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Thread: lcd monitor wiring help

  1. #1
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    lcd monitor wiring help

    firstly hello and congrats on a lovely forum,

    a friend of mine has given me this lcd screen, now it came from a cheap in car dvd system. the wire shown came with an s-video (style) plug which plugged directly into the said dvd player. the dvd player would have been powered by a cigarette plug in affair. the dvd player itself is now broken and as such i need to power this monitor on its own, hence why i have chopped the plug off to see what im left with.

    my headunit in the car plays dvd's and has video and sound out (this is in the RGB format) ie one yellow plug for video, 1 red + 1 White for audio - the same as you would see on most home televisions.



    What i need help with is what colour cable does what so that i can begin hard wiring this in.

    i would have expected to see:
    1 x wire for 12v power
    1 x wire ground/eart
    1 x wire video
    1 x wire audio (left channel)
    1 x wire audio (right channel)

    as you can see there are 6 wires so i'm confused.

    so can someone please help me with what colour wire does what.

    also will i be requiring some sort of regulator when wiring the 12v power cable, if so where do i go about getting one of these.

    thanks for your time and sorry for the big post

  2. #2
    Banned Motorcity's Avatar
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    why don't you just open the lcd up, and look at where the wires are going on the controller?
    I am sure you can figure out which wires are power and ground using a meter, then simple trial and error with a known good video or audio signal to determine your A/V wires.
    There is no standard when it comes to the colors of those leads, so basically who the hell knows what wire is what.

  3. #3
    Newbie mp3gtr's Avatar
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    Have you got the plug with the wire colours on it? Would the plug help in identifying the purpose of each wire colour?
    Maybe the dvd player output still shows 12v on one of its wires.
    There is a good possibility that the ground for video, audio and power are separate wires. Are you sure its stereo?
    ---12v
    ---GND
    ---Video signal
    ---Video GND
    ---Audio signal
    ---Audio GND

    HTH

  4. #4
    Newbie NotSoBlurr's Avatar
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    There should be 2 different connectors for power (12V, Gnd and ACC) and signal (Audio, video and parking brake).

    Manufacturer normally do not combine the power and signal connectors together so as to prevent interference or noise.

  5. #5
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    thanks for the replies people

    this cable definatly carries power as well as video/audio, it says so in the manual, plus there are no other inputs for power...... basically the cable that would have plugged into this wire has a yellow male pin for video and then 2 for audio - hence why i assumed its stereo - this then splits again to provide the power.

    if i take the back off to have a look and see im sure i can make an educated guess as to what wires are power and earth. a multimeter wont help surely if there is no power running thorough it... or have i missed something?

    im not too worried about sound as it will mainly be used to display video only (displaying a detailed mp3 playlist on dual layer dvd) although it would be nice so my partner can watch films with headphones as this screen has a headphone socket.

    unfortunatly i cant test the dvd player with a multimeter to see what wire is the power one as it has been thrown away now.

    i'll take it apart tonight and post pics of the circuit board where the cable joins it to see if anyone can help as to what wire does what... to be honest i can figure out audio/video just as long as i have power.

    also any comment on needing a regulator "egg??" for the power.

    once again thanks for your help in this matter.

  6. #6
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    right so ive taken the unit apart and looked at where the wires are soldered to the circuit board.

    at the point where each wire is soldered the following is printed:

    • green wire = +12v (self explanitary).
    • black wire = nothing printed on the board but wire is slightly to the right of where the rest are soldered (assume this is my main earth/ground).


    • white = A1 (assuming this is audio - mono signal???)
    • red = V1 (assuming one of the 2 video signals)
    • Yellow = V1 (assuming one of the 2 video signals)
    • blue = G (another earth/ground - but for audio or video?)


    this unit has selectable AV sources ,, ie Av 1 and AV 2 much like on most TV's so im guessing those are the red and yellow wires. hence the V1's shown above.

    what im confused about is the G (blue wire) what will this be for..... i guess i need to cut a few av cables to see what ive got.

    so can anyone comment on the above. and correct me if im wrong or point me in the right direction?

    thanks again.

  7. #7
    Banned Motorcity's Avatar
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    Quote Originally Posted by vinylconflict View Post
    right so ive taken the unit apart and looked at where the wires are soldered to the circuit board.

    at the point where each wire is soldered the following is printed:
    • green wire = +12v (self explanitary).
    • black wire = nothing printed on the board but wire is slightly to the right of where the rest are soldered (assume this is my main earth/ground).
    • white = A1 (assuming this is audio - mono signal???)
    • red = V1 (assuming one of the 2 video signals)
    • Yellow = V1 (assuming one of the 2 video signals)
    • blue = G (another earth/ground - but for audio or video?)

    this unit has selectable AV sources ,, ie Av 1 and AV 2 much like on most TV's so im guessing those are the red and yellow wires. hence the V1's shown above.

    what im confused about is the G (blue wire) what will this be for..... i guess i need to cut a few av cables to see what ive got.

    so can anyone comment on the above. and correct me if im wrong or point me in the right direction?

    thanks again.
    Ok, so you are almost there. If you have a meter, set it for continuity, and probe the black wire and the mounting holes of the controller (this opening will be a ground point on the board) if you have continuity (meter will beep) then you know the black wire is a ground. Same for the blue wire. Although I suspect one of those is a trigger wire.
    Since you have all the other wires mapped out for you, you are good to go. Lucky bastard, most PCB's don't spoon feed you like that!

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    Quote Originally Posted by Motorcity View Post
    Ok, so you are almost there. If you have a meter, set it for continuity, and probe the black wire and the mounting holes of the controller (this opening will be a ground point on the board) if you have continuity (meter will beep) then you know the black wire is a ground. Same for the blue wire. Although I suspect one of those is a trigger wire.
    Since you have all the other wires mapped out for you, you are good to go. Lucky bastard, most PCB's don't spoon feed you like that!
    nice one for the tips there....

    things have changed a little tho.... the G is ground/earth

    the black wire is an accessory wire that conect to reverse signal (in the car) which turns the monitor off (read it in the manual)

    av1 and av1 are still as above although im confused as the wire is single core where as all composite cable have to cores.... a centre core and then an outher cor which sends a "reference" signal for the voltage.... ie a second ground...

    dont know how to get around this...... any advice?

  9. #9
    Banned Motorcity's Avatar
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    the video feed uses signal and ground. that is why you see 2 seperate wires in the cable. The v1 red and v1 yellow are the signal feeds and the ground for these feeds would tie into G (blue wire)
    That is of course if the display supports 2 seperate video input feeds to begin with.

  10. #10
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    so th4e video feeds share the same ground (earth point) as the rest of the unit?

    thanks for your help by the way

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