Honey I blew up the pixels!

Discussion in 'Tips and Tricks' started by scamper, Aug 31, 2016.

  1. scamper

    scamper Senior Elf

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    I actually need some advice from anyone who has been here before me.
    I was wiring up a new prop today and have 20 pixels that are 5v and 4 that are 12v, so I decided to use a buck converter and run the prop on 12v.
    Now comes the problem, after spending hours wiring it up and getting interrupted every 5 minutes, i hooked it all up and turned on the power befor realising I hadn't adjusted the output of the converter.
    long story short, I heaped 12v onto the 5v pixels and now they don't work.
    What is the best way to try and work out which pixels do and don't work.
    It was an absolute pain to mount the pixels in the first place, so i don't want to do the whole lot again if at all possible.
     
  2. kel

    kel Dedicated Elf

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    I think ShellNZ is a fairly experienced user, so may offer to assist ...
     
  3. ShellNZ

    ShellNZ Senior Elf

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    Sorry cant really make any suggestions, just wanted to say, been there, done that. I hand-made my pixicles with 5v strip. Last year I was up on the roof and looking at power supplies upside down. Saw what I thought was 5v and plugged the pixicles in, quarter of the house worth of pixicles. They twinkled on and did weird things, rebooted a few times, did the same thing. Turned out to be the 12v PS beside it that I hooked them into :( I saw the S-350-12 and thought it was a 5 at the start, ugh.

    I spent half a day trying to figure out what worked and what didnt, it was so messy I just made the whole lot again, thankfully I had some strip (had to use white instead of black PCB though) left.

    Shell
     
  4. the grinch

    the grinch I guess I could use a little social interaction

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    I feel your pain scamp sorry cant help but have similar experience although didn't blow up anything up spent many hours cutting pixel strip and extending sections with ribbon cable heat shrinking etc etc to find had faulty strip as every time would touch individual pixels under test lights would flash or simply cut out assuming dry solder joints or similar . So anyways as I did chin up mate and soldier on .
     
  5. darylc

    darylc Full Time Elf Global Moderator

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    Try cutting out the first few pixels. Last time I did that, the first pixel or the first few were completely fried, after that a lot of the pixels (but not all) actually did work. Was a pain to cut out all the dead ones though.
     
  6. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    Because each pixel is connected in parallel with the power then what you will find is that at least the first few would have blown and then hopefully after that the rest are OK due to the voltage drop created when the chips fried, but sometimes it may cause more damage than that.
     
  7. jerrymac

    jerrymac Apprentice Elf

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    Really feel the pain.
    Applied 12 volt to 6 stings of 5 volt pixels. blew the first few of each sting and a few others at various places. Cut out and replaced all the dead and crazy ones.
    Got distracted and Re-applied 12 volts to the same 6 stings. needless to say the new magic smoke got out also.
    Again replaced dead and crazy ones and now Triple check EVERY time then check twice more before flipping the switch.
    HOPE I learned my lesson. (but likely not :) )
     
  8. Wolfie

    Wolfie Full Time Elf

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    Man, I can only imagine.

    This is why I am cycling out all 5v pixels and eventually will have only 12v to deal with.

    Also, I am using a different pigtail as I migrate to 12v so it will be impossible to plug 12v into a 5v prop with the pigtails being different sizes.

    My instinct, if I were in the OP's position is to replace ALL of them that had 12v applied. I would think chances of failures during the show season would be higher on these pixels. Would you rather deal with it now or deal with them at showtime?

    Once replaced you could test the ones you pulled out as candidates for emergency surgery/replacements.
     
  9. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    I agree as there is a high chance that many of the surviving pixels may have been stressed by this because they would have all had a higher voltage put into them regardless if it was only for brief period. So you may see some premature failures when using these.

    to avoid this in the future then the cheapest and easiest way is to use a bit of white tape near the plug with either 12v or 5V written on it, even better use red tape for 12vdc and blue tape for 5vdc that way you can easily differentiate between the 2 voltages. The best fix is to use different plugs so you cant physically cross the 2 voltages.

    Im sure its a mistake you wont do again
     
  10. OP
    OP
    scamper

    scamper Senior Elf

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    Thanks for all the replies.
    I ended up removing them all and out of 20, there were only 2 that survived. So I replaced them all.
    The problem was not that I put 12v on there accidentally, more that I didn't adjust the buck converter.
    Needless to say I am opening them all up and setting them now!
     
  11. jerrymac

    jerrymac Apprentice Elf

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    .........................

    to avoid this in the future then the cheapest and easiest way is to use a bit of white tape near the plug with either 12v or 5V written on it, even better use red tape for 12vdc and blue tape for 5vdc that way you can easily differentiate between the 2 voltages. The best fix is to use different plugs so you cant physically cross the 2 voltages.

    Im sure its a mistake you wont do again



    Good idea with the tape Even though I already had the 12V stings and power connector marked with RED electrical tape wrapped around the wire at the water proof plug and Green electrical tape on the 5V plugs. not paying attention with what Power Supply, I was plugging them into (also marked with colored electrical tape) resulted in the double disaster.


    REMEMBER !!! SLOOOOOOW down check three time then double check again before applying power!!!


    Try to keep all your pixels the same voltage.


    NOTHING is really Dummy proof !!
     
  12. David_AVD

    David_AVD Good news, everyone!

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    So the take away from this is don't underestimate the dummies? lmao :D
     

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