I have been using a lot of magnetic CFLs (PL-S and PL-C type, usually 13w, and 15w capsule (2-U tubes) in my home over the years, and generally they are very reliable and long-lasting, often better than their electronic counterparts. But lately I’ve been having trouble with quad PL-C or 2-U type tubes when they are in enclosed fixtures or in capsule bulbs.

When they are new, they start normally and are fairly bright when started,  but after a few dozen hours of using them normally, they have difficulty starting and finally come on dim and flickering. In other words, they blink for about 10 seconds before they start, then have trouble staying lit, flickering and flashing and finally stay lit but are dim and flicker until they get a bit warmed up then work fine and will start normally if still warm. But once cooled down, they act again like they are starting at below freezing temperatures, except this occurs at room temperature. I haven’t had this experience in the past with similar lamps. This is happening with newer PL-C 13w tubes in enclosed jar fixtures, in Reflector CFLs and also some NOS globe CFLs in open fixtures.

They don’t seem to be overheating in use, but it’s like the mercury isn’t available once they’ve cooled down and then they cannot start normally. It makes these lamps impossible to use at home as it takes the lights way too long to come on.. Obviously I love these bulbs and don’t want to convert to LED but this is unacceptable unless a light remains on constantly.

Anyone know what’s going on here? Mercury starvation? I know with enclosed spirals, over time they start dimmer and more mercury starved, so dim and often pink they produce practically no light when first turned on. But this is not something I’ve experienced with older style CFLs before. Maybe from too long in storage, or they were being manufactured differently?

You say ‘newer’, could be the same phenomenon with all low and high pressure discharge lamps, whereas the manufacturers KNOW their becoming obsolete so quality is let slip greatly, as pretty soon there will be no market for them?
SOX went the same way, and a couple of years before Thorn Lightings Melton Road works shut down, the last batches of GE SOX suffered the same fate as the Osram branded ones that came out of Hamilton, (early blackening of the infrared coating)!, as if they also gave up on quality for a dying product!

It also explains why LED are constantly getting better and better, as their the ‘in thing’ that is earning lighting company’s the most money, (why invest in making the current PL fluorescent better, when their heading for the ban list anyway)?

Have you tried one on HF gear?, as the electronics in the circuit should deal with anomalies like you describe?