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Interesting Power issue

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by Doug Brott, Nov 28, 2007.

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  1. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    I have added a second HR20 to my bedroom. It is currently a temporary situation, but will likely stay this way for another 6 months or so.

    The interesting thing is that since I added this second system I have a very odd problem. On one of the HR20s, the remote control stops working when the television is turned on. Both systems are in IR mode and the same HR20 has problems. Obviously it complicates changing the channel or using the menus when the remote control does not work. If I turn the TV off, the remote control starts working again.

    Does anyone know why I may be seeing this? I was going to put a meter on the power source but I can't find my meter right now :lol:. Other than perhaps poor voltage control, I was wondering if anyone had thoughts.

    The two HR20s are stacked (just like in the family room) and the TV is about 6-12 inches away (corner of TV to back corner of HR20 stack) with the HR20s just below the bottom of the TVs.

    I have my workaround, but this seems very bizarre to me.
     
  2. Earl Bonovich

    Earl Bonovich Lifetime Achiever

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    There is a problem, where some HR20's get just enough IR interfearence from neary by TV display units.

    Try sliding your HR20's back a bit, so that there is a barier between them and the TV display.

    Or just to test the theory, a piece of cardboard next to the HR20's to block the TV screen picture to the IR sensor.
     
  3. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    Thats a thought .. I'll give it a try.
     
  4. Lee L

    Lee L Hall Of Fame

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    Well, it says you have HR20-700s and the RF actualy works on those and you surely know about it so why not use that?

    What kind of TV do you have? Plasma and LCDs are much worse for this than other types. I have a remote IR setup and had to buy a different IR receiver when we added an LCD.
     
  5. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    The TV is a 26" LCD .. I'll try the "shield" first and see if it makes a difference. If it does, then I'll have to play around with the stack to find a working solution. I'll check out RF as well, but it's funny trying to switch modes when I can't use the remote :). I'll let you know my results later tonight.
     
  6. d0ug

    d0ug Legend

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    I have read that IR can be a problem with plasma sets. It sounds like it is EMI created by the high voltages in the actual plasma panel. The EMI gets inducted into the IR detector circuitry on poorly designed IR detectors. This was a problem with the newer HD Tivo units.

    Never herd of it with LCDs, but I suppose the high voltage inverters for the CCFL bulbs could be radiating some kind of EMI.
     
  7. LarryFlowers

    LarryFlowers New Member

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    Doug... you're not alone!!

    My new Samsung 4665 LCD does this to me every day. When I wake, I turn it on and go for the coffee, in about 10 minutes I will be able to use the remote without further problems.

    I tried shielding the sensor, didnt work, and I can't move the unit due to space limitations. My H20-100 is in same place and is on RF and works fine so I usually use it at first then switch to the HR

    Its very annoying!:nono2:
     
  8. d0ug

    d0ug Legend

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    Fortunately I am not having this problem, I have only read about it.

    Since this seems to be an EMI issue, shielding the sensor with cardboard or something similar to block light isn't going to help. You need something that can block radio frequencies. The easiest solution for EMI interference is to just increase the distance between the device being affected by the EMI and the device creating the EMI. Or put your DVR in a faraday cage.
     
  9. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    I might try some tin-foil formed in the shape of the DIRECTV logo :p

    Distance will be my first try, but I am space limited to some degree.
     
  10. d0ug

    d0ug Legend

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    I not any kind of RF engineer or anything, so I am not 100% positive this will work, but you may be able to try shielding your shelf.

    I don’t know what kind of setup you have your TV on, but if it is one of those typical TV stands with the shelves underneath, you could try putting a layer of aluminum foil on the bottom side of the shelf that the TV is sitting on. If you do a good job taping it up there, most likely no one will be able to see it is there, then run a simple grounding wire from the aluminum foil to the screw holding on an outlet cover. This should ground the entire foil "shield" and hopefully absorb some of your EMI

    If anything it costs you nothing but time to try.

    I seem to remember reading about people doing this when they would run dual CRT monitors next to each other. The EMI from the monitors would cause noise and distortions in the adjacent monitors sometimes. People would cut a piece of cardboard large enough to isolate the 2 monitors, wrap it in foil, ground it with a simple wire going to the outlet screw, and then place it between the monitors.
     
  11. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    Well, the TV is hanging on the wall .. Turns out that by adjusting the brightness and contrast level, I was able to minimize the effect. I never moved the equipment. I still get no response from the HR20 just as the TV is powered on, but within seconds it starts working again.

    I think in the past maybe after 20 minutes it would start working a little, but more recently I've never been patient enough to verify that fact.

    Moral of the story .. lower the contrast & brightness if there is a problem.

    As an aside, a sweatshirt placed over the front (glass portion) of the LCD actually provided enough shielding. Sweat shirt on .. remote works .. sweat shirt off .. remote fails. It was quite funny if I wasn't really trying to solve a problem.
     
  12. d0ug

    d0ug Legend

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    Hmm interesting about the sweater, sounds like it might have something to do with the light coming off the panel. I doubt a sweater is going to do much to block EMI, unless its woven out of steel wool =P
     
  13. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Had this with my "new" Sony [see sig]. Lost the MCE 2005 IR remote senor.
    Changing the "power saving" options on the Sony would "fix it". I ended up changing the location of the IR sensor instead.
    Use RF mode for my D* stuff.
     
  14. houskamp

    houskamp Active Member

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    That was my thought too..
    have you tried putting black tape over the IR sensor? maybe the reciever is somehow still breifly looking at the IR during power on?
     
  15. Lee L

    Lee L Hall Of Fame

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    When I had the issue, I also noticed that it got better after a few minutes. I guess the backlight in the LCD must give off extra IR until it is fully warmed up.

    I see your point about switching to RF being difficult as you do need to read the numbers off the screen to to it.
     
  16. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    But you could to it the "old school" way:
    Use the front panel to navigate to the instruction screen, then write them down, turn off the TV and go through the steps to change to RF. Once the receiver starts too blink [responding to remote] then you can turn the TV back on.
     
  17. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    Or I could cover it with my sweat shirt :lol:

    Yeah, I definitely reduced the backlight and that may have been the real solution .. It's funny that it only affected one of the receivers. I was probably at just the "wrong" distance away based on the frequency of the light. Reducing the backlight probably changed the frequency just enough to make a difference.
     
  18. armophob

    armophob Difficulty Concen........

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    A tin foil hat may help as well.:)
     
  19. mertzf

    mertzf Mentor

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    My thoughts: the LCD TV is emitting IR as it turns on. Case in point: my MBR TV is FLAT on the wall, facing the bed. On the wall opposite to the TV, there is a picture frame, with a glass front, pretty much parallel to the TV. In order to make the old Tivo work from the closet (no line of sight), I bought an Radio Shack IR repeater (captures the IR from the remote, and repeats it in the closet). I noticed that every time I turn the TV on, the capture part of the repeater lights up like crazy, as if I kept pushing on a remote button. It usually goes away in a few seconds.

    In your case, I would try to diminish the TV IR from feeding back into the receiver IR sensor. Maybe you have glass the IR could bounce off of. Maybe you want to put your TV at more of an angle on the wall (tilting mount). Also, you may want to try putting the sweater on things around the room that could reflect the IR (picture frame, furniture, you get the idea...) to identify the source of the reflection. Best of luck.
     
  20. Lee L

    Lee L Hall Of Fame

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    I noticed the same thing with my IR repeater - the talkback light was lit like crazy. However, even with it mounted on the back of hte TV and facing up toward the ceiling and hte TV angled slightly down for optimal veiwing, enough IR hit it to mess it up, until I changed to a CFL friendly IR receiver.

    As far as one being a problem, it could also be that part or installation tolerances cause one to be more suceptible than the other.
     
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