LEDs on a keyboard.

Discussion in 'General Electronics Chat' started by Alecc12, Feb 24, 2013.

  1. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    Hello everyone !

    First of all , I want to say I'm a little bad at English and I'm a newbie in electronics .

    I have a little problem with my keyboards LEDs

    I have the 3 LEDs from the (numlock,capslock and scrolllock).on the main board of the keyboard.(by board i mean the green thingy that has resistors and such , on it).
    Beside those 3 LEDs i have 8 more , 3 on one side , 3 on the other and 2 on top.From the main board of the keyboard, 2 wires leave into 3 different boards that hold the others 8 LEDs (3, 3, 2)From the main board 2 wires leave into a board with 3 leds , then 2 wires leave into a board with 3 leds and then into the last one with 2 leds.I opened to see if it has any lose "wire slots" ?Things that have wires connected into them and you insert them in the board.white square thing.

    The problem is that sometimes the others 8 LEDs start becoming more brighter or dimmer , like less electricity goes into them , flickering i guess but sometimes they don't.The flickering starts either when i start the computer , or in time.They don't have an exact moment when they do that.When i write on the keyboard, when i don't write Etc.

    Thanks alot !
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Is this a USB Keyboard?

    Can you take a couple of clear photos of the keyboard, both sides of the PCB w/LEDs. You can attach them to your next post using the paper-clip icon in the Advanced/Full Editor (not in Quick Reply).
     
  3. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    1.jpg 2.jpg 22.jpg 3.jpg 4.jpg

    It's a Hama Exodus.

    Pictures in order of name :

    1 -> main PCB i guess it's called , where the cord comes.(left side)
    2&22-> where the first series of 3 leds are.(left side)
    3-> the second series of 2 leds(top)
    4-> the other series of 3 LEDs(right side)

    Yes its a USB keyboard.It's a pretty cheap one but i like to stick my nose in things and fix them ! :D

    PS: Today the LEDs where very very low , barely 10% of the power of a LED.And sometimes they flicker.
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    One the back of the LED boards are there one or more little black SMD resistors (1mmx2mm maybe twice as big) on each board, or just one?

    The main board with the epoxy blob is the controller, the blob is the "brains", it's an IC that is physically bonded to the circuit board, then the connections from the board to IC are made, and a blob of epoxy is put over it to protect it. This saves cost when using custom chips in mass production, since adding an IC package with pins increases the cost by 25 cents.

    If it is plugged in as shown, do the LEDs all appear the same brightness? I'm assuming this is a backlit keyboard so the keys glow in the dark?

    Sometimes the dimness can be caused by the LEDs not pointing in the exact right direction, but that wouldn't explain flicker.
     
  5. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    one second i will check for the resistors.

    The thing is that all the LEDs flicker at the same time , its not from not from one certain board with 2-3LEDs , its from the main one , i think.

    PS : the leds from the main board , the numlock caps lock and scrolllock , dont have any problems , they are lit normally .
     
  6. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    IMAG0200.jpg IMAG0199.jpg

    these are the 3 led board .sry i write with onscrn keyboard

    is it anything that can be done?
     
    Last edited: Feb 26, 2013
  7. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    I just wanted to say that your English is very good. I'm understanding you perfectly, which is more than I can say for some native English speakers here :D

    Keep up the good work, and good luck with the keyboard.

    Regards,
    Matt
     
  8. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    now they are very low lit , idk why.

    still didn't get any straight answer....
     
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Are all of the LEDs are connected to the main PCB by only the red and black wires, which chain one board to the next?
     
  10. Alecc12

    Thread Starter New Member

    Feb 24, 2013
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    yeah,I found the problem.
    The top board with the 2 LEDs was "broken".
    If i connect only 3 leds , they work perfectly.If i connect 6 , 3x2boards, they work.But if i connect one board with 3 leds with the one with 2 leds , they dont work at all.I connected only 6 leds and i will change the board with the 2 leds.

    Thanks for the help !
     
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