Fluorescent Light Problem

OliLt

Member
I recently replaced the bulbs on a fluorescent light fixture located in my basement man cave. The fixture is 20+ years old. They were 40 watt u- shaped bulbs. The old bulbs were flickering, and noticeably dim. The end of the tubes showed black discoloration. The replacement bulbs were 34 watt high efficiency bulbs and specified a rapid start ballast which is what the fixture has.

The bulbs did not immediately illuminate after being switched on. They will sometimes illuminate after a few minutes, or with the slightest touch. Once on, they stay on, but after being shut off for a period of time, it"s the same pattern as before.

Is the ballast failing, or should I look for something else? Thanks in advance.
 
You said fixture was 20 years old it could be that where the bulbs fit into fixture may have a little oxidation or it could be ballast.
 
I have the same problem when the humidity in my basement is high. I run my dehumidifier and the lights come on instantly. I don"t have a problem in the winter when the humidity is low.
 
Aren't they annoying. I used to check sockets ,connections , change bulb - NG then change ballast. Now it seems you do everything and they still don't work right. Then you touch the lamp and they light .Next the ballasts will be obsolete.
 

my opinion only.. so..

using the new hE bulbs in and older fixture is a sure fire way of having starting problems.

I have gone to the 8 foot single pin fixtures in all my barns and unheated areas to solve the "no start" problem in damp and cold areas. I dumped all of the 4 foot fixtures.

There are fixtures that do better in cold and damp areas as most office and home fixtures are designed to fire at a minimum room temp of 65 degree with medium to low humidity.

again, just my opinion.

So try to find the old style bulbs, or change out fixtures as the ballast upgrades usually cost more than the new fixtures.
 
Make sure the fixture is grounded and the polarity of the black & white power wires is correct.

I have has slow / no start problems like you describe from both ground or reverse wiring faults.
 
(quoted from post at 12:30:04 09/14/14)
my opinion only.. so..

using the new hE bulbs in and older fixture is a sure fire way of having starting problems.

I have gone to the 8 foot single pin fixtures in all my barns and unheated areas to solve the "no start" problem in damp and cold areas. I dumped all of the 4 foot fixtures.

There are fixtures that do better in cold and damp areas as most office and home fixtures are designed to fire at a minimum room temp of 65 degree with medium to low humidity.

again, just my opinion.

So try to find the old style bulbs, or change out fixtures as the ballast upgrades usually cost more than the new fixtures.
too learned that swapping to a different tube with an old ballast does not always play together.
 
Does your light have a small Aluminum "starter" can, or is the neon bulb (inside the starter can) wired directly to the Ballast? Either way, you may have to replace that neon starter bulb, they get weak over time & extended usage.

:>)
 
(quoted from post at 15:35:47 09/14/14) I"ve always wondered why the Bulbs will come on IF You touch them with Your hand ??? Thanks.Larry
flourescense lights reguire a surge of high voltage electricity to intially fire up the bulbs. The drop of mercury in them will vaporize and help start the flow from end to end. changing bulb types will defeat this process. touching the bulb will actually pull the voltage towards your hand enough that the mercury will be electrified enough to turn to gas, allow the electricity to flow from end to end and thus making the neon, or other gases glow. Once the current flows from end to end, the voltage will drop to its "running" voltage. Some ballasts are so low on firing voltage that the require a metal ground down the bulb length to attract the voltage along its length to help make it fire. Older fixtures use the neon bulb as a switch to fire off the bulbs...and then switch to running voltages. New fixtures did it in the way the ballast was wound,, and even others have solid state inverters that fire the bulbs up.

The needed starting process is why some flouresence bulbs will not fire well in the cold or humid areas. New energy savings bulbs are very particular about the fixtures they are installed in.
 
New ballasts will solve the problem, just be sure to get the correct ones. The U tubes are probably T12 (refers to the diameter of the tube in eights of an inch, T12 = 12/8 = 1 1/2", T8 = 8/8 = 1", etc)

Check the label on the ballast. If you have T12 lamps, the ballast will say for T12 lamps. A T12 ballast will work with T8 lamps, but T8 ballast won't work with T12 lamps.
 
I am sure the fixture is wired correctly and grounded. This fixture does not use "starters". The bulbs I replaced worked fine, but started to flicker and go dim, thus they were replaced. The fixture is in a finished basement. I do run a dehumidifier to keep the humidity down. There are two other fixtures of the same type that are working just fine. Thanks for the replies.
 

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