On Sat, 24 Apr 2010 20:10:54 -0500, The Daring Dufas
wrote:

wrote:
On Sat, 24 Apr 2010 11:57:29 -0400, Peter wrote:

On 4/24/2010 11:12 AM, The Daring Dufas wrote:
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
The fixture always did start with a "tink" "tink" "tink" each one corresponding
to a flash of the bulb. I don't hear that noise at all now.

I was able to pull off the rotating shade, unscrew the bulb socket, pull it out
about 2", and observe a 1" glass bulb that looks almost like a neon bulb with an
opaque mercury-like metallic coating on the inside of the glass bulb. There are
2 wires coming out of the base of this little bulb, 1 connected to the black,
and the other to the white power wires that enter the base of the socket.
Perhaps this is the hard-wired starter? There are no markings on it at all. I
reattached the bulb, plugged in the fixture, and turn it on while observing the
little glass bulb. Nothing at all; no glow, no sparks, no "tink" "tink" "tink".
What do I replace it with?
Try an NE2 bulb? That's what used to be in the old starters.

ERRRRRRR! Wrong! I would suggest you find an old florescent starter
and take it apart, carefully break the glass off the silvered bulb
and you will find a heat activated bi-metal switch. A little searching
of The Interweb will help you learn how it works.

TDD
You are right - I was wrong - it is not a simple NE2 bulb - Long time
since starters were common, and as a kid we used to canibalize
starters to use the glow tube in place of NE2 bulbs for things like
oscillators.