BulbCollector Forums
BULB DISCUSSION BOARDS => Modern Electric Lighting => Topic started by: mr_big on October 06, 2005, 01:14:36 pm
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I had a feit electric 24 inch fluorescent running on a preheat ballast last night I noticed that it was flickeing a little I waited about an hour and then it just kept shutting down but then restarting I know this is normal for end of lamp life on a preheat ballast but the ends of the lamp where not black
Instead when it shut off one end was glowing orange and the other was glowing the normal color
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One orange, one white electrode - dead tube, Emitter one one of the electrodes has expired.
As for the blackening issue, not *always* what happens. Especially in the larger tubes where electrode shields are often used to prevent the sputtered electrode material from being able to contaminate the phosphor coating inside the tube.
Just make sure that you remove the starter from that lamp (or even better, the lamp itself), as this cycling behaviour stresses the ballast - especially if the starter contacts stick shut (which they probably will do eventually if it keeps cycling). And sitting like that will almost certainly overheat the ballast. Probably won't actually damage it (most modern ones have built in overheat protection anyway) - but obviously ain't good for it at all, and could very possibly present a fire hazard.
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And, when you replace the tube, consider fitting an electronic starter (sometimes referred to as a pulse starter). The tube life will be extended, and should a tube fail whilst unattended, the risks described above - i.e. stress to the ballast - will be eliminated as the circuit is cut out automatically with a failed lamp.