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Let There Be Light, There Was Light.......


Isaac Hunt
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Lucas, Prince Of Darkness had other ideas

Checking a car for the MOT and we had a 380 stop lamp out.

new bulb fitted, all good.

checked the new bulb on the morning of MOT, blown again WTF

put another bulb in, all good.  Run it down the test centre

Tester puts it on the ramp and I immediately notice the bloody bulb has blown AGAIN FFS

2E4C6CB3-41E9-4F0C-9126-AC3CED0B07DD.thumb.jpeg.26f5584e21bdaa1e3c26b4f9c426f3f7.jpeg

No 2 & 3 were from my garage shelf stock, had them a good while, didn’t realise that they had a ‘best before date’ or ‘use by date’.  

 

 

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12 hours ago, Isaac Hunt said:

Lucas, Prince Of Darkness had other ideas

Checking a car for the MOT and we had a 380 stop lamp out.

new bulb fitted, all good.

checked the new bulb on the morning of MOT, blown again WTF

put another bulb in, all good.  Run it down the test centre

Tester puts it on the ramp and I immediately notice the bloody bulb has blown AGAIN FFS

2E4C6CB3-41E9-4F0C-9126-AC3CED0B07DD.thumb.jpeg.26f5584e21bdaa1e3c26b4f9c426f3f7.jpeg

No 2 & 3 were from my garage shelf stock, had them a good while, didn’t realise that they had a ‘best before date’ or ‘use by date’.  

 

 

gas inside lost its edge.......

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4 hours ago, Isaac Hunt said:

Lucas, Prince Of Darkness had other ideas

Checking a car for the MOT and we had a 380 stop lamp out.

new bulb fitted, all good.

checked the new bulb on the morning of MOT, blown again WTF

put another bulb in, all good.  Run it down the test centre

Tester puts it on the ramp and I immediately notice the bloody bulb has blown AGAIN FFS

2E4C6CB3-41E9-4F0C-9126-AC3CED0B07DD.thumb.jpeg.26f5584e21bdaa1e3c26b4f9c426f3f7.jpeg

No 2 & 3 were from my garage shelf stock, had them a good while, didn’t realise that they had a ‘best before date’ or ‘use by date’.  

the milky white deposits indicates a fast/complete air leak like a crack/broken bulb, a completely failed glass to metal seal or something such

(a hot tungsten filament will react with air to form tungsten trioxide)

and the dark blue/black despots on the one on the far right indicate a slow air leak like a leaky glass to metal seal for the lead in wires

(when there is a very slow leak Tungsten pentoxide is formed instead which has a smokey dark blue colour)

so simply a bad run in with either damaged or defective bulbs, when stored properly lightbulbs dont have any sort of realistic shelf life, the oldest Lightbulb in my collection, from 1893 works just fine :)

 

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9 hours ago, LightBulbFun said:

the milky white deposits indicates a fast/complete air leak like a crack/broken bulb, a completely failed glass to metal seal or something such

(a hot tungsten filament will react with air to form tungsten trioxide)

and the dark blue/black despots on the one on the far right indicate a slow air leak like a leaky glass to metal seal for the lead in wires

(when there is a very slow leak Tungsten pentoxide is formed instead which has a smokey dark blue colour)

so simply a bad run in with either damaged or defective bulbs, when stored properly lightbulbs dont have any sort of realistic shelf life, the oldest Lightbulb in my collection, from 1893 works just fine :)

 

illuminating answer from as's master of lumens

here is a question, recently had to replace a hid on the ovlov, new bulb is a lot brighter than the old one, both are same wattage, do hid's lose brightness with age or becausee its a new bulb it is just brighter

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7 minutes ago, big_al_granvia said:

illuminating answer from as's master of lumens

here is a question, recently had to replace a hid on the ovlov, new bulb is a lot brighter than the old one, both are same wattage, do hid's lose brightness with age or becausee its a new bulb it is just brighter

Yes they do deteriorate over time, I have always changed both when having cars with HID's as its sods law the other will fail immediately after.

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2 hours ago, big_al_granvia said:

illuminating answer from as's master of lumens

here is a question, recently had to replace a hid on the ovlov, new bulb is a lot brighter than the old one, both are same wattage, do hid's lose brightness with age or becausee its a new bulb it is just brighter

HID Lamps (and pretty much all other light sources) do suffer from lumen deprecation over their useful life time

in fact some discharge lamps have their lifetime determined not by when they stop working but by how much light they put out by the end of that lifetime rating 

for example a High Pressure mercury lamp of good quality can easily burn for 40 years in a streetlight, the only snag is just by the end of those 40 years it will be rather dim and green, however consuming the full power rating of the lamp

because as the tungsten electrodes evaporate they coat the inside of the arc tube with their sputtered material blocking light from the arc tube escaping and causing the lamp to go dim and dimmer over time

so they are often rated to say 24,000 hours to a percentage of their original lumen output, after which the lamp efficiency drops too much and it should be replaced with a new lamp

 

and this is whats happened in your HID head lamp, as well other reactions with the components of the lamp thanks to the additional halides and high load everything is under in a metal halide lamp (which a car HID head lamp is)

if you look at the well used lamp and compare it to a new one, you may see the arc tube (the little ball shaped thing in the middle of the lamp) of the well used lamp has gone a white or black opaque colour compared to the new lamp

and this will of course not only block light but also degrade optical performance, leading to it being a fair bit dimmer then a new lamp! :) 

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