Naked Science Forum
General Science => General Science => Topic started by: justinhood on 26/12/2009 23:00:16
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I am trying to resolve my flashing fluorescent tube problem. The light does not have a started but has a pack which I believe lowers voltage and powers the start up. The off switch is mechanical IE a pull chord. I guess there is some leakage of current which continuously charges the pack which when charged tries to start the lamps causing a very fast flicker or flash. It happens every minute or so but is so dull you cannot see it in the day time only at night.
How do I solve it and is it dangerous?
PS mirror is on a 5 amp rcd as in a bathroom.
many thanks
Justin
[MOD EDIT: JUSTIN - CAN YOU PLEASE EDIT YOUR POST TITLE TO RE-PHRASE IT AS A SELF-CONTAINED, MEANINGFUL QUESTION, IN-LINE WITH FORUM POLICY. THANKS. CHRIS]
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Flashing fluorescent lights are not dangerous, they are simply wearing out. In some cases the electronic circuitry might be failing, but in my experience the result is the tube itself will not light up at all. Tubes that are going bad will increase their flickering over time. This would be a dead givaway to simply replace the tube.
My suggestion is to remove the offending tube and replace it with one from elsewhere in the house and observe the results. If you do not have another one in the house, buy one and install it. If it still flickers, replace the fixture.
In some rare instances the 'Starter' element might be faulty. This piece is readily identifiable as a small metalic cylindar that sticks out of the fixture near the end of the tube. I have not seen this starter system for sale in decades, however. They tend to make a clicking sound when the light is turned on.
I hope this is of some help in your decision.
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Thank you for your reply. I have changed the tubes and they still flash. It does not have a starter but has a type of power pack? I have been told it is smething to do with current trickeling through and when it builds up it tries to start the tubes resulting in a quick flash?
J
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fluroscent tubes (http://www.naturalhandyman.com/iip/infelectrical/inffluor.html)
Could it be the ballast?
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Justin, I'm confused (which is not very unusual!).
Are you saying the thing is flashing periodically, even when it's turned off, or are you saying it's only flashing when it's supposed to be turned on?
If it's the first condition, then I think the switch is faulty and current is "leaking" through it. The switch needs to be replaced.
If it's the second condition, and you have already replaced the tubes, then it's sounds like the ballast unit is defective. (Unless the light is rather old, it's unlikely to have a replaceable starter.) The bad news is, it's not that easy to replace the ballast, and you would have to find one with the right specifications.
Unless it's a very expensive light fixture, it's probably not worth having it repaired.
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This old thread may help:
http://www.thenakedscientists.com/forum/index.php?topic=24193.0
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I am trying to resolve my flashing fluorescent tube problem. The light does not have a started but has a pack which I believe lowers voltage and powers the start up. The off switch is mechanical IE a pull chord. I guess there is some leakage of current which continuously charges the pack which when charged tries to start the lamps causing a very fast flicker or flash. It happens every minute or so but is so dull you cannot see it in the day time only at night.
How do I solve it and is it dangerous?
PS mirror is on a 5 amp rcd as in a bathroom.
many thanks
Justin
[MOD EDIT: JUSTIN - CAN YOU PLEASE EDIT YOUR POST TITLE TO RE-PHRASE IT AS A SELF-CONTAINED, MEANINGFUL QUESTION, IN-LINE WITH FORUM POLICY. THANKS. CHRIS]
Hi Justin.. I know some small things about older mirrored florescent tubes and the ballast was quite small and easy to change.. some of the larger shop light lighting have these large rectangular ballast that are generally like a big black box housed in the ceiling mount Harder to replace and about 79 t0 a hundred bucks per pop depending on where you live.. they are easy to get.Most hardware supplies crry them..
I suspect if it is an older mirror type florecent like mine...one on each side of my mirror then each bulb will have a ballast and they are round small cylindric barrels with 1 or two prongs on each end, which goes up into the hole and turns into place much like the tube...
I will post a picture hang on..
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I suspect if it is an older mirror type florecent like mine...one on each side of my mirror then each bulb will have a ballast and they are round small cylindric barrels with 1 or two prongs on each end, which goes up into the hole and turns into place much like the tube...
I will post a picture hang on..
Karen, those sound a lot like starters, not ballasts. But if it is an old fixture, it likely will have starters.
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They are starters and say that on them but at our hardware store they have them listed as ballast for lights of that time period...
I will post a small starter for the mirror of this period... I am with you though..that was the only way I was able to find the little barrel starter..LOL
The Ballast on newer lights are quite big.. do you think my old mirror and Justin's may have a larger ballast that I am not aware of?
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This is the mirror vanity Justin , Is yours this old?
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Sorry that took so long.. I am having connection issues...
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Yes. I think your light fittings will have a thing called a "choke ballast" in them. It's probably under the cover, so you won't be able to see it unless you take the fixture apart, which I don't recommend [:D]
The starter is a sort of delay switch that passes current through the elements at each end of the tube to heat them up so the tube can "start" to do its thing. The ballast limits the current flow between the ends of the tube while it's putting out light.
More modern fittings combine both functions into a single "electronic ballast" about which I know little!