Two F4T5/CW bulbs failed

[Bill Arden]

I bought three of these small 4W "under cabinet lights" (W-mart, Lights Of Am...) Model 7104

I am annoyed to say that one bulb failed after a month and another after two months.

The filament is open on one side with a dark color on the bulb.

Replacing the bulb fixed the light.

I am trying to figure out why the filament would fail as I had these lights are on all the time (24/7 path lights to let me leave off the main shop lights)

I am tempted to take one of the lights apart to see if they used a "continuous run" capacitor type circuit to heat the filament using the main Square wave output.

Edit: Yes it does use a "continuous run" filament circuit just like the cheep CF bulbs.
I'll hook it up to the scope to see if I can add a Neon bulb starter to it.

Edit again: Nope. The light needs the filament to be hot in order to keep it light.

[alternety]

Think LED.

I am not fond of LOA either.

[jimbo]

Philips rates an F4T5 at 6000 hours life, about 6 to 8 months@ 24/7. Rated life is the hours that ONE HALF of the population of bubs is expected to achieve. Half will be less, half more.

LOA makes crap, so I would not expect any of their bulbs to last all that long. They do also warrant their bulbs and fixtures, so you might give them a call.

[Bill Arden]

The start cap in the unit was 3.3nF.

This seems high since the start cap for a 13W CF is around 2.2nF

Testing shows that 1nF is enough to start even the older (darkened) bulb.

I wonder if they used the wrong capacitor ?

[lampman42]

Lights of America are crap fixtures, yes they are cheap but you get what you pay for. I would buy a new fixture.