Fluorescent light bulb or ballast?

I flicked the light switch in the bathroom and only one of the 4 fluorescent light bulbs came on. After about a minute or so, the other three came on. I turned it off and let it sit for 10-15 minutes and tried it again. All 4 came right on.
Should I replace all 4 bulbs or is it likely the ballast (is that the right word) that is going bad?
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On 2/20/2012 6:11 PM, Jennifer Murphy wrote:

If these are T-8 fluorescent lamps, there is probably only one ballast. The problem is likely the lamp or it's connection at the socket.
If these are T-12 fluorescent lamps, there are two ballasts. The problem is still more likely the lamp or it's connection at the socket.
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On 2/20/2012 6:11 PM, Jennifer Murphy wrote:

Sorry, I read it, or at least interpreted it backwards. (dyslexia or something) That sounds like something flaky with an electronic ballast.(T-8) Doesn't seem likely to occur with a pair of magnetic ballasts (T-12) May just be an anomaly, see if they continue to work properly.
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On 2/20/2012 5:11 PM, Jennifer Murphy wrote:

What was the temperature in your bathroom? If it was cold in there, the lights may take a while to come on. Someone may have already mentioned wiggling the bulbs because in a bathroom exposure to a lot of moisture could have cause a bit of corrosion on the bulb contacts.
TDD
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On Mon, 20 Feb 2012 20:05:50 -0600, The Daring Dufas

The house is in south Florida, so it's warm and humid. Plus it's a bathroom without good ventilation. We were out for several hours. When we got back, the lights went right on.
Tomorrow, I'll remove the bulbs and check the contacts for corrosion. I suspect the bulbs are fairly old. It's my mom's house, and she is not sure when they were last replaced.
Thanks
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wrote:

Jennifer,
Remove all four tubes. With a slightly damp rag, wipe down all the tubes to get any accumulated dirt off the glass and the ends. Dry thoroughly and put the tubes back. Not if any have fairly blackened glass at the ends of the tubes. Replace the tubes. See what happens. If one light lights right away, note that tube and mark it somehow. Switch the good tube with any of the other three tubes. See what happens when you turn the fisture on. Does the good tunbe light, or does the replacement tube light. If the replacement tube lights, the ballast is liekly to be bad.. IF the good tube still lights, the other tubes is probably bad.
The above suggestions are right on especially the one about cleaning the tubes.
In damp, humid environments a film of moisture and dirt can "short-circuit" the electrostatic starting system of rapid-start lamps especially if the lamps are the T12 type on electromagnetic ballasts.
The simple solution is to clean the lamps. I use Windex and then rinse and dry the lamps. You can check the lamp pins for corrosion at the same time.
When such lamps are manufactured, they are sprayed with a "dry film" coating so as to minimize starting problems. When you rinse the lamps, you can check to see if the coating is working by looking at the lamp and seeing if the water forms beads and drops rather than a continuous film.
In any case, it's a simple way to check your fixture. If cleaning doesn't work, then the likely culprit is a lamp or lamps near the end of life. Ballasts can fail, but they usually work or they don't. Since you said that the lamp came on after a while, a failed ballast is not the problem.
Tomsic
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On Mon, 20 Feb 2012 19:58:45 -0800 (PST), "hr(bob) snipped-for-privacy@att.net"

Good plan for isolating the failing component, thanks.
I did as you suggested. I didn't see anything that looked like corrosion. When I put them back, all 4 lit up like they always have. Maybe something was loose or I knocked off a little dirt.
Thanks for the help.
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Strange as it sounds it may be the bulb that is coming on is the bad one.
Jimmie
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