On 4/24/2010 12:30 PM, The Daring Dufas wrote:
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?

If you get a standard starter look at the contact end and if it has a
aluminum can, you can bend the tabs back and remove the guts and there
will be the silvered bulb with a capacitor in parallel with it. Some
of the new starters are in a plastic can but you can open them too.
The glow tube incorporates a switch which is normally open. When power
is applied a glow discharge takes place which heats a bimetal contact. A
second or so later, the contacts close providing current to the
fluorescent filaments. Since the glow is extinguished, there is no
longer any heating of the bimetal and the contacts open. The inductive
kick generated at the instant of opening triggers the main discharge in
the fluorescent tube. If the contacts open at a bad time - current near
zero, there isn't enough inductive kick and the process repeats. That's
the tink, tink sound you hear.

http://home.howstuffworks.com/question337.htm

TDD
Can I use the glow tube from an FS-2 starter (rated for 14, 15, and 20W bulbs)
or do you recommend a different standard starter? Also, my socket does not seem
to be using the capacitor; I assume that I should ignore that component and just
replace the defective glow tube with the new one.