Mr_Bill wrote:
I have under-cabinet fluorescent lights. Two
light fixures in parallel, wired to one single pole switch.
Each light fixture consists of 2 13W tubes, driven
by a "ballast". (So, the total rig consists of 1 switch,
2 ballasts, and 4 fluorescent tubes).

Today, 3 out of the 4 tubes went dark. Long story
short, all is well after I replaced only *one* tube. That
one bad tube had caused both tubes in 1 fixture to
go dark, *and* one tube in the neighboring fixture. (?!)

Anybody know what's going on?

Bill


Pretty sure!