I maintain F15T8 night lights at church. They are all on chokes with FS-2 starters and in a windowless room. One of them is EOL now, and the starter got stuck. However, when all the lights are out in the room except the two other F15T8 lamps, one end glows steady orange (expected) and the other flashes between orange and the normal tube colour at about 2Hz. If I turn on the regular lights farthest from this lamp, the flashing slows a bit. If I turn on all the lights, the flashing stops. It is not the starter that tries to open because the centre of the tube remains dark and the starter doesn't click. My first thought on this would be someting to do with the photoelectric effect.

I have seen loads of stuck starters over in Europe and a few here in North America, but I have never seen any do this.

For what it's worth, the tube is either GE or Sylvania F15T8/CW (but I think it is Sylvania) and the starter is Leviton, made in Costa Rica. A new tube and a new starter later today will revive this luminaire. Ah ! the beauty of good ol' magnetic switch start ! 

The electrode is just on the border for a discharge to form, and is oscillating around this point, i think for purely thermal reasons :

The filament heats and its resistance rises, voltage drop rises, arc across it strikes. The filament now gets less current heating it (some current s bypassing it through the discharge), it cools down, the resistance falls, voltage drop falls and the discharge goes out

Assuming the starter is really stuck, this may be photoelectric effect at work and may be voltage drop in the circuit when other lights are on (or rise if they are on the other phase of the supply). So lets test each one alone :

 - Light up 1 other lamp in the room, then make the room completely dark again by inserting a big cardboard box over the working lantren instead of switching it off, this way you only change the photoelectric conditions but not the electrical ones

 - Tap into the lighting circuit with a non light emitting appliance of comparable wattage (small hair dryer,...) and see if switching that on and off affects the behavior of the lamp with the stuck starter (take out of the lanterns the working lamps of starters as needed so you can play with the hair dryer without making light in the room)

And it is possible that the starter is actually working, just is so worn that instead of snap acting like it supposed to, it is arcing continuously near the point of closing the contact and is only slightly playing around that point. After testing the above first (to not disturb the fragile conditions present in the lantern) Try to move the starter to a good lamp and see what happens (if it appears stuck let it be a while and see if it suddely releases)

I seen that too happen with 36wT8's on 240v

One end orange and one end flashing between orange to white: One electrode deplated emitter and one electrode still have sufficient emitter. Real programmed start electronic ballasts, detects a rectification by this scenario and shutting down.
I've seem EOL TC-D 13W, flashing which one end is orange and one end is white.

Ash,

Thank you for the explanation. While it sounds like a good experiment, I cannot do it at this time. I need to fix this as soon as possible, and if not someone else will "try" to do it (and leave the stuck starter). I am also in the middle of a major cleanup in the organ, where a window blew apart in a storm last winter. I have to take out approximately a third of the 2000 pipes, and clean up the broken glass from the mechanism. Nevertheless, your reply satisfies my curiosity. Thanks again.

Sounds like big but enjoyable project there, so best wishes

When you replace the lamp and starter you can take the old ones for experimenting later as time permits. You might have to play with a variac (or lacking that a variable resistor made out of a space heater coil....) to tune to the same voltage at which the effects took place

Thank you.

No worries. The tube and starter have been replaced, but the old ones are saved for future experimentation when time permits.

F15's for night lights? I guess in a large room that would be little light, but the four F15T8's in my kitchen light up the room quite brightly. I've had both lamp & starter failures on those but never both at once. Interestingly, the original starters in two fixtures died before the first set of lamps did.

Have fun with the pipe organ. I've been doing that work in a theatre off and on, and even to this day, we find pipes that cipher, won't stay in tune or otherwise don't work quite right, take apart the pipes and sometimes the chests below them and find bits of plaster or whatever that had fallen into them from the theatre renovation many years ago. It must just take a while for the foreign object to lodge in just the wrong place!

@arcblue : the room is approximately 80 by 50 feet, and has no windows. The light switches are on one end only, so the night lights provide walk-through lighting to avoid bumping into things while getting to the switches.

For the pipe organ, it is a bit of fun, however once it is done, I hope I never have to do this again. I am doing the major cleanup, and the professionnals that come once a year will do the finer adjustments and the tuning. You are right, I occasionnally have to get in there to make emergency adjustments, usually just removing or deactivating the offending pipe until the pros visit the next year. I have never dismantled the windchests, nor do I intend to since I can't see how you would do it. Furthermore, I fear of not being able to put them back together correctly afterwards. Since it is in otherwise excellent shape, I don't want to do more damage than what is already there. It is a Casavant from Sainte-Hyacinthe.

For that one F15 is enough. How many are actually left on for full night ? And isnt it possible to install a 3 way switch to prevent the need to go in the dark ?

Yes, one F15 would be enough, but we're dealing with older people who don't necessarily have good eyesight, and the room is full of chairs most of the time. Wiring three way switches would work, however it would be expensive as the ceiling is finished (not a drop ceiling).

Is there any receptacle in reach which is not used, and is connected from the same spot as the lights ? That may be replaced with a switch and the other end of the cable run going to it reconnected as needed