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Fluorescent light fixture question

Discussion in 'Electronic Repair' started by [email protected], Jul 5, 2004.

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  1. Guest

    I have a 2 bulb, 48", Fluorescent light fixture.
    90% of the time when I turn the switch on, it does not start.
    There is a little flickering in the end of the bulb.
    I turn the switch to off and back immediately turn it back on and it
    lights.
    My first guess was the ballast. It is a type "P". so I put in a new
    ballast, rapid start, and two new bulbs. No change.

    Any ideas ? I'm al out.
     
  2. Li Gangyi

    Li Gangyi Guest

    did you ground the fixture??
     
  3. gothika

    gothika Guest

    Could the contact points in the connectors be corroded?
    Also might be a case of voltage to the fixture being down a few volts.
     
  4. Li Gangyi

    Li Gangyi Guest

    if u're willing to shell out a few more bucks...maybe u can get some new
    electronic ballasts...they work over a wide range of voltages and give out a
    higher light output...costs around $20SGD which is around USD$9+ here in
    Singapore...
     
  5. But maybe the only problem is that the fixture isn't properly grounded....

    --- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  6. Are you sure you have the input wires wired correctly. If you reverse
    the hot and neutral wires on the input, you can get the effect you are
    describing when the ballast is marginal in its output.

    H. R. (Bob) Hofmann
     
  7. Asimov

    Asimov Guest

    "" bravely wrote to "All" (04 Jul 04 22:23:26)
    --- on the heady topic of "Fluorescent light fixture question"

    gr> From:

    gr> I have a 2 bulb, 48", Fluorescent light fixture.
    gr> 90% of the time when I turn the switch on, it does not start.
    gr> There is a little flickering in the end of the bulb.
    gr> I turn the switch to off and back immediately turn it back on and it
    gr> lights.
    gr> My first guess was the ballast. It is a type "P". so I put in a new
    gr> ballast, rapid start, and two new bulbs. No change.

    gr> Any ideas ? I'm al out.

    My guess is it was wired with the wrong polarity. As you might guess,
    the high voltage terminal of the ballast winding must end up on the
    outside. If it ends up on the inside it is right next to the metal
    core and the voltage doesn't build up high enough, perhaps due to the
    wrong amount of stray capacitance. The wiring diagram in the fixture
    will show the proper connections to make. However, the house wiring in
    that circuit may have the wrong polarity. It doesn't matter for
    ordinary lamps but it often does for fluorescent lamps, as these have
    a hard time starting if wired with the wrong AC line phase.

    A*s*i*m*o*v

    .... Email returned to sender -- insufficient voltage.
     
  8. Luddite

    Luddite Guest

    are the new bulbs the energy saving type?
    they are rated at 34 watts and will not start with some ballasts
    get the energy hogs and check the ground too.
     
  9. Guest

    Thanks all for the responses.
    I feel it may be the voltage or the ground.
    I can not try until the end of July
    I will try them and let you know what it was

    Thanks again !!
     
  10. James Sweet

    James Sweet Guest

    Sounds like what happens when the metal casing of the fixture isn't
    grounded.
     
  11. Ken Weitzel

    Ken Weitzel Guest

    Hi...

    Is it possible that it's a new installation, plugged
    into one of those incandescent socket adaptors?
    With the ground plug bent over or sliced off?

    Ken
     
  12. Stan

    Stan Guest

    }> I have a 2 bulb, 48", Fluorescent light fixture.
    }> 90% of the time when I turn the switch on, it does not start.
    }> There is a little flickering in the end of the bulb.
    }> I turn the switch to off and back immediately turn it back on and it
    }> lights.
    }> My first guess was the ballast. It is a type "P". so I put in a new
    }> ballast, rapid start, and two new bulbs. No change.
    }>
    }> Any ideas ? I'm al out.
    }
    }Sounds like what happens when the metal casing of the fixture isn't
    }grounded.


    ??? What does grounding the case have to do with it?

    If everything is wired correctly, the ground path should have
    nothing to do with the circuit operation, right? (only the HOT and
    NEUTRAL paths are used).

    Stan.
     
  13. Not for fluorescent fixtures. Although there is no direct circuit through
    the Ground, the capacitance between the lamp and Earth ground is needed
    for starting.

    More in the F-lamp FAQ.

    --- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  14. Guest

    I said I would post a follow up after I got back.
    So, Here it is.
    It is working fine now. No changes.
    I checked everything everyone suggested, but I did not replace any
    additional parts.
    I bought the contacts just in case. they were cheap.

    Thanks to all for the help and suggestions.
    This is a GREAT group !!

    Glenn
     
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