Fluorescent light fixture question

[[email protected]]

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.

 

[Li Gangyi]

did you ground the fixture??

 

[gothika]

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.

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

 

[Li Gangyi]

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...

 

[Sam Goldwasser]

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.

 

[H. R. Bob Hofmann]

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...

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

 

[Asimov]

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

gr> From: [email protected]

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.

 

[Luddite]

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.

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.

 

[[email protected]]

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 !!

 

[James Sweet]

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.

 

[Ken Weitzel]

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.

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

 

[Stan]

}> 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.

 

[Sam Goldwasser]

}> 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).

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.

 

[[email protected]]

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