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Debouncing Fails on My Remotes periodically!

Discussion in 'Electronic Repair' started by [email protected], Dec 14, 2013.

  1. Guest

    Really annoying!

    30" Sanyo pureflat CRT TV and JVC DVD/VHS combo remotes. Both have volume on their remotes and can be universally programmed.

    Happens for a few minutes at random times - might happen twice per month, once per week, or twice per year.

    I go to adjust the TV vol with either its native remote or the JVC's, and I press up or down, nothing happens. I press them harder, and the volume will keep going all the way up or all the way down.

    Adjusting the volume via the buttons on the TV itself no problem.

    What is causing the behavior of the two remotes??
     
  2. N_Cook

    N_Cook Guest

    you gave the reason yourself
    " I press them harder"
     
  3. I think it can be summed up in two words: Dirty contacts.

    Open the remote and carefully clean everything. That should end the problem.
     
  4. Guest

    William Sommerwerck:

    The weird thing is that this happens to both remotes at the same exact times and days of the year. In another hour, they will both be fine, and the episode won't repeat for another two weeks to a month.
     
  5. The weird thing is that this happens to both remotes at the same
    Assuming you're reporting this honestly, I can only guess that the problem is
    caused by interference from window or room illumination.
     
  6. Guest

    William Sommerwerck wrote "- show quoted text -
    Assuming you're reporting this honestly, I can only guess that the problem is caused by interference from window or room illumination. "

    I'm not here to jerk anyone's chain. Got enough people in DC doing that to us right now. ;)
     
  7. Guest

    Thing to remember here is that with many IR remote systems, a command like volume has a code, a pulse train of course. However once the micro in the TV or whatever gets the code, ANY continued IR recieved will continue the operation. The remote does not repeat the pulse train, it just puts out bursts of IR at so many millisecond intervals.

    This means that the TV might pick up just any stray IR and think you are still pressing the button.

    Not all systems are like that but since it seems like it would be cheaper to implement, it's likely designed that way.

    Sometimes you can test that theory by taking the right remote and a completely unrelated remote and hitting vol+ for example on the right remote and then hold down any key on the other remote. If the volume keeps going up, that's what you got.

    In that case look for other sources of IR in the room, even sunlight reflecting off something, or in some kinda rare cases CCFL lighting. I know CCFLsare not supposed to put out IR but supposed to is a relative term. There was a thread on that not long ago but in that case apparently the CCFL interfered with the IR. While the IR output may be quite low, the reciever mightbe sensitive enough to take what it's got and misinterpret it.
     
  8. Guest

    UPDATE:

    CFL bulbs on or off have no effect on all remotes debounce fail at once.

    Living room is also away from sunniest portion of house.
     
  9. Guest

    dave:

    I've changed the batteries in all these remotes frequently enough to keep Duracell permanently in the black. LOL! Problem still persists.
     
  10. Jeff Urban

    Jeff Urban Guest

    Then the only answer is the remote reciever.
     
  11. Kaz Kylheku

    Kaz Kylheku Guest

    Since the behavior is reproducible with two completely different remote control
    units from different manufacturers, the problem is probably not with the
    remotes.

    Perhaps there is some source of infra-red pulses in your environment. Is there
    another IR system in use in the room, like an IR based wireless mouse?

    Failing an environmental cause, the next thing to suspect would be the TV
    itself getting into some faulty state state in which it briefly fails to
    respond.

    Specifically, suppose that the embedded system goes briefly unresponsive, but
    continues to handle interrupts from its IR stack and queue up the commands
    in its buffers.

    When you're holding down your remote's keys, you're sending multiple volume-up
    commands. These look like they are being ignored but they are actually
    buffered. When the TV's embedded system comes out of its "guru meditation", it
    processes all of those commands, resulting in the volume going all the way up.

    The solution for you is to relax. When the TV does not respond, back off. Do
    not press the keys harder, and do not hold them down; trust me, these
    controllers are not pressure or velocity sensitive. Just let go of the volume
    key, wait a second or two, and give it just a single tap. If that doesn't work,
    wait a little longer and try again.
     
  12. Guest

    Start unplugging ALL electric/electronic devices in your home, eventually you should find a solution. This includes all lights, ANYTHING that runs onelectyricity. It could be almost anything that plugs into an outlet or runs on batteries. If you know an electromagnetic compatibility engineer (EMC engineer), they might be able to use a spectrum analyzer to find a noise source. But there are only a few thousand of us in the USA so chances are you are on your own to find this problem. The fact that two separate systemsfail simultaneously pretty much says it is not the remotes themselves, butsomething getting into the receivers.
     
  13. Guest

    Jan wrote:
    "Start unplugging ALL electric/electronic devices in your home, eventually you should find a solution. This includes all lights, ANYTHING that runs on electyricity. It could be almost anything that plugs into an outlet or runs on batteries. If you know an electromagnetic compatibility engineer (EMCengineer), they might be able to use a spectrum analyzer to find a noise source. But there are only a few thousand of us in the USA so chances are you are on your own to find this problem. The fact that two separate systems fail simultaneously pretty much says it is not the remotes themselves, but something getting into the receivers. "

    Thanks for this draconian suggestion! Lol.

    See, this problem happens at random, and might recur two weeks apart, or, two months apart. Relatively infrequently.

    The remotes involved are for my 32" Sanyo flat tube TV, and my JVC VHS/DVD combo deck. Both are ten years old but are in fine shape and work flawlessly(aside from this weird remote problem).

    The JVC combo remote can also be programmed for basic on/off, channel, and volume of a television. It is thusly programmed to control those functionsof the Sanyo.

    The typical scenario: I pick up the Sanyo TV remote to adjust the volume, press volume up or down, and nothing happens. I press harder, and the volume just races away - up or or down. I then must run over to the TV and press the volume buttons to stop it.

    Ditto the volume buttons on the JVC remote. And they both behave this way at the SAME time. The episode typically lasts minutes, and in a half-hourboth remotes' volumes operate normally. And it may not happen again for another week or even months.
     
  14. N_Cook

    N_Cook Guest

    Assuming its a neighbour with remote controlled house lighting or
    something like that , coding on the mains getting to the room lights.
    Try temporary spots sloppy-gluing a tube shroud over the sensor of the
    units and direct the axis(by cutting an angle to the glue face) of the
    shroud to where you usually use the remote (assuming not in line with a
    room light of course)
     
  15. Guest

    I say it's the remote recieve in the TV. It's getting noisy. If it isn't that it's the microprocessor.
     
  16. Guest

    Kaz Kylheku wrote: "When you're holding down your remote's keys, you're sending multiple volume-up "

    I must apologize for not being clear by "pressing harder". What I meant was I press the button with more FORCE, not for a longer duration.

    Pressing the volume up/down once(the equivalent of a keystroke on a keybd) should adjust the volume by one value up or down.

    I keep pressing it until my finger bone feels like it will either break or go through the back of the remote - THEN the volume races away like an NHRA hotrod - all the way up or down.

    When I attempt to adjust the volume on the other remote, this phenomenon repeats.
     
  17. I'm thinking... Maybe you just have dirty remote controls.
     
  18. Guest

    ****. You ever work on TVs folks ? If I hemmed and hawed about it like this I would be making donuts.

    You got a choice. Put a scope on the output of the IR sensor and wait days or weeks for the problem to occur, or replace the $1.50 sensor and see if it works. If the problem persists replace the micro if possible, or the main board.
     
  19. If the remote was really that important and maybe not replaceable, you
    could put a CMOS version of a 555 timer on the output LED driver that
    would have a timeOn delay and TimeOff delay to snub the output so that
    only one frame gets sent.

    Jamie
     
  20. Guest

    OK, I don't know what is wrong here but let's just explore some logic here eh ?

    Two, that is two (2) remotes, one OEM and one universal, are doing the sameexact thing. One is OEM and one is universal therefore they are different chipsets and the odds against them having the exact same symptom, an INTEMITTENT symptom that occurs at the same time in both remotes, that have different chipsets, is astronomical.

    We have gone though just about everything in the house. The CFLs, the sunlight, all that.

    Oh shit.

    Hey OP, you still around ? The last, very last test - when this happens again, BLOCK the IR sensor window and see if it stops. If it keeps going then it is for sure either the IR sensor or the micro in the TV. If you've already done that, disregard. We went through all the possible sources that you know about, but IR is not visible to the naked eye, so there is still a possibility.

    Literally, stick your thumb over the window. That is the LAST definitive test.

    IF it DOES stop with your thumb over the window, ummm, do you have an alarmsystem in the house ? Possibly with motion detectors ?

    That is the ONLY other thing it could be other than the TV. Because the twoDIFFERENT remotes act up at exactly the same time, they are RULED OUT AS APOSSIBLITY by LOGIC.

    If you do not have motion detectors (even near a window from outside), if you are sure there is no source of IR hitting that thing, it is the detectoror the micro. No doubt.

    Now the sticky part, hahaha. you see I was always the one to do these wierdproblems of course....

    The reason you must stick your thumb over the window on the TV is because (now get this lol), your neighbor could have a motion detector light outside.. The IR could be bouncing off of someting out there and into your window. Literally, it could be occurring when he parks his car just about a couple of cm. over to the right (or left) of normal, and you would NEVER know it. Remember you cannot see IR.

    The odds of this are not great, it is quite unlikely, but it is possible. Ihave had shit like this. I have had vertical height screwing up the greyscale (because the worng dud was used in the reman of a CRT), I have had an unexplainable ground loop through a cable box that caused a hum bar in a projector because there were two ground rods installed at the house. I have had some pretty wierd problems and I know how to solve them. You have to consider the impossible sometimes.

    This is your last test. Next you replace the IR sensor in the tv, and I give it a 50/50 chance. It could just as likely be the micro. If that's the case it is probably an SMD and is either difficult to replace or maybe near impossible, which would mean a new signal/main board.
     
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