I have a 3 lamp fixture which used T-5 (the thin ones) tubes in a ceiling fixture. It has been very unreliable. I had the first on for 6 months and the lamps started to fail. Sometimes it would light 1 tube, or 2 and sometimes all 3 would light and 1 or 2 would go out after 30 minutes or an hour. I eventually took it back to HomeD and they gave me a new one even though the 90 warranty had expired.
Well, a few months later and the new fixture is doing it again. I have examined the contacts and connections and removed and replaced the lamps. Sometimes moving the lamps works, sometimes not. I am sure that I don't have a second bad fixture, but who knows. I am sure that they would not replace it again. The manager told me that there is not a high rate of return on these fixtures.
What gives? I might have a few hundred hours on the thing, and it gets, I am guessing, 8 or 10 turn no/off cycles a day. Do these tubes have a very short life? (they are quite expensive, BTW, $8-10 each). The fixture has 2 ballasts (electronic), one for 1 tube and the other servicing 2 tubes.
I AM GOING NUTS!
Some of the cheap fixtures will run the start heater filament at a high voltage and burn it out. If that happens the tube will be black at the ends normally.
If the pins are clean and a connection is not a problem, Then you can turn the tube around and maybe get a bit more of life out of it.
I would start by cleaning the pins on the lamps and their holder.
Last edited by DonL; 10-19-2013 at 09:47 AM.
Theory only works perfect in a vacuum.