A fixture in my basement has a single 48" florescent tube which recently started flickering and now fails to start - it just flickers. I replaced it and have the same behavior. The fixture is at least 15 years old and might be much older.
I don't see anything that looks like a starter. I've searched around and see that the ballast may be the problem, but I don't see what looks like a ballast. It may very well be under a metal cover that runs most of the way under the bulb. Well, above the bulb actually.
According to this site, the problem might be trying to use a rapid-start lamp in a pre-heat fixture:
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Because the fixture is in an infrequently used small storage room (formerly a sewing room) I bought the cheapest tube they had - but I don't see anything on it about rapid-start.
I guess I can try a more expensive bulb, and if that doesn't work, unscrew the metal cover and see if I can find a ballast. It could also be the wallswitch, but that seems the least likely culpret to me.
*Remove the cover and change the ballast or just change the entire fixture. Rapid start and preheat bulbs are not interchangeable because they have different pins on the ends and require different sockets for each.
I'd look for a starter. If not, a new electronic ballast energy saver fixture at WalMart for about $11 or $12. Although the bulbs may be cheaper somewhere else.
To diagnose florescent fixtures I used to remove the starter and insert needle nose pliers to see if the bulb would light and stay lit. If it stays lit, just replace the starter. Not saying this is how you should test anything, just that it worked for me for 30 years.
There were many fixtures made that used a "start button" instead of a starter (or instead of needle nose pliers) ;-). I have a old desk lamp next to me that uses a red push button in place of a starter. (And a black push button to turn it off.)
I read that about cold temperatures but it just isn't that cold. I'm sure it isn't below 65.
Ok, having read a number of messages, the thing to do is unscrew that strip and see what's behind it. I recall starters are those cylindrical silver things so I doubt it has one, but until I look behind I just won't know. If it has a starter, I stick an insulated needle nose pliers in, after checking to make sure my insurance is paid up.
Then, if the starter isn't the problem, I replace the ballast, or maybe the whole fixture. I think Tony suggested the fixture, and it's likely what I'll do. Ballasts at Home Despot are $15 - 30, most likely the $15 one. Single fixture 48" is $19.
Now I have to pull a fair amount of crap out of that room so I can get at the fixture, and get some decent lights in there so I can see what I'm doing.
But those $19 fixtures are usually pure crap and fail rather quickly. If the present fixture and its sockets are in good shape I'd go for replacing just the ballast.
Jeff
- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) The speed of light is 1.8*10e12 furlongs per fortnight.
when I decided I wanted a short light under my kitchen cabinet. It was $15 at home De Pot or $5 at Wall Fart. So, I took the cheap one. Since I can't see under, I markered on the side where the switch is, for off and on.
I bought and installed 12 2 bulb fixtures in my garage/shop. Bought them at WalMart for under $13 each. They are Lights of America brand, I know when that company was new they had some pretty bad stuff, but it seems a lot better now. All electronic ballasts, no hum what so ever, and in the summer heat I left them on for 2 1/2 days to give them a "burn in" test. No failures. Oh, I went to L*wes and bought a case of the energy saver bulbs that are made to go in that fixture. They light fairly well in the cold also and don't take long to get to full brightness as they warm up. They aren't made like old ones but none fell apart, and I've even accidentally given a couple a good wack with a
That is NOT TRUE. There are even F40T12 bulbs rated to be compatible with both. Nowadays, F40T12 bulbs are generally compatible with rapid start ballasts, since nearly all F40T12 ballasts have been rapid start for a decade or two.
I have seen maybe 3 different ends of 4-foot fluorescents, and all that were different from the usual 2-pin ones were fairly specioalized instant start lamps requiring according ballasts.
This sounds like a starter, which in a few fixtures can only be replaced if the fixture is opened. Starters are usually but not always accessible if the fixture is only disassembled enough to remove the bulb.
Replaceable starters are cylindrical "cans" about 3/4 inch in diameter and about 1.5 inches tall. Twist counterclockwise about 1/4 turn (maybe somewhat less) and then pull to remove. For a 4-footer, the replacement starter is an FS-4.
I see some cheap fixtures last a while, especially if suspended on those chains that come with some of them to allow the cheap ballasts to cool better.
However, I have seen shortened bulb life, reduced light output and reduced energy efficiency with those cheap fixtures.
No, this turned out to be a ballast. I returned the bulbs I bought to Home Despot and spoke to the resident electrical person who confirmed what was written here, that it would be easier and better to just replace the fixture. So I did. The only snag was that the old fixture was held up by the two screws that go into the electrical box and the new one didn't have holes in that place.
Since I can't really hang it on a drop ceiling, and the new fixture is half the weight of the old one, I just drilled a few holes so the new fixture hangs on the box and it stays up.
The house wires are so old that I can't tell which is white and which is black. So I went by the wires that went into the old ballast. The wire that went to the white ballast wires was assumed to be the white one.
I wired it in, turned it on, and it worked fine. Then I tried again and only one bulb goes on. Odd. I jiggled the bulbs a bit, still only one goes on. If the wires were reversed would that make a difference?
I switched the bulbs and the one that works still works and the other doesn't. So it seems like something is wrong with one of the bulbs. Not that I care since even the one bulb is too much light for that little room.
Looks like a reasonably successful fixture transplant. Thanks to everyone for their help.
And it looks like maybe the second time in my life so far that my first guess for a fluorescent fixture problem turned out to be wrong. If I saw how it was blinking or seen a video, I would probably have recognized what was going on.
Meanwhile, as for why after first use only one bulb lights? You did say you like it that way, but this did catch my attention.
You did say that switching bulbs around indicates that one of the bulbs themselves is now refusing to work. Since the bulb is supposedly new, my first guess is that the bulb got broken somehow or was defective.
My second guess is that the bulbs have some differences between them in electrical characteristics and you have a cheaped-out-design 2-bulb electronic ballast that cannot handle above-average difference between the two bulbs (production tolerances, etc.).
(Are the bulbs new, or did you put old bulbs in the new fixture? Are the bulbs even ones that the fixture is rated to accept? There are a few different 4-footers that have the same pins.)
My third guess is that reversing the power wires will make a difference, by affecting electric field distribution within bulbs that are trying to start (or that the fixture is not grounded, which also unfavorably affects electric field distribution within a bulb that is trying to start).
My 4th guess is that the cranky bulb has a coating of dirt or grime that, if humidity gets high enough, gets conductive enough to screw up electric field distribution within a bulb that is trying to start. Since the bulb is supposed to be new, and humidity in November in a house in .com-land is not that likely to be high, I consider this to be very unlikely. This problem is more of one in coastal areas where salt gets into the air.
*You are correct. After I posted that I realized that I was thinking about instant start ballasts which are wired through the lamps and the pins are different.
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