I have a two-socket fluorescent lamp. Initially only one light tube was inserted and it worked fine. At some point, it started to go off seconds after being turned on. I thought the tube went bad, so I bought another F15T8. Surprisingly, if inserted alone, the new light tube would also go off right after being turned on. However, if I put both tubes in, BOTH would stay lit. The OFF switch then gets very hot (>100 C), which did not happen when I was able to use just a single tube. The lamp has two switches. The ON switch has to be kept pressed down for a few seconds until the light is turned on, while the OFF switch only needs to be pressed briefly.
How should I understand what happened here? Is the switch going bad and did that cause my first problem that a single light tube no longer stays lit? How could the switch get so hot?
Best Answer
A quick search of ballasts revealed electronic ballasts that support (2) F15T8.
Go straight to that, don't waste any time with old magnetic ballasts that buzz and flicker on a good day.
An instant-start ballast does that by shocking the tubes lit, but this wears the tubes faster. It typically needs 3 wires for a 2-tube setup, and they can run independently.
A rapid-start or programmed-start ballast makes use of the preheat coils in the tubes (automatically doing what the start switch did), causing an easier start. The rapid-start ballast is guessing. Both of them need typically 6 wires for 2 tubes, so you'd need to add wires to the neck conduit. They usually need both to be present/working.