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
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
Any suggestions (besides ditching the lamp)?
Thanks for the clarification and the feedback. Yes, I was using "lamp" and
"fixture" interchangeably, in distinction from the "bulb". You're right, "bulb"
and "lamp" are closer in meaning; "fixture" is the entire unit from plug to bulb.
I opened the "brick"(held together by 4 small recessed screws)after sending my
inquiry and it appears to contain only a ballast with 2 wires at each end (this
conforms with the wiring diagram on the ballast label). The label identifies
the ballast as a Fu-chi brand PC-4526P-B 300 mA for PL-C 18w. Extensive work on
Google has failed to yield a useful hit for a replacement. The closest I saw
had 3 output wires and no dimensions were provided.
Turning the plug around makes no difference?
How about grounding the fixture? Flourescent tube lamps basically
require a "ground plane" to light properly - sometimes simply
"stroking" the tube when you power it on will make it light.
On 4/24/2010 8:32 PM, firstname.lastname@example.org wrote:
Thanks for the suggestion. The fixture has a polarized 2 prong plug. I've got
one of those handy-dandy circuit testers with 3 neon bulbs on 1 end and a 3
prong polarized plug on the other and it tells me that the circuit I'm using for
the fixture is properly grounded. I did try making nice to the glass tube while
it was attempting to light - no change. No, I don't think grounding is the
problem. Besides, the fixture worked just fine for 3 years plugged into the
OK, it seems unanimous here and on alt.engineering.electrical. If the problem
is the ballast, I'm ditching the fixture. Used every search engine I can think
of, including metabrowsers and I couldn't locate a replacement (if this were a
shop light I would have an embarrassment of riches deciding where to buy). Too
bad, I probably didn't use the fixture for more than about 300 hours. I think I
paid about $25 for the fixture on sale at an art supply store about 3 years ago.
Maybe that's why the item was on sale!
I think I'll stick to the old fashioned fixture that requires you to hold down
the on button while the filaments heat up, and then release the button. Those
seem to last forever (or as long as the switch does!)
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.
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.
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.
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