Failure resulting in hole punched in GE CFL

[Sam Goldwasser]

This one was rather strange, at least to me.

One of two horizontally mounted spiral GE CFLs in a semi-enclosed fixture
simply winked out. It's one I had repaired cracked solder joints on a year
or so ago so I figured time to resolder if the transistors/MOSFETs weren't
toast.

Checked all common suspects for shorts/opens as well as the lamp for
good filaments, no problesm found.

Resoldered some questionable joints - no sign of life.

Then I noticed IT - a dimple near one end of the tube and a resistor
lead could be inserted straight into the inside. A pinpoint on the
inside surface of the glass must have gotten really hot.

How often do you see that?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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[Sam Goldwasser]

Not often, but then I usually just replace bad bulbs.

What fun is that?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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[N_Cook]

This one was rather strange, at least to me.

One of two horizontally mounted spiral GE CFLs in a semi-enclosed fixture
simply winked out. It's one I had repaired cracked solder joints on a year
or so ago so I figured time to resolder if the transistors/MOSFETs weren't
toast.

Checked all common suspects for shorts/opens as well as the lamp for
good filaments, no problesm found.

Resoldered some questionable joints - no sign of life.

Then I noticed IT - a dimple near one end of the tube and a resistor
lead could be inserted straight into the inside. A pinpoint on the
inside surface of the glass must have gotten really hot.

How often do you see that?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Is the keyphrase "horizontally mounted " and the hole was where the mercury
condensed into a ball ?

 

[Franc Zabkar]

Is the keyphrase "horizontally mounted " and the hole was where the mercury
condensed into a ball ?

If this was a real problem, then wouldn't you expect to see these
kinds of failures in the long, straight, horizontally mounted
fluorescent tubes?

- Franc Zabkar

 

[Franc Zabkar]

This one was rather strange, at least to me.

One of two horizontally mounted spiral GE CFLs in a semi-enclosed fixture
simply winked out. It's one I had repaired cracked solder joints on a year
or so ago so I figured time to resolder if the transistors/MOSFETs weren't
toast.

Checked all common suspects for shorts/opens as well as the lamp for
good filaments, no problesm found.

Resoldered some questionable joints - no sign of life.

Then I noticed IT - a dimple near one end of the tube and a resistor
lead could be inserted straight into the inside. A pinpoint on the
inside surface of the glass must have gotten really hot.

How often do you see that?

A colleague claims that he witnessed a case where the neck of Philips
CRT was pinholed when his colleague removed the tuning capacitor in
the line stage. <shrug>

BTW, I've had a bad run with Edapt CFLs. Typical faults include dry
joints, O/C startup resistors, and O/C filaments. Strangely, in the
latter case the lamp flashes once when I touch it.

- Franc Zabkar

 

[Sam Goldwasser]

Is the keyphrase "horizontally mounted " and the hole was where the mercury
condensed into a ball ?

I don't know. There's supposed to be very little mercury in these things
though.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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[Sam Goldwasser]

Never. What could get hot enough to do that?

That's really the question. Unless as someone else suggested, that's
where a bit of mercury condensed and somehow the discharge went to that
instead of the filament. I have no idea if that's even possible.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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Important: Anything sent to the email address in the message header above is
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[Sam Goldwasser]

If this was a real problem, then wouldn't you expect to see these
kinds of failures in the long, straight, horizontally mounted
fluorescent tubes?

Don't know if it's a real problem, but it was a real failure.

The current density is lower in the fat straight ones but since I have
no idea how this happened, it's hard to even speculate on whether other
types are prone to it.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Franc Zabkar]

Don't know if it's a real problem, but it was a real failure.

The current density is lower in the fat straight ones but since I have
no idea how this happened, it's hard to even speculate on whether other
types are prone to it.

I'd return the faulty CFL to GE with a comment to the effect that a
lamp that leaks mercury into the household atmosphere is a potentially
serious health hazard. Ask them how long it will be before you will be
able to tell whether the toxins have poisoned your liver. I guarantee
you'll get a box full of free replacements in a matter of days.

- Franc Zabkar

 

[hr(bob) [email protected]]

I'd return the faulty CFL to GE with a comment to the effect that a
lamp that leaks mercury into the household atmosphere is a potentially
serious health hazard. Ask them how long it will be before you will be
able to tell whether the toxins have poisoned your liver. I guarantee
you'll get a box full of free replacements in a matter of days.

- Franc Zabkar

Please let us know what GE says when you contact them!!!!