Piezo-electric light bulb repair

Discussion in 'General Electronics Chat' started by wayneh, Dec 4, 2011.

  1. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    I'm embarrassed to sound like I'm pitching a product here, but in the spirit of the holidays I have to share this. I'm in awe of a tool I bought today called the Light Keeper Pro, for diagnosing and fixing Christmas light strings. If your chores include fixing light strings, this is a must-have tool. You can find You-Tube demo videos, and they're legit.

    I bought the tool to find the bulbs that make the string go dark. I've done this chore for years with a DMM and I'm quite good at it, but it's annoying and tedious, especially once the lights are hung. I read the patent for this tool, and was intrigued to read that it includes a high-gain inverter to detect the small electric field of a "hot" string versus a dead portion, with no direct contact. No more pulling bulbs with my thumbnails! Where the transitions are, from hot to cold, indicates where the bad bulbs are. Clever, and I considered making such a thing myself. As a guitar player I figured, how hard can it be to detect 60-cycle hum? Hard not to. For $20 locally, I'm glad I didn't bother.

    I guess it finds bad bulbs OK with its field detector, but the amazing thing is that this tool generates a piezoelectric zap that actually repairs the open shunts of bad bulbs, allowing the string to light up. And it really works; I pulled the trigger all of three times tonight and repaired three dead strings quick as that. Once they light again, it's easy to replace the bulbs that are out.

    I never got around to using the field detector for scanning the strings for the bad bulbs, since I was able to light them all up by zapping them instead. The instructions make it clear that searching for the offending bulbs is the last resort, to be done only after using the zapper until there's no hope that more zapping will fix the string.
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  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Thanks for the info. I've been monitoring a flag with 20 strings of 13 bulbs ea- problem is there is no plug, they run from 120 Hz pulsing current. When a bulb fails to short on failure, have to resort to using a high gain audio amp & listen for the bad bulb. Have chainged maybe 15 bulbs in 7 years. I'll look for a Light Keeper for functions other than the zap.
     
  3. Audioguru

    New Member

    Dec 20, 2007
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    For a few years, my electrical utility company has been giving away LED Christmas lights for free when a set of old incandescent ones (working or not) are turned in. Then a lot of electricity is saved and the LEDs hardly ever burn out.
     
  4. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Not sure I understand your [Bernard's] comment. This tool can connect to your light string via the normal power plug if you have to, which I guess is not an option in your case, but the normal and recommended connection is by plugging the tool into a bulb socket as though it were a bulb itself. The zap is delivered into the bulb socket, and amazingly repairs the shunts of the other bulbs on the string.
     
  5. wayneh

    Thread Starter Expert

    Sep 9, 2010
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    Yeah, that was part of my reluctance to buy this thing, since it should become obsolete in a few more years as my strings get replaced with LEDs. In fact I'd have done that already but my wife hates the pulsing of the LEDs.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    LED Christmas lights blink like the rear LED lights of new cars, busses and trucks.
    LED lights on bicycles blink a little slower.

    Also, they are not bright enough.
     
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