Two F4T5/CW bulbs failed

Users who are viewing this thread

Bill Arden

Computer Programmer
Messages
584
Reaction score
0
Points
0
Location
MN, USA
Website
www.billarden.com
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.
 
Last edited:

Jimbo

Plumber
Messages
8,918
Reaction score
18
Points
0
Location
San Diego, CA
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

Computer Programmer
Messages
584
Reaction score
0
Points
0
Location
MN, USA
Website
www.billarden.com
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

New Member
Messages
7
Reaction score
0
Points
0
Buy a new fixture

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

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks