Fluorescent fixture problem

[Peter]

I've got a "no-name" clamp-on fluorescent fixture 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 fixture
where the clamp is located. The fixture 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 fixture (that
works normally) and when I swap the bulbs, the "good" fixture works perfectly
with the bulb from the fixture 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 fixture 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 fixture 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 fixture)?

P.S. Brick contains a Fu-chi ballast PC-4526P-B for PL-C 18W, 300 mA, with 2
wires at each end. No other components inside the "brick" case except for the 4
plastic insulating twist nuts that connect the ballast wires to the line cord at
one end and the cord to the base of the fixture at the other end. No foul
smells or scorch marks.

 

[[SMF]]

I've got a "no-name" clamp-on fluorescent fixture 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 fixture where the clamp is located. The fixture
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
fixture (that works normally) and when I swap the bulbs, the "good"
fixture works perfectly with the bulb from the fixture 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 fixture 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 fixture
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 fixture)?

P.S. Brick contains a Fu-chi ballast PC-4526P-B for PL-C 18W, 300 mA,
with 2 wires at each end. No other components inside the "brick" case
except for the 4 plastic insulating twist nuts that connect the ballast
wires to the line cord at one end and the cord to the base of the
fixture at the other end. No foul smells or scorch marks.

Verify that the ballast has line voltage. If not, troubleshoot the
cause.

Most likely the ballast tanked. I'm not sure what a replacement would
cost versus purchasing a new fixture, but that is your call if you
are attached to the fixture and they are no longer available.

 

[Peter]

REPLACE THE BALLAST

I AM PROTEUS

OK, it seems unanimous here and on alt.home.repair. 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'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!)

 

[Peter]

I've got a "no-name" clamp-on fluorescent fixture 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 fixture where the clamp is located. The fixture
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
fixture (that works normally) and when I swap the bulbs, the "good"
fixture works perfectly with the bulb from the fixture 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 fixture 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 fixture
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 fixture)?

P.S. Brick contains a Fu-chi ballast PC-4526P-B for PL-C 18W, 300 mA,
with 2 wires at each end. No other components inside the "brick" case
except for the 4 plastic insulating twist nuts that connect the ballast
wires to the line cord at one end and the cord to the base of the
fixture at the other end. No foul smells or scorch marks.

Follow-up:

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. Perhaps what I was
hearing was a starter buried in the depths of the bulb socket?

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?

 

[Peter]

The economics of "stuff" almost always says, "BUY NEW."

But I have noticed that some cheap fixtures (under $10 including lamp) use a
"starter" which, rather than being in a can, is just "hard wired" into
place. In one instanced I purchased a replacement starter (in a can),
took it out of the can, and by crimping the connections replaced the old,
bad starter.

I didn't have good crimping tools the the purpose so I will not do it again
but it's always a possibility.

Since the balast is just an inductor, it's likely to last a LONG time. The
starter, OTOH, is a gas tube. Often, when the main lamp goes out the
starter ends up trying to "start" a lamp that's not going anywhere. IOW:
the bad lamp takes the starter with it.

OK. Can I use the glow tube I take from an FS-2 starter (rated for 14, 15, and
20W bulbs)? I plan to cut the original wires off right at the glow tube bulb to
give me nice long leads, and solder, not crimp them to the leads of the new one.

 

[James Sweet]

OK. Can I use the glow tube I take from an FS-2 starter (rated for 14,
15, and 20W bulbs)? I plan to cut the original wires off right at the
glow tube bulb to give me nice long leads, and solder, not crimp them to
the leads of the new one.

Yeah that should work fine, these things are really not very critical.
The "tink tink" sound is the bimetal contact doing its thing in the
glowbottle, eventually either the contacts wear out or the gas fill
becomes trapped in metal sputtered from them.

If you prefer the old switch start type, you can replace the starter
with a simple momentary pushbutton, but the starters are cheap and
readily available.

Most of the new cheap fixtures are using electronic ballasts of
essentially the same design as used in disposable compact fluorescent bulbs.

 

[Peter]

HE CAN PROBABLY FIND A REPLACEMENT FROM .ANOTHER TYPE OF FIXTURE AS
YOU SUGGEST AND CANNABILIZE IT FOR THE BALLAST


I THINK HE ISN'T SEARCHING FOR THE REPLACEMENT PROPERLY
HENCE HE IS NOT FINDING IT
OR PERHAPS IT IS NOT THAT ESSENTIAL TO HIM

WHAT EVER THE CASE USER PETER

GOOD LUCK

I AM PROTEUS

Follow up:

I cannibalized an unused FS-2 starter I found in my "junk box" and wired in it's
glow bulb in place of the defective glow bulb I clipped out. To my surprise and
disappointment, when I replaced the CFL bulb, plugged in the fixture and turned
it on, the fixture and the glow bulb both continuously flickered. I waited
about 5-10 seconds to see if it would stabilze; it didn't. I turned off the
fixture, waited about 10 seconds, tried again with the same result. I then
added the capacitor from the FS-2 in parallel with the glow bulb (as it was
wired within the FS-2). Same behavior.

Should I assume that the glow bulb from the FS-2 is mismatched to this circuit
(although the CLF is 18W and the FS-2 is rated for 14, 15, and 20W bulbs), or
that something else is wrong in the circuit? Should I buy a starter with a
higher rating and try again with that?

 

[James Sweet]

Follow up:

I cannibalized an unused FS-2 starter I found in my "junk box" and wired
in it's glow bulb in place of the defective glow bulb I clipped out. To
my surprise and disappointment, when I replaced the CFL bulb, plugged in
the fixture and turned it on, the fixture and the glow bulb both
continuously flickered. I waited about 5-10 seconds to see if it would
stabilze; it didn't. I turned off the fixture, waited about 10 seconds,
tried again with the same result. I then added the capacitor from the
FS-2 in parallel with the glow bulb (as it was wired within the FS-2).
Same behavior.

Should I assume that the glow bulb from the FS-2 is mismatched to this
circuit (although the CLF is 18W and the FS-2 is rated for 14, 15, and
20W bulbs), or that something else is wrong in the circuit? Should I
buy a starter with a higher rating and try again with that?

It's possible that the tube voltage is higher than the breakdown voltage
of the glow starter. Try removing it entirely and touch the wires to the
glow starter together for a second or two and pull them apart, if the
tube lights normally then you just need a different glowbottle.

 

[Peter]

It's possible that the tube voltage is higher than the breakdown voltage
of the glow starter. Try removing it entirely and touch the wires to the
glow starter together for a second or two and pull them apart, if the
tube lights normally then you just need a different glowbottle.

Which model starter would you suggest I obtain? I've been singularly
unsuccessful on the web trying to find the specific electrical characteristics
of the many different starter models to decide. There are quite a few that are
supposed to be compatible with an 18W fluorescent lamp. Hint: The original
glowbottle was larger, both in length and in diameter than the one I
cannibalized from the FS-2.

 

[James Sweet]

Which model starter would you suggest I obtain? I've been singularly
unsuccessful on the web trying to find the specific electrical
characteristics of the many different starter models to decide. There
are quite a few that are supposed to be compatible with an 18W
fluorescent lamp. Hint: The original glowbottle was larger, both in
length and in diameter than the one I cannibalized from the FS-2.

You could measure the voltage. Just start it manually as I suggested,
then measure across the tube with a multimeter. What you get will likely
not be super accurate unless you have a true RMS meter, but it ought to
be close enough. Otherwise just try the next size up and see what
happens, starter for a 40W tube has a breakdown voltage of roughly 2x
that of the FS-2 starter.

 

[Peter]

You could measure the voltage. Just start it manually as I suggested,
then measure across the tube with a multimeter. What you get will likely
not be super accurate unless you have a true RMS meter, but it ought to
be close enough. Otherwise just try the next size up and see what
happens, starter for a 40W tube has a breakdown voltage of roughly 2x
that of the FS-2 starter.

I can't see how measuring the voltage would be useful because I cannot find any
starter electrical specifications (other than the wattage rating of the lamp
they are intended for).

However, your comment that a starter for a 40W tube shouldn't arc until the
voltage across the internal switch is about twice as much as for an FS-2 gives
me a great place to start. This weekend I'll pick up a starter rated for a 40W
tube, cannibalize its glow bulb, and substitute it for the one from the FS-2.

 

[James Sweet]

I can't see how measuring the voltage would be useful because I cannot
find any starter electrical specifications (other than the wattage
rating of the lamp they are intended for).

However, your comment that a starter for a 40W tube shouldn't arc until
the voltage across the internal switch is about twice as much as for an
FS-2 gives me a great place to start. This weekend I'll pick up a
starter rated for a 40W tube, cannibalize its glow bulb, and substitute
it for the one from the FS-2.

Well I guess you'd have to measure the breakdown voltage of the starter
as well in order to characterize them. In a nutshell though, assuming
North America, 20W and smaller lamps are designed to run from a 120V
line with a simple choke to limit current, while larger lamps require an
autotransformer ballast to step up the voltage. In Europe, the larger
lamps also use a choke as the 240V line is sufficient to light the tube.

The starter has to be matched roughly to the sustaining voltage of the
tube. If it is too low, the gas in the starter will break down even
after the tube has struck, and if it's too high the gas will never break
down at all and nothing will happen. To work, the breakdown voltage must
be lower than the open circuit voltage available from the ballast, but
higher than the worst case sustaining voltage of the tube.

 

[James Sweet]

start it manually as I suggested,
Sorry, sport.

But for the purpose, the definitely DON'T want a "true TMS" meter. If
anything, you want a meter that respons to PEAK voltage. Most cheap VOMs
do just that.

It's the PEAK voltage that causs the tube to "fire."

My thoughts on true RMS came from past experimenting with HID ballast
design where both the RMS and peak values are important, some lamp types
are picky about the crest factor and if either the peak or RMS current
values are out of line lamp life can be dramatically reduced and in some
cases there is the risk of a violent failure. There is far less to worry
about with fluorescent lamps though.

Most cheap VOMs are averaging, their response to non-sinusoidal
waveforms (which you'll have across a discharge lamp) and frequencies
other than 60Hz (such as electronic ballasts) is unpredictable and are
not the peak voltage either. Many inexpensive electronic ballasts
produce an output that varies widely in frequency depending on lamp
voltage and other factors so if you try to measure it with a cheap meter
you get inconsistent results, and values measured with one cheap meter
may be much different than the same measured with a different meter. A
scope or power analyzer would be ideal, but in reality with this
particular case you are better off just trying something, either it will
work or it won't. Glowbottle starters and fluorescent lamps are not
precision devices, their rated characteristics are approximate and vary
throughout life. You have to be careful using ballasts and lamps in
unsanctioned combinations but substituting a starter is unlikely to
cause any harm.

It's worth mentioning too that if you try to measure anything, don't
connect the meter until after the lamp is lit. Choke ballasts can
generate spikes big enough to damage digital meters while starting the lamp.