Fuse Resistors, CFLs, and God Awful SMPSes

In summary, the other day I came into my living room, and noticed that the CFL in one of my lamps was flickering like crazy. Of course having a propensity to possibly fatal curiosity as some humans do, I walk over and grab the base to see if maybe the bulb isn't seated properly. The base of the bulb is scorching hot! A second later, the bulb starts smoking. I quickly pull the plug and disaster is averted. After calming down for a minute and nursing my burnt thumb, I decide to pop the bulb open to see what could have happened. The inside of the bulb is melted and charred, but on the ground lead of the wires leading to the switching power supply is what looks
  • #1
bitrex
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The other day I came into my living room, and noticed that the CFL in one of my lamps was flickering like crazy. Of course having a propensity to possibly fatal curiosity as some humans do, I walk over and grab the base to see if maybe the bulb isn't seated properly. The base of the bulb is scorching hot! A second later, the bulb starts smoking. I quickly pull the plug and disaster is averted. After calming down for a minute and nursing my burnt thumb, I decide to pop the bulb open to see what could have happened. The inside of the bulb is melted and charred, but on the ground lead of the wires leading to the switching power supply is what looks like the melted remnants of a wire-wound resistor, still stubbornly holding itself together across the line. Probably a transistor in the supply gave up the ghost and caused a short, but I wondered to myself just how long this "resistor-fuse" would have drawn short circuit current? Until it caught fire, I'm guessing. I'm not even sure the manufacturer used a proper resistor fuse, it could have just been an ordinary resistor for all I know!

A few days later, I had an ATX power supply fail - it couldn't provide any current on the 5 volt standby line. Thinking it might be an easy fix I opened up the power supply, and the soldering job is the biggest mess I've ever seen. On the underside of the board it looks like some of the main ground buses were too resistive or something, because the manufacturer has taken big pieces of bare jumper wire and slapped them on top of the ground buses and tacked them in place with big blobs of solder. :eek: Half the joints on the board look cold, though this could just be a side effect of it being "RoHS" compliant the job really looks awful. And of course a big ol' resistor on the primary side where on other supplies there is a proper fuse. And this is in a supply from a supposedly high quality "boutique" manufacturer that cost nearly $100.

The lesson learned is that I don't leave my house with SMPSes running anymore. :frown:
 
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  • #2
Yikes, the CFL (compact flourescent lamp) ballast story is downright scary. Who was the manufacturer of the light fixture with the ballast? Who made the ballast, can you tell?
 
  • #3
I will try to get some photos up when I get home after the weekend.
 
  • #4
This really worries me.
The public is being advised to check any spiral type lightbulbs in your home as they may potentially pose a fire hazard. Specifically, these bulbs are identified as GLOBE MINI - SPIRAL 13W self ballested lamps produced between January 2002 and April 2003. These compact spiral fluorescent 13 watt bulbs are being sold throughout Canada and the USA.
http://www.city.quintewest.on.ca/services/fire/prevention.htm"
Here's a picture of what could happen:
BurntBulb3.jpg
 
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  • #5
I have had a similar thing with a new CFL. It had started smoking on me and then the base plastic started melting and turning black like it was on fire. I immediately switched the circuit off - makes me wonder about the quality of these things. Maybe I'll keep using incandescents - saves me money from running the gas furnace :)
 
  • #6
maybe what we need here are some space-age flame-resistant ceramic bases.
 

FAQ: Fuse Resistors, CFLs, and God Awful SMPSes

1. What are fuse resistors and why are they important in electronics?

Fuse resistors are a type of resistor that is designed to act as a fuse in the event of a circuit overload. They have a low melting point and will break the circuit when too much current flows through, protecting other components from damage. They are important in electronics because they help prevent fires and other safety hazards.

2. What is a CFL and how does it work?

A CFL, or compact fluorescent lamp, is a type of energy-saving light bulb that uses a fluorescent tube to produce light. It works by sending an electric current through a tube filled with gas, which causes the gas to emit ultraviolet light. This light then interacts with a phosphor coating on the inside of the tube, producing visible light.

3. Why are SMPSes considered "God awful"?

SMPSes, or switched-mode power supplies, are often considered "God awful" because they can be difficult to troubleshoot and repair. They use complex circuitry and can be sensitive to variations in input voltage, making them prone to failure. Additionally, they can produce electromagnetic interference that can disrupt other electronic devices.

4. Can SMPSes be replaced with traditional linear power supplies?

Yes, SMPSes can be replaced with traditional linear power supplies, but there are some trade-offs. Linear power supplies are simpler and more reliable, but they are also larger and less energy-efficient. SMPSes are smaller and more efficient, but they can be more difficult to repair.

5. Is there a connection between God and electronics?

No, there is no direct connection between God and electronics. However, some people may view the complexity and power of electronics as evidence of a higher power, while others may see it as a result of human innovation and scientific understanding.

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