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My bathroom has a fixture for twin 48" fluorescent bulbs. About every six months, the bulbs start to go bad. At first they will only come on about half way, and they flicker dimly for a few seconds before reaching full brightness. After a few weeks they just stay dim no matter how long they are on.

I have already replaced the ballast in this fixture, thinking that might help. No joy. I have replaced the bulbs twice a year for four years. I use the same bulbs in my other bathroom with no issues. Any suggestions?

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What else do you have on that circuit: like fans, etc? Anything with a motor can feed voltage spikes back into the circuit. – Niall C. Sep 3 '11 at 19:55
Is the condensation worse in this bathroom? – ChrisF Sep 3 '11 at 20:11
What kind of switch is on this fixture? Is it a digital switch, or one with possibly with a timer, dimmer, or a glowing backlight to help find the switch in the dark? – Karl Katzke Sep 3 '11 at 23:13
I'm not sure what else is on the circuit. I'll have to check. – Josh Earl Sep 4 '11 at 0:19
There is more condensation in this bathroom, but it doesn't seem excessive. – Josh Earl Sep 4 '11 at 0:20

Fixture ballast is bad. Time for new ones. Sorry!

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But I've already replaced it once, and it didn't stop the problem. Seems unlikely that I had two bad ballasts. – Josh Earl Sep 4 '11 at 0:14
are you sure you have the right kind of bulb? Some fixtures will not work well with the ES, energy saver reduced wattage bulbs or the Rapid start types. Check the spec for the type of bulb required. – shirlock homes Sep 4 '11 at 9:47

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