine has the standard CCFL backlight.

In any case, I would rather have one with a true brightness sensor so you are lucky! I have a very bright living room and it would be nice to have it auto adjust, the content based adjustment I have found to be pretty worthless in actual use so I turned it off after a few weeks.


----------



## Jason Nipp

Grentz said:


> =The picture is not showing for me


It's a smiley holding a +1 sign.


----------



## Greg Alsobrook

Grentz said:


> Note that Auto backlight does not always mean it is changing brightness based on the room light level.


There is a setting in the Menu called "Light Sensor"... and its description is "Optimizes brightness according to ambient light"...

And it definitely does just that... I have a dimmer on the lights in the bedroom, and if I spin it all the way up, the display brightens within seconds... and vice-versa...

So why would disabling this help me? The problem is when the display _is_ dimmed down... And yet, dimming it is supposed to help??


----------



## Grentz

Jason Nipp said:


> It's a smiley holding a +1 sign.


ahh, gotcha 



AirRocker said:


> There is a setting in the Menu called "Light Sensor"... and its description is "Optimizes brightness according to ambient light"...
> 
> And it definitely does just that... I have a dimmer on the lights in the bedroom, and if I spin it all the way up, the display brightens within seconds... and vice-versa...
> 
> So why would disabling this help me? The problem is when the display _is_ dimmed down? And yet, dimming it is supposed to help...


Ya, that is weird. Usually dimming the backlight helps as it supposedly emits less IR then because there is less light output.

But like I said, my experience is with Plasmas and this problem, never really seen it as a serious issue from a LCD.


----------



## Greg Alsobrook

Ok... Did some more troubleshooting...

When the lights are all the way up, and the display is bright, it's not so bad... It is much worse when the lights are off (or low), and the display is dimmed down... 

So... I turned off the "Light Sensor" feature... which returned the display to normal (factory setting) brightness... and it did indeed fix the issue.... no matter if the lights in the room are up or down... 

How strange... I guess the frequency that the fluorescent light is emitting when dimmed is totally killing the IR... :scratchin

Well, that's disappointing... I really liked that feature... Guess I may have to switch to RF after all... but at least it's working in the mean-time...

Thanks again all!!


----------



## Grentz

Glad you figured out something that works, not ideal, but works.

Many plasma owners were/are stuck with just having IR issues for everything no matter what they do!


----------



## Greg Alsobrook

Grentz said:


> Glad you figured out something that works, not ideal, but works.
> 
> Many plasma owners were/are stuck with just having IR issues for everything no matter what they do!


Thanks... I'm glad it's fixed as well... It was very aggravating...

Never had a single issue like this with my plasma...


----------



## Grentz

Like I said before, it really is on a model by model basis. Some are great, others are horrible, and even more are in between.


----------



## harsh

AirRocker said:


> If that doesn't work, I guess I may have to buy an 890... since I'm using a Harmony 880, RF isn't an option...


The Harmony 890 still controls the devices through and IR transmitter. It does not send RF signals that an RF remote enabled device would recognize.


----------



## Jason Nipp

AirRocker said:


> So... I turned off the "Light Sensor" feature... which returned the display to normal (factory setting) brightness... and it did indeed fix the issue.... no matter if the lights in the room are up or down...
> 
> How strange... I guess the frequency that the fluorescent light is emitting when dimmed is totally killing the IR... :scratchin


I wish I could post the details of how the light sensor works.... the methodology it self would give a good enough understanding.... But if I did this I would break an NDA.


----------



## davring

Jason Nipp said:


> I wish I could post the details of how the light sensor works.... the methodology it self would give a good enough understanding.... But if I did this I would break an NDA.


I always assumed it was a simple photo cell circuit. I can't imagine it being a very complicated operation. Of course I reserve the right to be very wrong


----------



## LarryFlowers

AirRocker said:


> Thanks... I'm glad it's fixed as well... It was very aggravating...
> 
> Never had a single issue like this with my plasma...


You could try using an offset IR repeater, like they use to relay IR commands to closed home theater closets. They aren't expensive and you could offset it enough to avoid the problem.


----------



## RobertE

AirRocker said:


> Why? I like it... :grin:


Because as you found out, it will "fix" it.



AirRocker said:


> There is a setting in the Menu called "Light Sensor"... and its description is "Optimizes brightness according to ambient light"...
> 
> And it definitely does just that... I have a dimmer on the lights in the bedroom, and if I spin it all the way up, the display brightens within seconds... and vice-versa...
> 
> So why would disabling this help me? The problem is when the display _is_ dimmed down... And yet, dimming it is supposed to help??





AirRocker said:


> Ok... Did some more troubleshooting...
> 
> When the lights are all the way up, and the display is bright, it's not so bad... It is much worse when the lights are off (or low), and the display is dimmed down...
> 
> So... I turned off the "Light Sensor" feature... which returned the display to normal (factory setting) brightness... and it did indeed fix the issue.... no matter if the lights in the room are up or down...
> 
> How strange... I guess the frequency that the fluorescent light is emitting when dimmed is totally killing the IR... :scratchin
> 
> Well, that's disappointing... I really liked that feature... Guess I may have to switch to RF after all... but at least it's working in the mean-time...
> 
> Thanks again all!!


From my understanding it's not the auto dimming feature per se that causes the problem. It's a specific level of brightness/backlighting that causes the issue. For whatever reason at certain levels, the backlight puts out enough IR garbage that it causes havoc with the IR remote/remote sensor. How and why I have no clue, but thats whats been passed on to me by some guys that to extreme high end HT setups.


----------



## Fab55

So here's a dilemma. I'm having the same exact issue with my DirecTV remote not working in IR at certain times. I have a Hitachi 47" LCD, model L47V651. 

It doesn't have an auto-dimming feature, but I do have it set up to go into "Nighttime" mode from 10pm - 6am. Funny, the IR remote doesn't work at all during that time frame. In the morning, when the TV goes back to "Daytime" brightness, the IR works fine. 

My only complaint with the RF function of the remote is that it's very sensitive. Double-keying happens quite frequently. 

Does anyone think it's the exact same issue? I guess the more that I read through the posts, it probably is. Weird, huh?


----------



## Fab55

Sorry, forgot to mention, running an HR20-700 receiver.


----------



## RobertE

Fab55 said:


> So here's a dilemma. I'm having the same exact issue with my DirecTV remote not working in IR at certain times. I have a Hitachi 47" LCD, model L47V651.
> 
> It doesn't have an auto-dimming feature, but I do have it set up to go into "Nighttime" mode from 10pm - 6am. Funny, the IR remote doesn't work at all during that time frame. In the morning, when the TV goes back to "Daytime" brightness, the IR works fine.
> 
> My only complaint with the RF function of the remote is that it's very sensitive. Double-keying happens quite frequently.
> 
> *Does anyone think it's the exact same issue?* I guess the more that I read through the posts, it probably is. Weird, huh?


Yes


----------



## Fab55

Figured as much. Thank you!!!


----------



## Greg Alsobrook

This has started up again out of nowhere... No settings have changed... Nothing in the room has changed... Same remote... etc. Sometimes it takes 5 or 6 presses to get the HR20 to accept one command. With the TV off, it works fine....

I'm at a loss this time...


----------



## racermd

AirRocker said:


> This has started up again out of nowhere... No settings have changed... Nothing in the room has changed... Same remote... etc. Sometimes it takes 5 or 6 presses to get the HR20 to accept one command. With the TV off, it works fine....
> 
> I'm at a loss this time...


I had a very similar problem with my HR20 and a 32" Sharp Aquos LCD. Remote would work fine for a few minutes after starting up the TV, then it would be completely non-responsive for about 30 minutes. After that, it would start working again and be fine for the rest of the time I would watch anything.

I figured out something in the LCD was causing the IR interference because the problem went away if I moved the remote right up to the HR20's IR port. Moved back and the problem returned. Turned the TV off and the problem went away again. Turned the TV back on and the problem returned.

What I found that helped a bit is to change the angle of the TV slightly or moving the HR20 to the left or right a bit.

Assuming that you want to continue using IR instead of switching to RF mode and without putting an IR filter membrane over the entire face of the LCD (or plasma, as others might experience), I don't think there is any permanent solution to this behavior.


----------



## Yoda-DBSguy

Grentz said:


> Glad you figured out something that works, not ideal, but works.
> 
> Many plasma owners were/are stuck with just having IR issues for everything no matter what they do!


Don't say no matter what; as their are solutions that indeed work.

One such solution is to use an IR system such as xantech. They make several models of the target sensor that are plasma/lcd friendly which eliminate the problems altogether.

However without purchasing one of the above or moving the equipment; yes some are still plagued by their own doing.


----------



## rudeney

Except for the newer models using LED backlighting, most LCD's use various forms of "fluorescent" bulbs. These cannot be dimmed simply by reducing the voltage as with incandescent bulbs. When dimmed, the frequency of the light output changes and that can interfere with IR sensors. The best solution is not to dim fluorescent bulbs.


----------



## steve053

AirRocker said:


> This has started up again out of nowhere... No settings have changed... Nothing in the room has changed... Same remote... etc. Sometimes it takes 5 or 6 presses to get the HR20 to accept one command. With the TV off, it works fine....
> 
> I'm at a loss this time...


I feel your pain. The IR in my HR20-100 wigged out in Feb 2008 and it took me 2+ months of fiddeling around to get it stable again. I ended up moving the HR into a cabinet and setting up an IR repeater (hotlink pro).

Just like you everything would work fine for a while, then blam - no IR response from the HR. At times it would 'unlock' after a few seconds, and sometimes it would lock up for several minutes. I could always use the front panel to navigate so I knew it was related to the IR.

I tried the route of black tape and pin holes, but it just never worked consistantly. The only thing that worked was moving it into a cabinet. I tried the xantech system, but ultimately chose hotlink as it was much cheaper and worked as advertised. Both are good choices for ir repeaters.

Best of luck in getting this sorted out.


----------

