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small burn mark on a 10k lamp


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#1 Patrick Nuse

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Posted 31 January 2007 - 02:58 AM

I recently purchased a Mole 10K. It came with a used lamp that looks almost new. however it has a small 2mm by 1mm black mark. Looks like something got baked on the glass. can someone tell me if this is going to be a problem? is that enough to cause the lamp to break when it gets hot?
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#2 timHealy

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Posted 31 January 2007 - 05:19 AM

I recently purchased a Mole 10K. It came with a used lamp that looks almost new. however it has a small 2mm by 1mm black mark. Looks like something got baked on the glass. can someone tell me if this is going to be a problem? is that enough to cause the lamp to break when it gets hot?



There really isn't enough of a description to be sure but I would say probably not. There are many kinds of defects that may look like they may be a problem without actually being one. With tungsten bulbs, the only clear thing I would look out for besides the obvious physical damge or a burned out filament is a yellow discoloration inside the bulb that is opaque and one cannot see the filament through it. Some refer to it as a "gasser". I am not sure what is technically happenned to this type of bulb, but I would say it has a problem with the vacuum that the filament is in and the bulb is in imminent danger to go. So it needs to be replaced right away. Perhasp the Harry Box book has a description of what casues this.

Can yu post a photo of your bulb?

Best

Tim
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#3 Patrick Nuse

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Posted 01 February 2007 - 05:12 AM

There really isn't enough of a description to be sure but I would say probably not. There are many kinds of defects that may look like they may be a problem without actually being one. With tungsten bulbs, the only clear thing I would look out for besides the obvious physical damge or a burned out filament is a yellow discoloration inside the bulb that is opaque and one cannot see the filament through it. Some refer to it as a "gasser". I am not sure what is technically happenned to this type of bulb, but I would say it has a problem with the vacuum that the filament is in and the bulb is in imminent danger to go. So it needs to be replaced right away. Perhasp the Harry Box book has a description of what casues this.

Can yu post a photo of your bulb?

Best

Tim

It's on the very surface of the glass, even with it. not pitted.

There really isn't enough of a description to be sure but I would say probably not. There are many kinds of defects that may look like they may be a problem without actually being one. With tungsten bulbs, the only clear thing I would look out for besides the obvious physical damge or a burned out filament is a yellow discoloration inside the bulb that is opaque and one cannot see the filament through it. Some refer to it as a "gasser". I am not sure what is technically happenned to this type of bulb, but I would say it has a problem with the vacuum that the filament is in and the bulb is in imminent danger to go. So it needs to be replaced right away. Perhasp the Harry Box book has a description of what casues this.

Can yu post a photo of your bulb?

Best

Tim

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#4 Rob van Gelder

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Posted 12 February 2007 - 03:42 AM

A Gasser means that there is a air leak in the glass, most likely along the wires that go through it.
Often there is a special foil (molybdinium) that connects the metal wires with the internal wires and it can leak there through cracks.

This can cause the bulb to blacken (tungsten deposits on the glass) or indeed the yellow haze, another element condensing on the glass, in both cases, the lamp life is limited or finished.

The spot you are looking at could be some metal or dirt piece, caught in the glass, It might affect the lamp life as this is a point of stress in the glass and 10Kw lamps will get very hot.

I would check it regularly, when operating the lamp and check if it becomes bigger or deeper.
You don't want your lamp to explode an possibly ruin the reflector and/or fresnel
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#5 Patrick Nuse

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Posted 16 February 2007 - 02:19 AM

A Gasser means that there is a air leak in the glass, most likely along the wires that go through it.
Often there is a special foil (molybdinium) that connects the metal wires with the internal wires and it can leak there through cracks.

This can cause the bulb to blacken (tungsten deposits on the glass) or indeed the yellow haze, another element condensing on the glass, in both cases, the lamp life is limited or finished.

The spot you are looking at could be some metal or dirt piece, caught in the glass, It might affect the lamp life as this is a point of stress in the glass and 10Kw lamps will get very hot.

I would check it regularly, when operating the lamp and check if it becomes bigger or deeper.
You don't want your lamp to explode an possibly ruin the reflector and/or fresnel

Thanks for the info!

with that I think I'm going to just play it safe and replace it.
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Visual Products

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FJS International, LLC

Tai Audio

CineTape

Broadcast Solutions Inc

Metropolis Post

Ritter Battery

Abel Cine

Technodolly

Gamma Ray Digital Inc

Opal

The Slider

Wooden Camera

Media Blackout - Custom Cables and AKS

Willys Widgets