irregularly flickering LED lights

Discussion in 'General Electronics Chat' started by Mike Badera, Aug 2, 2015.

  1. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    i have three LED lights in one circuit/fixtures that used to have small incandescent spot lights. at random the lights start to flicker... they all flicker at the same time same frequency. i can't tie it in to "the AC is on" or any other high draw electrical problems... sometimes turning off for 10 minutes seems to do something... other times it is "try again tomorrow"... any help much appreciated?
     
  2. #12

    Expert

    Nov 30, 2010
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    First impression: Get your ladder out. You're going to have to get in there and look for crusty connections.
     
  3. ian field

    Distinguished Member

    Oct 27, 2012
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    From time to time, I see intermittent LEDs with fractured bond wire due to thermal cycling - any other LEDs in series with the faulty one will also flicker.

    I had an LED bicycle light that did a fair impersonation of Morse code after it'd been on a while - no amount of flexing or prodding the PCB could provoke the fault.

    Similar problem with a second hand PC tower case - someone had wired the PWR LED to a Molex connector with no current limiting resistor. The LED lit, but started flashing ever faster as it heated up.
     
  4. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    All three are on the same circuit. When they start flickering I can unscrew any one of any two and the other(s) keep flickering. Sometimes it is days if not weeks between when it happens other times it might be two days in a row m
     
  5. Brownout

    Well-Known Member

    Jan 10, 2012
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    Are you sure they aren't "flicker" LEDS?
     
  6. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    Yes. Most of the time they are steady/normal
     
  7. Brownout

    Well-Known Member

    Jan 10, 2012
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    How do you power them? Can you describe the modifications you made to the light fixture to power the LED's?
     
  8. #12

    Expert

    Nov 30, 2010
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    Congratulations. You have determined that the problem is not in any one LED socket. It is farther back in the power line, as in, "closer to the circuit breakers than the sockets are". Keep up the good work.
     
  9. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    I didn't do anything special. I took out the three small floods from the display and replaced with off the shelf LED. I've been back to the switch. The power splits and feeds two circuits. The other circuit has different LED lights and none of them ever flicker.
     
  10. #12

    Expert

    Nov 30, 2010
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    You seem to have determined that the problem is between the switch and the sockets.
     
  11. Brownout

    Well-Known Member

    Jan 10, 2012
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    Are these LED bulbs? I was thinking about the small LED's that normally run on low voltage DC power. If so, try to screw one or more into a different fixture and see if they flicker. That would point to faulty bulbs.
     
  12. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    That's kind of what I thought. But looking where the cable run is there appears to be nothing between the switch and first pot that would be a problem. Nomother connections no splices. Nothing. I'm at the point of putting back the little incandescent floods just to see what happens m
     
  13. #12

    Expert

    Nov 30, 2010
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    Pot? This is the first mention of a potentiometer. Are you calling a socket a pot?

    Trying the original lights is a valid maneuver, but it is very unusual that 3 LEDs would flicker in unison because all three of them are identically defective.
     
  14. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    No pot like "pot light" in a ceiling
     
    #12 likes this.
  15. Brownout

    Well-Known Member

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    I would keep that under my hat, if you know what I mean :D
     
  16. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    I don't believe all three would be defective even if from same lot. And I can't believe all three would be damaged
     
  17. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    Maybe can light fixture in the ceiling.
     
  18. Brownout

    Well-Known Member

    Jan 10, 2012
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    Only testing will tell for sure.
     
  19. Mike Badera

    Thread Starter New Member

    Aug 2, 2015
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    Agreed. The other thought was to take them out and replace with old lights. Then put each one into diff fixtures/circuits and see what happens over a week.
     
  20. Brownout

    Well-Known Member

    Jan 10, 2012
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    That sounds like a good idea.
     
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