I have a bathroom mirror with two 18" 15W fluorescent tubes inside,
similar to http://www.argos.co.uk/static/Product/partNumber/4327411.htm
A couple of days ago, one of the tubes didn't come on. I took the front
off and swapped the tubes over in order to try to ascertain whether the
problem was with the tube itself, or with whatever was powering it.
The effect of swapping the tubes was that *neither*
of them now works -
and they continued not to work when I swapped them back!
The tubes are driven by some sort of electronic ballast which has mains
in at the top and 8 outputs at the bottom - 2 for each end of each tube.
Do any of you have any experience of these things? If a tube fails, can
that kill its side of the ballast? Could swapping the tubes have killed
the other side, too?
Is there any way that I can test a tube by using a multi-meter? I've
tried measuring DC resistance across the pins. On both tubes, there
appears to be virtually no resistance between the two pins at the one
end and infinite resistance between the pins at the other end, but I'm
not sure what - if anything - that tells me!
Would the best plan be to replace the ballast and both tubes? I can't
find an identical ballast but this one is similar and would probably fit:
This is 2 x 18w rather than 2 x 15w, but I could get this plus 2 x 18
watt tubes for about £20 - which is a lot cheaper than replacing the
whole thing for £70.
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