Electrically-gifted dopers, help me fix my fluorescent light

The fluorescent light over my kitchen sink has suddenly stopped working. Well, it works, kind of. When you turn on the switch, both bulbs flicker rapidly with a very low light. The bulbs never actually turn on - just flicker. I don’t know how old the light fixture is, but if I had to guess, I’d guess at least 15 - 20 years old. It’s a 2 bulb light, and it’s hard wired in, not a plug-in. I DON’T think both bulbs would just conk out at the same time. So is it the bulbs, the ballast, the entire fixture, or something else entirely?

Thanks for all your help. I’m looking forward to once again being able to see my dishes while I wash them.

Probably just the bulbs, but it could be the ballast.
If it’s as old as you say, it’s time for new tubes anyway, so start there. Other than the ballast, there’s nothing else to go wrong, really. I’ve seen sockets crack, but that wouldn’t cause this problem.

If it’s 15-20 years old and has short bulbs (since it fits over a sink) there’s a good chance that instead of a ballast it has a starter. Look behind the bulbs and see if you see a round silver thing sticking out. About as big around as a quarter, sticking out about a half inch. That’s the starter. Pull both the bulbs out, grab the starter, give it a quarter turn to the left and it’ll pop out. Get a new one from the hardware store and replace it. If that doesn’t do it, you need new bulbs.
BTW, one bad bulb can make the other not light properly.

Boy, y’all are FAST!!!

I think the bulbs were replaced between 5 and 10 years ago. Not sure though. I’m hoping it’s just the bulbs.

I looked for a starter but didn’t find one. (Thanks for explaining that! I"ve seen that silver thing before on other fluorescent lights and wondered what it was. Now I know!) I think this is a commercial fixture instead of a residential fixture. It has never had a cover over the bulbs and is really, really fugly. I would replace the entire thing but I don’t have the funds.

Oh, and the bulbs are GE F20T12-CW-ECO. I googled that, and it seems those are commercial bulbs.

I tried rotating one of the bulbs to try to take it out, but I couldn’t get it to come out of the fixture. I feel like a total idiot asking, but is there some special way I need to take these bulbs out? (I promise I’m not as dumb as I sound - I did manage to replace my thermostat by myself.)

Thanks again.

I’m not sure what you mean by commercial bulbs. But anyways, those appear to be standard two pin bulbs. Grab and twist. There could be some corrosion from being over the sink. Sometimes it takes some muscle, but I’ve yet to break one and I’ve changed a lot of bulbs. Grab near the ends so you don’t torque the whole thing. If you have some spare bulbs, pop them in and see if it works again, otherwise it’s the ballast.
You can change the ballast, but more often then not, it’s not worth it. You’ll find out, it’ll be something like $25 for the ballast or $27 for a new fixture.

Most bi-pin sockets have the pin entrance at the top, so they are pretty easy to identify. With these sockets, you rotate the tube 90° and slide the pins out of the opening in the socket. I’ve never seen one, but i suppose it’s possible that this fixture has a spring-loaded socket on one side. Try sliding the tube to one end or the other, and then removing the free end.

With most fluorecent fixtures I’ve seen, ballast is shared by bulbs in pairs; if there’s a problem with one bulb, neither will work.
I’d suggest replacing the bulbs, and ignore the ballast until the bulbs have been ruled out.

With the smaller light fixtures it’s really not worth replacing the ballast. You can get a new light for the same amount of money.

The commercial grade 4 ft fluorescent light fixtures with 4 or 6 lamps in offices are still sometimes repaired. But, not the little short ones like you find under cabinets. Or for that matter the typical fixture they sell at Home Depot. They are just too cheaply made to mess with fixing.

When I replace ballasts at work, it’s only because we have 8 foot lights and I can replace the ballast by myself. Since the light is so long, replacing the entire fixture requires a lot more work and two people. I will still do it if the fixture is starting to show it’s age.

Just FYI. T12 ballasts and lamps are being discontinued soon and now would be a good time to replace that fixture with a T8 or a T5 one
F20T12-CW-ECO means it is a Flouresant 20 watt t12 lamp CW means cool white color lamp

That’s what I was coming in to say. Well, that, and that I’d try replacing the lamps first and if that doesn’t solve the flicker, it’s most likely the ballast. But, since the T12’s are being discontinued (and in fact already are for commercial applications where I live) it might be a good time to swap out the fixture as suggested.

Also want to add for anyone that cares, since people are tossing out things like T12, T8, etc. Lamps are measured in eighths of an inch in diameter. The “T” stands for “tubular”. So a T12 is a tubular lamp that measures 12 eighths of an inch in diameter.

CW does stand for ‘cool white’ and in this lamp’s case means 4100 K. To contrast, a “WW” (warm white) would be 3000 K. The higher the Kelvin temp, the “whiter” the lamp will appear.

It turned out to be the bulbs, which I managed to replace all by myself. I don’t know the last time the bulbs were replaced. Several years ago, I’m sure…but maybe as long as 20 years ago. The bulbs were really in there and I had to work them pretty hard to get them to come out.

What I meant by “commercial” bulbs is that when I googled the writing on the side of the bulb, I got a link to the GE page for them and the title at the top was “commercial” lighting. I’m sure this fixture is one that was originally intended to be used in a garage or workshop, instead of over a kitchen sink. Like I said, it’s fugly. No cover to hide the bulbs. But it is a two-bulb fixture, and mostly what I saw at the home store were 1 bulb lights. So I’m sure that’s why my parents originally installed it - for extra light.

Anyway, thanks so much, everyone, for all your help and information - you really helped me a lot! And now I can see while I’m doing dishes.

Now tell me, how to I open up the big cover over the 4 ft light fixture in the kitchen ceiling? I’m afraid it will just come crashing down and break. Shouldn’t there be some kind of catch or hinge or something to hold one side while the other side swings down? I’ve looked but I don’t see anything. I’m not even sure how to open it up. Any ideas?

These are usually really cheaply made, so they generally don’t have a complicated system holding the diffuser on. Sometimes it’s just spring wire that allows you to pull the cover down. Sometimes, the plastic diffuser just pushes up and back into the fixture.

Can you take a picture, there’s quite a few different ways those can open.

If the big fixture’s cover looks like it wraps around, try pulling out at the top edge - grab the edge with both hands about two feet apart with your thumbs at the bottom corner and your fingers at the top.

Usually they just need about a 1/4" of pull sideways to clear the flange and the whole thing will then pop free, dead bugs and all. :smiley:

cloud diffusers can push it or pull out, depends on what kind.

flat panel diffusers can have a hinged cover released by a spring or a hinged latch; also panels might push up and allow release of a retainer.

many styles and many methods.