Why does my satellite remote control now longer work with my new HDTV?

March 25, 2009 4:15 PM

I recently purchased a new HDTV and all of a sudden I'm having a lot of problems with my satellite remote no longer working.

So I purchased a new Toshiba HDTV last week (46XV545U) and it finally arrived yesterday. After setting the TV up I noticed that my Dish Network cable box (VIP211) would just no longer receive/accept IR signals from the remote if it was more than three inches from the front of the cable box. I've never had this problem before, and I've had the cable box for around 3 years.

I also happen to have an HTPC connected to the TV with a Microsoft wireless IR keyboard, and that comes with a little IR USB receiver. I know that whenever an IR signal is emitted a little light on the front of the unit will light up. I've now noticed that whenever I turn the TV on the light on the IR receiver is constantly on, meaning that something is sending IR signals its way. As soon as I shut the TV off, the light turns off on the IR receiver. Does anyone have any idea what would cause the TV to emit IR signals constantly when turned on? I haven't yet contacted Toshiba or Dish Network because I'm trying to fix it myself without decending into help-desk hell.

posted by SweetJesus to technology (9 comments total)

Plasmas and LCDs are notorious for generating this sort of IR interference. You need to get your cable box farther from the TV, and ideally with a partition of some sort (a shelf, the side of a cabinet, an old cardboard box folded into a shield) blocking the line of sight from the cable box to the TV.

Some companies, Xantech being one of them, manufacture "plasma-proof" IR receiver/repeater systems that will allow you to hide the cable box and any other IR-operated gear behind a closed cabinet door.

Depending on the manufacturer of the sat box, it may have a remote with an RF option which will also take care of the problem, though you're likely to experience the same issues wit any dvd player/surround receiver/etc you stick in the same spot.

God, I hate IR.
posted by contraption at 5:41 PM on March 25

Do you have a digital camera? Usually if you look through the viewfinder you can see the IR emitted from a remote control, maybe you can also spot this source?
posted by defcom1 at 5:43 PM on March 25

'doh. Should have used preview.
posted by defcom1 at 5:45 PM on March 25

That camera trick is a great one, defcom1, and I use it all the time to troubleshoot IR systems with my cellphone camera (actually it's about the only thing my phonecam is good for.) In this case, though, since the TV is also emitting visible light it'd be hard to distinguish the IR, though the image may appear brighter than it "should" when viewed through the camera.

It's an awesome trick though, and I'm glad you brought it up.
posted by contraption at 5:59 PM on March 25

I suppose it doesn't help that I have a glass TV table that was originally purchased for a larger TV and has got a lot of extra room on it...

I spent a good amount of time trying things out, and unfortunately none of the suggestions worked. I tried to digital camera tick with my cell phone, which was really neat, but there was too much light emitting from the tv to be able to tell if there was any actual specific IR source. I tried to partition off the glass with books but that didn't seem to work either - the IR receiver I have stays lit up until I literally cover it with my hand when it is anywhere near the tv. I even put a large metal computer case over the IR receiver and it was still lit up. So for whatever reason my living room has a lot of IR activity. I even attempted to change the frequency my remote operates on (who knew you could even do that, but apparently you can with Dish Network..) but every one of the frequencies didn't work.

But I did find a solution that works! It suggested figuring out which IR ports on the cable box was receiving and which was transmitting, and then covering up the transmitting IR port with a piece of tape. That works perfectly. I'm a fairly technical person but that seems like black magic to me. Why would my Dish Network cable box be transmitting an IR signal? And why would blocking it allow my remote to work?
posted by SweetJesus at 9:13 PM on March 25

Glad you got it working! I'm not familiar with that particular model of DVR, but I'd be very surprised if there was an IR transmitter on the front of the box. My guess would be that the tape attenuates the background IR enough that the IR receiver is no longer saturated by the noise from the TV and can now pick out the slightly stronger signals coming from the remote.

When you say you figured out which port was transmitting, do you mean you used the camera method and actually saw the led lighting up, or did you just try tape in one spot and then another?
posted by contraption at 9:37 PM on March 25

I'm not familiar with that particular model of DVR, but I'd be very surprised if there was an IR transmitter on the front of the box.

Yeah, that was my inital reaction as well. What use would a IR transmitter be to a cable box? I'm thinking the person who originally suggested the tape idea was mistaken about there being an IR transmitter. Just to confirm I took a look using the camera technique and I didn't see any lights out of the IR ports.

When you say you figured out which port was transmitting, do you mean you used the camera method and actually saw the led lighting up, or did you just try tape in one spot and then another?

There are three small, black cirlces on the front of the unit that I identify to be possible IR ports (pic). When I cover up the left most two and leave the right one open, the remote works. I'm not actually using tape either, I just bent an envelope around to cover the ports. I'm moving in a month and getting FIOS anyway, so this a perfect fix for the time being.

Thanks for your help.
posted by SweetJesus at 10:35 PM on March 25

Oh, and this problem seems to me to be completely isolated to the Dish Network box. My Sony amp and dvd player works fine with either their OEM remotes or the crappy universal remote I've got lying around. There must be something in particular about the frequency the dish network box is using for the remote that's screwing things up, but I tried all 15 different frequency options and got nowhere...
posted by SweetJesus at 10:45 PM on March 25

It probably has more to do with the quality of the IR receiver and filter on the Dish box than frequency; IR remotes are standardized at 36 kHz, which is what allows universal remotes to work. When a remote has multiple "frequencies" available, generally what's changing is not the actual carrier frequency, but a preamble that gets sent before each command so that only boxes set to the corresponding ID will pay attention. This is useful when you have more than one box in close proximity and want to ensure that the commands you're sending only control one of them.
posted by contraption at 1:10 AM on March 26