Strange issue with a 4' fluorescent light fixture
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  1. #1
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    Default Strange issue with a 4' fluorescent light fixture

    One fixture, 2 lamps side by side and end to end. 2 ballasts, one for each pair of bulbs. No starters. It worked fine for years. Now you turn the wall switch on and nothing happens. If you touch one of the bulbs that pair lights up instantly, then touch one of the other pair and it lights up instantly as well. Avery light touch will do it, I am not rotating the bulbs to get a better contact on the pins. WTF?

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    john,
    One of mine did the same thing. Maybe it's static el.

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    Moonlight, you clearly have the magic touch. Look into hiring yourself out to fix all the other things that don't work.

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    Not sure about other types, but most T5-HO lamps need a grounded reflector or other surface nearby to start reliably. Could you have lost the ground to the fixture?

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    time to retro fit led's in that fixture

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    I have 2 4' doubles that have been doing it for a couple years
    Usually when it's cold
    Rub across the bulbs with my fingers and they're on.
    Glad I'm not the only one this happens to
    These 2 light sets are on the led replacement scedule

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    Quote Originally Posted by moonlight machine View Post
    One fixture, 2 lamps side by side and end to end. 2 ballasts, one for each pair of bulbs. No starters. It worked fine for years. Now you turn the wall switch on and nothing happens. If you touch one of the bulbs that pair lights up instantly, then touch one of the other pair and it lights up instantly as well. Avery light touch will do it, I am not rotating the bulbs to get a better contact on the pins. WTF?
    Bend the contacts on the fixture to get better contact. Might be metal fatigue from heat cycles? Had it happen to one of my lights. Try LED bulbs, if you replace the florescent ones. No warm up and they don't need a ballast (and better CRI)

    Sent from my SAMSUNG-SM-G891A using Tapatalk

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    Quote Originally Posted by 52 Ford View Post
    Bend the contacts on the fixture to get better contact. Might be metal fatigue from heat cycles? Had it happen to one of my lights. Try LED bulbs, if you replace the florescent ones. No warm up and they don't need a ballast (and better CRI)

    Sent from my SAMSUNG-SM-G891A using Tapatalk
    I was born at night, but not last night. I know how to correct the issue, replacement is no problem. Did the contact deal and replaced the tubes. same issue. I want to know why it is happening. How can they light up with the lightest touch.

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    Could be your fingers/body are adding capacitance, helping whatever not-quite-strong-enough starting voltage to ionize the gas in the tube.

    Somewhat different deal, but some capacitance switches will operate when a finger gets close; and not even touching.

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    Quote Originally Posted by moonlight machine View Post
    One fixture, 2 lamps side by side and end to end. 2 ballasts, one for each pair of bulbs. No starters. It worked fine for years. Now you turn the wall switch on and nothing happens. If you touch one of the bulbs that pair lights up instantly, then touch one of the other pair and it lights up instantly as well. Avery light touch will do it, I am not rotating the bulbs to get a better contact on the pins. WTF?
    Quote Originally Posted by TGTool View Post
    Moonlight, you clearly have the magic touch. Look into hiring yourself out to fix all the other things that don't work.
    Yup, he's touched....
    Attached Thumbnails Attached Thumbnails dilbert-iit-fire.jpg  

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    Quote Originally Posted by moonlight machine View Post
    I was born at night, but not last night. I know how to correct the issue, replacement is no problem. Did the contact deal and replaced the tubes. same issue. I want to know why it is happening. How can they light up with the lightest touch.
    When you touch the tubes, you are adding capacitance to the circuit which does increase the current flow during part of the cycle and sort of triggers the tube start. If you had an electronic ballast, it is likely that you would not have this issue.

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    Its the low level of mercury now used in fluorescent tubes. Yes, it is the need of a ground plane but also higher strike voltages to establish the arc. Most likely you have magnetic ballasts that don't provide the really high voltage needed to strike the arc. If you want to continue with the fluorescents, change the ballasts to electronic. Better yet change to LED

    Tom

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    Quote Originally Posted by Ray Behner View Post
    john,
    One of mine did the same thing. Maybe it's static el.
    That's what I suspect. Fluorescent bulbs require a high starting voltage.

    Other possibility is that the pins or sockets are oxidized enough that touching the bulb micro-wipes the contacts enough to work.

    PS: I don't like LED bulbs for area lighting so I replaced several older ballasts with electronic.

    Fairly inexpensive on Amazon and make a world of difference.

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    I've got a few doing the same thing- and they have electronic ballasts. Replace the lamps, life is good, climb down, shut them off and then back on- nothing!

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    You a capacitive kind of guy. If this thing happens every time then there is a saying in the business. "It's fixed".
    If you touch the tube with a eraser (insulator) and it lights then the issue is mechanical. If you touch with your
    hand then it's electrical. Would be interesting it you tried it with bare feet and see if the start time increases
    or decreases.

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    I had 2- 8' fluorescent 2 bulb light fixtures start blinking and I replaced the bulbs as they were dark at the ends, that didn't do it. I bought 2 ballasts at an an auction for a bargain and replaced one. It was a real pain standing on a ladder reaching overhead. That didn't help. I finally went down to Home Depot and bought a $25.00 LED 4' single bulb light fixture, hung it up and bingo it worked. Someone suggested I buy 4 - 8' LED's bulbs to replace the old Fluorescent ones and wire direct. They would cost $175.00. No Thanks....I bought another cheap LED and I'm happy.

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    I agree with the theory that the ballast (of whatever kind) is no longer providing a strong enough HV pulse to reliably strike the arcs in all tubes, even if the tubes are not new. When the pulse is only just sufficient, suddenly the phase of the moon matters.

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    Really weird is it not?
    Your touch on the outside of the bulb adds something that helps start the ignition, that tiny bit when unable to do it alone.
    Bob

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    Nope. Not weird at all. As I said above, a lot of these fixtures require a significant ground-plane near the tube to start, and that's with an electronic ballast. This is possibly a variation of that.

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    Would be interesting if you touched the surface after grounding your hand. Then do it again without the ground, you
    could even call your longest haired employee and run a comb through his hair to charge you up with excess electrons
    before the touch.

    In the past I have walked around the concrete floor with bare feet and turned on a machine here and there. I wouldn't
    exactly call it naked machining, but I have felt little tiny tingle sensations on my feet. All my electrical is wired
    correct the floor is not actual ground.

    Advice from a LED bulb owner:
    I bought 8 footers about a year ago. Removed those failing ballasts and simply connected a couple of wires. No regret.


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