Lamp only turn on when warm?


Old 08-23-12, 06:57 PM
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Join Date: Dec 2011
Location: Canada
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Lamp only turn on when warm?


When turning on the light switch in the laundry room, the lamp will come on only some of the time. It's random, so it will usually come on within a few tries if not the first time.

When it does eventually turn on, the bulb flickers and is about 50% of its full brightness.

Within minutes, the bulb will brighten up to 100% and if left on for several minutes, can be turned on and off with no problems at all.

If it is then turned off and left off for several minutes, then I need to go through the whole process again.

It sounds to me like if the bulbs are warmed up, then they will turn on no problem.

If the bulbs are cooled off, then they will not turn on immediately and will require several on/off switch attempts, then brighten to 50% and eventually full brightness.

The bulbs are florescent (the 4' long bright white types) and there are 4 slots, however only 2 bulbs are in use.

Does this sound like a light fixture problem or a problem at the switch box? (Also, I just replaced the light switch so it's brand new).

Thanks for any and all advice!
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Old 08-23-12, 07:16 PM
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Ballast and bulbs need to be matched. Your ballast may be only for 4 tube usage and is having issues with 2 of the tubes missing. The ballast may also be starting to fail or the tubes could be failing.

I would start with new tubes and see if the problem goes away.

High humidity can also cause hard starts.
Old 08-23-12, 08:25 PM
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Join Date: Dec 2011
Location: Canada
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I recall putting in 4 new bulbs a while back and the problem still persisted. but knowing that the problem is likely to do with the fixture/bulbs narrows down my problem. I was concerned that it was a problem at the switch box.

Infact, just last week, I would wiggle the on/off switch back and forth and sometimes it would make the lights come on full. I thought it was something loose in the switchbox, so i took out the switch, and replaced it with a new one. Now, wiggling it does nothing.

Does it still sound like it's likely a problem with the lamp fixture/bulbs ?
Old 08-24-12, 03:01 AM
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Is the grounding (bare) wire connected to the light's casing near where the ballasts are? Fluorescents like grounds. Quite often it is not connected properly. Check at your switch to make sure the grounding wire is attached to the green screw on the switch, also.

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