Electronic ballast for for 40 watts florescent tubes

[Anirvan]

Recently, I had to replace my electronic ballast of my study room florescent tubelight (Phillips make). The older one when used the last time had made the tube to only flash once before going dead. I noticed that the tubelight's filament on one side was still glowing even after I switched off the power thinking that the tubelight may blast. Later on I checked the defective ballast's all components and found all to be Ok. So I have a question that why did it burnt out one of the tubelight's filament and failed if all its components are ok ?

 

[JonSnell Electronic]

The Philips tube has probably exhausted itself and if it doesn't strike, will glow at one end.

 

[patagonia]

Dont like fluoresent tubes for a study room, the flickering they have is tiring for the eyes, it might be a good idea to change all to a warm led alternative.