Led watch circuit malfunctioned due to hand touch.

Discussion in 'General Electronics Chat' started by Ujwal Bhagat, Jan 30, 2016.

  1. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    Hey, I have Just brought this cool led watch from amazon (https://www.amazon.in/gp/aw/d/B013FVS8SG/ref=yo_ii_img?ie=UTF8&psc=1)
    I was guessing how it was made, so I opened it disassemble it and start it (you need to our that button on the watch to see time ) sudden the Nano led which was under my finger stop working. I was surprised. So I touched other led they also stopped working. My first thoughts were that the led burned out. To confirm it I tuned my digital multimeter to continuity testing mode and test each led. Surprisingly they were all working. Though the watch was not working. I will post pic in 15 minutes. Please help me.
     
  2. ISB123

    Well-Known Member

    May 21, 2014
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    Check it with diode test.
     
  3. dl324

    Distinguished Member

    Mar 30, 2015
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    Try resetting by removing the battery long enough for the circuitry to bleed off any residual voltage and reinserting. There might be a reset button, but I would advise you to avoid doing additional damage by poking around when you don't know what you're doing.

    Regardless of whether it works, treat this as a life lesson to not disassemble everything you get unless you're willing to pay the consequences.
     
  4. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    I have checked the Nano led they are working
     
  5. SLK001

    Well-Known Member

    Nov 29, 2011
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    Curiosity killed the cat. Fortunately, curiosity will also teach you what not to do next time, so you don't kill the next cat.

    Don't worry. 99.9% of those here have" killed a cat" once or twice before in their lives. Part of the learning process.
     
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  6. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    I did it. It doesn't work.

    Moderators note : removed commercial link
     
    Last edited by a moderator: Jan 30, 2016
  7. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    The body
     
  8. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    The circuit on which the Nano led are mounted.
     
  9. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    Closer view of mounted Nano led
     
  10. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    Rear view
     
  11. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You probably have broken the bonding wires.

    Bertus
     
  12. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    Gui
    Guide me please. Should I use my soldering iron on these Nan leds. Should I check the continuity from the origin to the led.?
     
  13. dl324

    Distinguished Member

    Mar 30, 2015
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    You can't use a soldering iron on bonding wires/pads; they're far too fragile.
     
  14. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You most likely can not repair the wires.
    They are to thin and connected directly to the led crystal:

    Ujwal_img_20160130_220328.jpg

    Bertus
     
  15. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
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    OK now I got the situation, when I touched the led I broke the very delicate wires from the led. Might Try to repair.
     
  16. dl324

    Distinguished Member

    Mar 30, 2015
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    You won't be able to repair unless you have access to a bonding machine. The LEDs have 2 contacts; one on the bottom which is conductively epoxied (possibly soldered) to a pad, and one on the top that requires a bonding wire to the PC board.
     
  17. absf

    Senior Member

    Dec 29, 2010
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  18. SLK001

    Well-Known Member

    Nov 29, 2011
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    Yep... that kitty has been killed!
     
  19. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
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    Thanks to all who helped me alot.
     
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