In article ,
Jason writes:
Graham. wrote:


I have dissected some recently. The Philips 11W ones were completely
dead, but the tubes themselves showed no discolouration at the ends,
so I took a look at the ballasts
The reservoir capacitors have gone high ESR, and are bulging
at the top.
http://myweb.tiscali.co.uk/infoweb/philips_cfl.jpg

In the lower one, failure appears to be due to the switching
transistor having blown up.

That has happened to all the bulbs I've ever taken apart too. Except for one
where the PCB tracks burned out.

Some designs deliberately burn out a track or fusible resistor
to prevent continued operation when the tube filaments are worn
out. (Continuing to run a dead tube is a fire risk as the tube
ends get very much hotter if the ballast lets it run in cold
cathode mode after the filament coatings have failed.)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]