Peter wrote:
I've got a "no-name" clamp-on fluorescent lamp that no longer starts
when the rocker switch is snapped from the off to the on position. The
lamp has a polarized plug with an in-line black "brick" 7 1/2" x 2 1/2"
x 1 3/8" that has the code "G0138" stamped above the code "GG10051F" on
the bottom but no other markings. The 2 conductor cord from the brick
goes to the base of the lamp where the clamp is located. The lamp uses
a single 18W 4 pin double tube bulb with code G24q-2.

I'm sure that the bulb is good because I have a second, identical lamp
(that works normally) and when I swap the bulbs, the "good" lamp works
perfectly with the bulb from the lamp that is not working. I also have
a brand new spare bulb that I've tried in the non-functional fixture and
it too fails to light in the bad fixture.

The problem started spontaneously with no earlier indication of
problems. Normally, when the lamp is turned on, there are a few quick
white flashes in the bulb and the bulb lights and glows steadily. The
behavior I observe is that when I snap the rocker switch to on, the bulb
either has one quick white flash but then I only see the heaters glowing
in each of the two tubes, or there is no white flash at all, and all I
see is the glow of the heater filaments. I've tried plugging the lamp
into another outlet in case the problem was related to grounding (I've
read that these quick start bulbs need their circuits and fixtures to be
grounded to work properly) but it did not help. The "brick" has always
been entirely quiet and never got particularly warm, and that has not
changed.

Any suggestions (besides ditching the lamp)?

Someone mentioned this already and got me thinking. The older
fixtures like yours have a replaceable starter that is easily
accessed. For cost savings, your fixture may have a starter
hard wired into the fixture itself. Turn on one of the good
fixtures and listen closely the part of the fixture on either
end of the lamp, if you hear a couple of clicks that may have
a sound like "tink", it could be a starter. You could easily
disassemble the fixture and take the guts from a standard
starter and use the parts to replace what's in there. There
is also the possibility that instead of a conventional starter,
there could be a thermistor like what is in an old TV degaussing
circuit. You won't know unless you take it apart.

TDD