From: "TKM" 
Newsgroups: misc.consumers.house
Subject: Re: maddening fluorescent overhead problem
Date: Tue, 15 Mar 2005 14:17:33 GMT


 wrote in message 
news:1110673712.581527.188360@l41g2000cwc.googlegroups.com...
> actually i live in an apt but i was hoping to tap into expertise here.
> the kitchen has a double-fluorescent overhead light.
>
> something is wrong other than the tubes, which are new.  if you switch
> on the light, initially they both burn, but then they flicker madly,
> almost like disco strobe lights, then the same one in the pair always
> goes out. after a couple HOURS -- based on experiment of keeping them
> on -- both lights resume normal operation.
>
> what is this? a starter? a ballast? whatever? thanks.
>
>
> p.s. the apt maintenance people came by 3 days in a row futzing around,
> but whatever they did, it hasn't worked.

You don't say what kind of fluorescent tubes are involved, but if they are 
the usual 4-foot type and have 2 pins at each end, then there are two things 
to check before replacing parts:

1.  Are the new tubes  the same type as the old ones?  For example, if the 
old tubes were 1.5 inches in diameter (so-called T12 tubes) and they were 
replaced by tubes 1 inch in diameter (T8 tubes), that could cause the 
problems that you are seeing.  The way to check that is to take off the 
metal piece that covers the ballast and look on the ballast label.  It lists 
the tube types that the ballast is designed to operate.  Match those tube 
types with the tube type marked on the tube itself.  For example, if the 
ballast label says that it is intended fror "F40T12" tubes, check the tube 
to see if "F40T12" is printed on one end.

2.   It could be that one or more of the pins at the end of the tube is not 
making electrical contact with the socket.  Fortunately, that's easy to 
check.  Switch off the fixture.  Remove the tubes one at a time and then 
replace them making sure that all 4 pins seat properly into the sockets.  It 
takes a quarter turn of the tube to lock them into place and when that's 
done, you should be able to see the pin making contact with the metal inside 
the socket.   I've seen tubes that seem to be a bit short (or maybe the 
sockets have been spaced too far apart) so you have to place the tube in the 
sockets very carefully.

TKM