The most suspected item on CFL bulb circuits

Thread Starter


Joined Oct 30, 2008
Hi guys; what is the most suspected (faulty) item you found when you were repairing CFL bulb circuits? What is the quick way of fading faulty item? :confused:

CFL, i mean "Compact fluorescent lamp"

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Joined Feb 4, 2008
The most suspected items is the starter of the fluorescent bulb and then the balast.


Joined Dec 20, 2007
I think a CFL is a Compact Fluorescent Light bulb. They have a simple rectifier and 40kHz inverter. The ones in Canada and in the USA don't have a "starter". The 40kHz inverter provides plenty of voltage to start them.

I have never seen anybody fix them because they are sealed and cost almost nothing.
I broke open two that had their glass break. I salvaged some ferrite inductors and transformers. There are some high voltage Mosfets and capacitors in there that I probably will never use.


Joined Apr 20, 2004
I've had two fail from what appeared to be the filament overheating. The potting material was very brown at the point where one leg went in, plus the tube looked overheated.

Don't know if you can make a general case from that, nor does it seem to be possible to make a repair for less than 4 X the replacement cost.


Joined Jul 17, 2007
I think there's a tendency for the manufacturers to want them to run a bit "hotter" than they should; you get more light out of them, but they don't last as long.

Besides, they're trying to spec these things at the minimums to save manufacturing costs.

The average person won't pay any attention to how long a lightbulb lasts - but when one burns out, they'll go to the store and buy the cheapest that they can find.


Joined Jul 5, 2006
Looking into the frequency of failure of a component in a circuit makes sense for a manufacturer attempting to increase reliability, but not necessarily for an end user considering an individual failure. Examination of the failed circuit would inform you more.

I don't know what the CFL supply and cost situation is in Sri Lanka, but here in the US it certainly makes no economic sense to attempt repair of a failed CFL when you can buy them at a subsidized price of less than US$2. As an educational venture or to satisfy curiosity, however...

Have fun.