Fluorescent fixture problem

I've got this fluorescent fixture in my kitchen which has two round 12" 32 watt tubes inside... they are each connected to their own ballast. The fixture is probably only a couple of years old (haven't had the house that long, but it looks fairly new)
90% of the time the fixture works fine, once in a while though the tube on the right goes out, it eventually comes back on it's own. Turning the lights on and off won't restart it, it just eventually comes back on...
At first I thought it was a bad tube, so I swapped the left tube with the right tube to see if it was the tube or something else.. The tube on the right continues to go out, so it doesn't sound like it's the tube. The one on the left side remains unaffected.
If it was a wiring problem I'm thinking it would probably impact both tubes at the same time, also if it was wiring it should probably have shown up before now, or be more consistent (IE just stay off all of the time)
Does this sound like the ballast is going... I would think that if the ballast was going, that it would just die, and not work 90% of the time, then die, then come back...
Any thoughts?
Thanks
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Mark wrote:

I'll bet that the ballast on the "bad side" has a thermal intermittant problem which causes it to develop an open circuit when it warms up enough and then goes away when it cools down.
You *could* go to the trouble of swapping the ballasts like you did the tubes, but if it was me I'd pick up a new ballast, install it and see wot happens.
Jeff
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Jeffry Wisnia

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Mark wrote:

It could be the ballast. You eliminated the most likely cause. I would check to make sure all the contacts are good and that you have a good ground, but as you suggested, I believe it is the ballast.
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Joseph Meehan

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What you have is essentially two fixtures built into one housing. Each operates independently, they're called "Circleline". The only connections you have, other than power are the four prong jacks that plug into the bulbs,so there is not much you can check.Your description does indicate an overheating ballast, as Jeff described. All fluorescent ballasts since the 70's are "T" rated and will turn off when they overheat, then turn back on after they cool. My suggestion would be to scrap the fixture and replace it with a straight tube fixture that uses electronic ballasts, which are much more reliable

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RBM wrote:

I agree with that suggestion and I might add that lamps will be less expensive and easier to find as well as offer more choices.
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So I've taken the cover off the fixture, and noticed that the ends on one of the tubes was kind of dark, so I decided to swap out both tubes with new circlite tubes...
I've also taken a look at the ballasts and they are electronic ballasts, as I said the fixture is not that old (maybe a couple of years)
After replacing both tubes I left the lights on for 2 hours to see if the ballast on the right would overheat, and shut off... no problems, lights stayed on, so I figured maybe it was just a bad tube...
Unfortunately I wasn't that lucky... a couple of hours later I turned the lights back on, and the one on the problem side came on, then went off, then came back on again... so I guess it wasn't the tubes...
Upon closer inspection I noticed that the ground wire on the fixture is not connected at all... and I think for these types of fixtures that they are supposed to be grounded aren't they? (The ballast actually has a note on it that says it must be grounded)
So now I'm thinking that maybe the cause of the problem is that the ficture is not grounded... kind of odd that this type of problem would show up after over a year of trouble free operation..
Does this now sound like a grounding problem?
I really like the fixture so I'd like to fix it if possible.... on the bright side the replacement cost for the fixture is $110. Might be worth replacing the whole thing, and keeping the old one for parts.
On Sun, 05 Mar 2006 15:02:16 GMT, "Joseph Meehan"

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Mark wrote: ..

Not having a good ground causes problems for fluorescent lamps. It makes them difficult to start. It also tends to create a safety hazard. I am not sure it exactly fits your described problems, but it certainly should be corrected, even if you are planning to replace the fixture, you should have a good ground.
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Joseph Meehan

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