fluorescent light problem

[Michael]

Two fluorescent fixtures in two bathrooms of my mother's house seem to
be possessed. Both are
integral parts of medicine cabinets and are 20 years old, as is the
house. Eight or nine
years ago one light started acting up: when the wall switch was flipped
ON, sometimes the tube would come on only dimly while other times it
would come on fully. When ON dimly, the tube could be made to come on
fully by touching a finger to the metal cabinet. New tubes exhibited
the same symptom and behavior. Two years ago I replaced the ballast and
that seemed to fix the problem; it didn't fail to fully fire in several
dozen ON/OFFs. But last winter that same fixture started acting up in
the same old way, and last week a second, identical fixture in another
bathroom followed suit. Mom is on the war path, demands satisfaction.
But I don't know what else I can do. Ripping out the two medicine
cabinets and installing ones that have incandescent lights is definitely
a non-starter.

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground? I'm in NY and fixtures are in NH, so
I can't check what the actual case is.

Finally, is there a more appropriate NG for this query?

Tnx,
Michael

 

[Charles Schuler]

"Michael" <NoSpam@this.addy> wrote in message
news:3F1C3304.15C50AD5@this.addy...

Two fluorescent fixtures in two bathrooms of my mother's house seem to
be possessed. Both are
integral parts of medicine cabinets and are 20 years old, as is the
house. Eight or nine
years ago one light started acting up: when the wall switch was flipped
ON, sometimes the tube would come on only dimly while other times it
would come on fully. When ON dimly, the tube could be made to come on
fully by touching a finger to the metal cabinet. New tubes exhibited
the same symptom and behavior. Two years ago I replaced the ballast and
that seemed to fix the problem; it didn't fail to fully fire in several
dozen ON/OFFs. But last winter that same fixture started acting up in
the same old way, and last week a second, identical fixture in another
bathroom followed suit. Mom is on the war path, demands satisfaction.
But I don't know what else I can do. Ripping out the two medicine
cabinets and installing ones that have incandescent lights is definitely
a non-starter.

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground? I'm in NY and fixtures are in NH, so
I can't check what the actual case is.

I can't answer all your questions but can suggest that corrosion of the
contacts is a possibility. Also, I have found that the contacts lose their
tension. Touching the cabinet? That's strange ... I'll be curious to see
if you get any replies about that!

 

[Tom Biasi]

"Michael" <NoSpam@this.addy> wrote in message
news:3F1C3304.15C50AD5@this.addy...

Two fluorescent fixtures in two bathrooms of my mother's house seem to
be possessed. Both are
integral parts of medicine cabinets and are 20 years old, as is the
house. Eight or nine
years ago one light started acting up: when the wall switch was flipped
ON, sometimes the tube would come on only dimly while other times it
would come on fully. When ON dimly, the tube could be made to come on
fully by touching a finger to the metal cabinet. New tubes exhibited
the same symptom and behavior. Two years ago I replaced the ballast and
that seemed to fix the problem; it didn't fail to fully fire in several
dozen ON/OFFs. But last winter that same fixture started acting up in
the same old way, and last week a second, identical fixture in another
bathroom followed suit. Mom is on the war path, demands satisfaction.
But I don't know what else I can do. Ripping out the two medicine
cabinets and installing ones that have incandescent lights is definitely
a non-starter.

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground? I'm in NY and fixtures are in NH, so
I can't check what the actual case is.

Finally, is there a more appropriate NG for this query?

Tnx,
Michael

Hi Michael,
Since its the bathroom I would bet on the corroded contacts.
Sometimes even the slightest coupling to ground or AC Hum will cause a
borderline lite to come on.
Next time you see one flickering run your finger up and down the tube and
see what happens.
regards,
Tom

 

[Sir Charles W. Shults III]

It is possible you have a poor ground or neutral connection.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip

 

[Harry Conover]

Michael <NoSpam@this.addy> wrote in message news:<3F1C3304.15C50AD5@this.addy>...

Two fluorescent fixtures in two bathrooms of my mother's house seem to
be possessed. Both are
integral parts of medicine cabinets and are 20 years old, as is the
house. Eight or nine
years ago one light started acting up: when the wall switch was flipped
ON, sometimes the tube would come on only dimly while other times it
would come on fully. When ON dimly, the tube could be made to come on
fully by touching a finger to the metal cabinet. New tubes exhibited
the same symptom and behavior. Two years ago I replaced the ballast and
that seemed to fix the problem; it didn't fail to fully fire in several
dozen ON/OFFs. But last winter that same fixture started acting up in
the same old way, and last week a second, identical fixture in another
bathroom followed suit. Mom is on the war path, demands satisfaction.
But I don't know what else I can do. Ripping out the two medicine
cabinets and installing ones that have incandescent lights is definitely
a non-starter.

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground? I'm in NY and fixtures are in NH, so
I can't check what the actual case is.

Finally, is there a more appropriate NG for this query?

Tnx,
Michael

Michael, the symptoms that you describe are characteristic of a
fluorescent light housing that is not properly grounded. You may want
to check the grounding on these fixtures.

Harry C.

 

[Jerry Greenberg]

By coincedence, the new ballast transformers were defective, or there
was some type of electrical problem. A knowledgable electrician should
have been able to work this out for you.

Jerry Greenberg
http://www.zoom-one.com

--


Michael <NoSpam@this.addy> wrote in message news:<3F1C3304.15C50AD5@this.addy>...

Two fluorescent fixtures in two bathrooms of my mother's house seem to
be possessed. Both are
integral parts of medicine cabinets and are 20 years old, as is the
house. Eight or nine
years ago one light started acting up: when the wall switch was flipped
ON, sometimes the tube would come on only dimly while other times it
would come on fully. When ON dimly, the tube could be made to come on
fully by touching a finger to the metal cabinet. New tubes exhibited
the same symptom and behavior. Two years ago I replaced the ballast and
that seemed to fix the problem; it didn't fail to fully fire in several
dozen ON/OFFs. But last winter that same fixture started acting up in
the same old way, and last week a second, identical fixture in another
bathroom followed suit. Mom is on the war path, demands satisfaction.
But I don't know what else I can do. Ripping out the two medicine
cabinets and installing ones that have incandescent lights is definitely
a non-starter.

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground? I'm in NY and fixtures are in NH, so
I can't check what the actual case is.

Finally, is there a more appropriate NG for this query?

Tnx,
Michael

 

[Michael]

Tom Biasi wrote:

Hi Michael,
Since its the bathroom I would bet on the corroded contacts.
Sometimes even the slightest coupling to ground or AC Hum will cause a
borderline lite to come on.
Next time you see one flickering run your finger up and down the tube and
see what happens.
regards,
Tom

Yup ... I forgot to add that touching the glass tube also causes the
tube to come on fully.

I used to have old circular fluorescent on the ceiling in my own kitchen
and in cold weather it would do the come-on-dim thing. Reaching up with
a metal broom handle and touching the glass tube made it fire. I
finally ripped the thing out.

 

[Michael]

Charles Schuler wrote:

I can't answer all your questions but can suggest that corrosion of the
contacts is a possibility. Also, I have found that the contacts lose their
tension. Touching the cabinet? That's strange ... I'll be curious to see
if you get any replies about that!

Possible, I guess, but I did try to make good connections by
continuously rotating the tube for about half a minute. Did that just
to make sure ..... in desperation, because I never did like or trust the
contacts in fluorescent tube sockets.

 

[Michael]

Harry Conover wrote:

Michael, the symptoms that you describe are characteristic of a
fluorescent light housing that is not properly grounded. You may want
to check the grounding on these fixtures.

Harry C.

I'll definitely check ground connections next time I visit home. Since
touching the metal cabinet around the light has an effect, it seems
likely that the cabinet does *not* have a solid ground. I don't
understand though why two lights - one upstairs and one downstairs -
worked fine for about 10 years.

 

[Don Klipstein]

In article <3F1C3304.15C50AD5@this.addy>, Michael wrote:

SNIP

What are common causes of "fizzling" fluorescents? Are "hot" and
"return" swapped? Should the metal cabinet be solidly
grounded?...insulated from ground?

1. Are the ballasts 2-bulb ballasts? Especially "trigger start" ones?

If one bulb glows dimly and the other one does not glow at all and you
tried new bulbs:

a) The fixture needs to be grounded. Failure to start due to lack of
grounding is often inconsistent and may vary seasonally. If touching a
bulb or the fixture helps, then chances are the problem is lack of proper
grounding.

b) A hot-neutral reverse may cause this.

c) Check the voltage across the two contacts in each socket - it should
be around 9 volts.

d) Try twisting the bulbs around for better contact. If this fixes it,
then you will have to clean the contacts in the sckets with fine
sandpaper or get new sockets (lampholders). It may be easier to cut new
lampholders from a ballast that has them or from the cheapest new fixture
you can find than to find a supplier that sells just a few of them.

e) Make sure you have the proper wattage bulb for the ballast. Nowadays
2-foot (and worse still 4-foot) fluorescent bulbs come in different
wattages.

Same story if both bulbs are out.

If all bulbs glow dimly then the problem is almost certainly not
improper grounding or hot-neutral reverse.

2. Bulb glows dimly with a single bulb trigger start ballast: By far the
most likely explanation is poor contact with one pin, or maybe with one
pin on each end of the bulb, or broken connection that results in lack of
that roughly 9 volts across the pins on each end.

3. Both bulbs glow a little dim but not very dim, and/or flicker rapidly
in unison, or alternate between normal brightness and dim or dim/flickery
in unison, and the bulbs are known good:
Some 2-bulb trigger start ballasts, especially for 20 watt bulbs, are
marginal in design. Try a different brand of bulb. Be sure you have the
proper wattage bulb.

4. If the fixture has starters:

Voltage measurements across the two contacts of each socket will be
meaningless and ideally read zero but could be anything depending on the
impedance of your voltmeter.

Try replacing the starters, although bad starters usually cause symptoms
other than the ones you described.
Bad starters can cause rapid degradation of good bulbs and bad bulbs can
cause bad extra wear on good starters.

5. Try reading:

http://www.misty.com/~don/f-lamp.html (Sam Goldwasser's F-lamp FAQ)
http://www.misty.com/~don/ltrouble.html (my troubleshooting guide)

- Don Klipstein (don@misty.com)

 

[Don Klipstein]

In article <3F1D4C04.B18F06AF@this.addy>, Michael wrote:

Harry Conover wrote:
Michael, the symptoms that you describe are characteristic of a
fluorescent light housing that is not properly grounded. You may want
to check the grounding on these fixtures.

I'll definitely check ground connections next time I visit home. Since
touching the metal cabinet around the light has an effect, it seems
likely that the cabinet does *not* have a solid ground. I don't
understand though why two lights - one upstairs and one downstairs -
worked fine for about 10 years.

In strange static-assisted cases, try cleaning the bulbs. In a few
areas especialy coastal areas, a very fine salty film on the bulbs may, at
times of higher humidity, mess up the electric field distribution within a
bulb that is trying to start.
This is almost certainly not the explanation if all bulbs are glowing
dimly rather than any bulbs not glowing at all.

- Don Klipstein (don@misty.com)

 

[Michael]

Don Klipstein wrote:

1. Are the ballasts 2-bulb ballasts? Especially "trigger start" ones?

If one bulb glows dimly and the other one does not glow at all and you
tried new bulbs:

a) The fixture needs to be grounded. Failure to start due to lack of
grounding is often inconsistent and may vary seasonally. If touching a
bulb or the fixture helps, then chances are the problem is lack of proper
grounding.

b) A hot-neutral reverse may cause this.

c) Check the voltage across the two contacts in each socket - it should
be around 9 volts.

d) Try twisting the bulbs around for better contact. If this fixes it,
then you will have to clean the contacts in the sckets with fine
sandpaper or get new sockets (lampholders). It may be easier to cut new
lampholders from a ballast that has them or from the cheapest new fixture
you can find than to find a supplier that sells just a few of them.

e) Make sure you have the proper wattage bulb for the ballast. Nowadays
2-foot (and worse still 4-foot) fluorescent bulbs come in different
wattages.

Same story if both bulbs are out.

If all bulbs glow dimly then the problem is almost certainly not
improper grounding or hot-neutral reverse.

2. Bulb glows dimly with a single bulb trigger start ballast: By far the
most likely explanation is poor contact with one pin, or maybe with one
pin on each end of the bulb, or broken connection that results in lack of
that roughly 9 volts across the pins on each end.

3. Both bulbs glow a little dim but not very dim, and/or flicker rapidly
in unison, or alternate between normal brightness and dim or dim/flickery
in unison, and the bulbs are known good:
Some 2-bulb trigger start ballasts, especially for 20 watt bulbs, are
marginal in design. Try a different brand of bulb. Be sure you have the
proper wattage bulb.

4. If the fixture has starters:

Voltage measurements across the two contacts of each socket will be
meaningless and ideally read zero but could be anything depending on the
impedance of your voltmeter.

Try replacing the starters, although bad starters usually cause symptoms
other than the ones you described.
Bad starters can cause rapid degradation of good bulbs and bad bulbs can
cause bad extra wear on good starters.

5. Try reading:

http://www.misty.com/~don/f-lamp.html (Sam Goldwasser's F-lamp FAQ)
http://www.misty.com/~don/ltrouble.html (my troubleshooting guide)

- Don Klipstein (don@misty.com)

So much good stuff. Enough to keep me reading for quite a while. I
have a good feeling that what I need to know is in there somewhere.
Many thanks, Don.

 

[Dan Fraser]

Many florescent fixtures need to be grounded to fire properly. Two wire
fixtures need the correct wire connected to the neutral and hot. If they
are reversed, they will be hard to start. That you can touch yours and
have them start indicates you may indeed have a reversed hot and
neutral.

--
Dan Fraser

From Costa Mesa in sunny California
949-631-7535 Cell 714-420-7535

Check out my electronic schematics site at:
http://www.schematicsforfree.com
If you are into cars check out www.roadsters.com