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Bizarre TV project/question

Discussion in 'Electronic Repair' started by [email protected], Apr 2, 2006.

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  1. Guest

    I am currently converting an old sit-down racing arcade game into a
    dedicated xbox racing game. I know that probably sounds funny.
    Basically what I have is this...I purchased an old arcade driving
    cabinet that was gutted. (the original arcade monitor and controlling
    circuit board were not in it. The rest of the cabinet was in decent
    shape) I refurbished the cabinet and bought a 27" television from
    walmart and then took the television out of its plastic casing. I then
    modified some brackets and attached them to the television chassis and
    installed it into my arcade driving cabinet. It is a perfect fit and
    should do the job nicely for what I want. It has rca jacks on the
    circuit board for hooking up the xbox to it, so that will also be a
    quick job. My current dilemma is that the television's circuit board
    has a IR sensor on it so you can operate the television with the remote
    controller. Since I installed this tv into another cabinet, I will be
    unable to use the remote control since the circuit board is kind of
    hidden inside the arcade cabinet now. My question is if it is possible
    to desolder the remote sensor off of the circuit board and mount it
    somewhere else on the arcade cabinet and just run wires back to the
    circuit board? I know that this probably sounds insane, but I need to
    have the remote working as I don't think it is possible to get the tv
    to switch to AV mode any other way. Any and all help is welcome and
    appreciated. I can provide pictures if my explanation isn't clear
    enough. Thanks.
     
  2. James Sweet

    James Sweet Guest


    Sure, it's easily done. Do be careful though, the TV may be of the hot
    chassis design, in which case your remote sensor is floating at line
    voltage rather than being grounded so if in doubt, insulate it.
     
  3. Guest

    uuhhh...in english? Sorry, I'm not sure I understand. Are you saying
    that to put the sensor somewhere else on the cabinet I might run the
    risk of getting zapped if I touch it? If so, what exactly should I do
    to avoid arc welding my fingers together?
     
  4. inty's world

    inty's world Guest

    turn off the tv set, desolder the ir reicever.
    take three wires from the PCB (where the three pins of the reicever
    were before you undsoldered it) and connect them to the legs of the
    reicever (1-> 1, 2-> 2, 3-> 3)...
    it's not too insane.. it's insane the xbox-racing-driver :-D
     
  5. Guest

    ok, I guess I follow you. Just so I'm on the same page though...there
    are a total of 5 solder points. I'm thinking that the two on the
    outside are actually holding the IR sensor to the pcb and the three in
    the middle are the brains of the unit??? Right?
     
  6. Arfa Daily

    Arfa Daily Guest

    As James said, moving the remote sensor is not a problem. However, I would
    recommend two additional caveats. First, use single screen twin ( like
    balanced mic cable ) to make the connection, using the screen ( shield ) for
    the ground connection, and one each of the two inners for the +5v supply
    pin, and the data out pin. Second, I would recommend that wherever you mount
    it, you make sure that it's still behind a piece of IR filter material to
    avoid interference from sunlight etc.( there's also no issue then about you
    being able to touch anything ).

    Bart's suggestion above is also a very good one, if you only need to go over
    to AV, and don't need to get access to other remotely controlled functions.

    Arfa
     
  7. inty's world

    inty's world Guest

    uhm..... if you only want to switch AV follow what "bart bervoets"
    said...
    or, if you want to use the remote controller..
    how much pin does the ir reicever have?
     
  8. Guest

    I think that my best bet is to move the remote sensor elsewhere on the
    cabinet as I would like to access all of the remote functions if
    needed. It appears that the pins on the sensor are about 3/16" in
    length. Soldering should be a little tricky, but not impossible.
    Regarding what "Arfa" wrote, I am not sure what you are talking about
    with the single screen shield? What is it? What is balanced mic
    cable? Where can I purchase it? I thought that I could just use some
    telephone wire to extend the sensor out away from the circuit board? I
    appreciate all of the help guys, but I need alot of layman's
    terminology. (I am a fireman by trade, not even remotely an
    electrician or circuit board tech) If you guys could steer me towards
    exactly what type of wire to use and where to purchase it (radio
    shack???) that would help. Also, where can I get IR filter material?
    I tossed out the old tv cabinet a long time ago, so I can't use the old
    IR filter off of that.
     
  9. I.F.

    I.F. Guest

    If the TV has a live chassis there is another option worth considering -
    some retailers sell IRRC remote control extenders, some types use an RF link
    so you can mount the set end unit inside the cabinet where your TV chassis
    IR unit can see the IRLED and you can put the box that picks up the beam
    from your handset anywhere you like. Its a more expensive option but its
    certainly safe and avoids modifying the chassis.
     
  10. Guest

    You may find that there is too much electrical noise going on inside
    the cabinet to do this. Some IR receiver modules are incredibly
    sensitive to interference. I'd recommend using shielded audio or data
    cable to do this, rather than ordinary hook-up wire.

    If you could run a piece of optical fiber from the receiver to the
    cabinet, that'd be even easier, and wouldn't create any interference
    problems for you. You can get cheap plastic fibers in six foot lengths
    or longer at electronics surplus places. Networking fibers are
    available everywhere, but I wouldn't recommend them because they are
    incredibly thin and you won't get very good coupling from six feet away.
     
  11. Guest

    Have you thought about using "mirrors" instead? I use one of the
    remote control extenders with my satellite system, but need to bounce
    the signal with a mirror as well.
     
  12. I had the same problem, doing exactly what you did.
    My tv had a scart, if yours does not it's another problem but a
    scart has a pin which can be fed with i believe 12v and will cause
    the tv to jump in ext1 mode.
    I soldered a relay in series with a capacitor so the relay would
    have a delay of a few seconds to allow the tv to start and then the
    12v feed kicked in, jumping the tv in ext1 mode.
    If that does not work for you, install the IR sensor somewhere
    else as mentioned above.
    If in doubd, ask a tv technician, it's not too complicated.

    Bart Bervoets
     
  13. oldfogie

    oldfogie Guest

    ok, I guess I follow you. Just so I'm on the same page though...there
    are a total of 5 solder points. I'm thinking that the two on the
    outside are actually holding the IR sensor to the pcb and the three in
    the middle are the brains of the unit??? Right?
     
  14. Guest

    thank you...that is one of my questions answered. Now I just have to
    figure out the best solution for wiring. "stickyfox" suggested optical
    fiber for my wiring? I'm not familiar with this and I'm really looking
    for something I could just pick up at my local radio shack. I'm
    guessing by all of these posts that it must be shielded too? Come on
    guys, brainstorm! (think Radio Shack too!)
     
  15. ampdoc

    ampdoc Guest

    I would use microphone cable for a balanced line mike. It has a Copper braid
    shield and 2 insulated conductors inside. Connect the braid to your ground
    and use the other 2 wires for the +5v and signal. The cable sould be similar
    to what they have here:

    http://dkc3.digikey.com/PDF/T061/1493.pdf

    The cable at the top of that page would work fine, Radio Shack should have
    something similar. 2 conductor with shield.

    Hope this helps.
     
  16. James Sweet

    James Sweet Guest


    Yes, the outside two are the mechanical mount though they're likely also
    grounded for shielding. The other 3 wires are power, ground and signal.

    If in doubt you might want to find someone more familiar with this
    stuff, TVs can be dangerous.
     
  17. James Sweet

    James Sweet Guest


    Hot chassis means that "ground" in the TV set is not earth ground, the
    AC line coming in is rectified and filtered into around 170VDC, the
    negative side of this is called "ground" but in reality it's floating
    well above earth ground and you'll get a shock if you touch it. Many TVs
    use a transformer in the switching power supply and are isolated but not
    all are so it's important to know what design your TV uses before you do
    too much mucking around.
     
  18. Guest

    I am trying to find circuit board schematics for this tv on the
    internet and have not been successful. It is a Memorex MT2274A set. I
    was just looking at the circuit board and specifically at the IR
    sensor. I understand that the outside left and right terminals on the
    sensor are for mounting purposes. Now the three middle ones I'm not
    sure of. If I purchase that mic cable for lengthening this setup, I
    guess I'm supposed to solder the braided ground cable from the mic wire
    to the "ground terminal" on the IR sensor. Out of the three center
    pins, how do you know which one is "ground?" I looked on both sides of
    the pcb and there is no markings, and as I said before, I have no
    access to schematics.
     
  19. I.F.

    I.F. Guest

    Try here; http://www.eserviceinfo.com/
     
  20. David

    David Guest

    Do you have an ohmmeter? See which terminal has zero ohms to a ground point
    such as the tuner case.
    Are you sure you are not in over your head?

    David
     
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