Dave wrote:
First time I've ever bought one of these LL lamps (sad,,, sad). Anyway, It's 20W
equiv. light of 100W and has three long U shaped tubes. When switched on, only
two of the tubes light up (takes about 1 minute to reach full brilliance). But
it takes a few minutes longer before the third tube shows any light at all! Is
this normal operation?
tia

It's all one tube. What you describe is not uncommon if the lamp
hasn't been used for a while or is quite cold. There's no light
from part of the tube (the middle normally) as there's no mercury
vapour there. It will diffuse down as the tube warms up.

--
Andrew Gabriel