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Archive 2013 · What is this in a flash tube?
  
 
Jayem1
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p.1 #1 · What is this in a flash tube?


Hope some knowledgeable members in the Lighting forum can help me with this issue -

I just picked up a pair of second hand Elinchrom strobes on B&S board. Upon inspection after receiving them, I spotted a patch of deposit about a half-inch size inside the flash tube of one strobe (see photos below).







closer look:






Has anyone seen anything like this in a flash tube? How could something like this develop? I am not sure how serious this is and I could not find any information online to alliviate my concern. This stuff certainly does not belong there. The strobe itself seems to fire fine. I have not used it to shoot anything, just a couple of test pops. Hopefully someone on this board could provide some insight.

Thanks!



Feb 26, 2013 at 11:54 PM
BrianO
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p.1 #2 · What is this in a flash tube?


If I had to guess, I'd say the chemical used to coat the inside of the tube was vaporized, and then condensed and crystalized on itself. I know titanium dioxide is sometimes used in xenon tubes, so maybe those are titanium dioxide nanotubes.

No idea how that would happen, but it's all I can think of.



Feb 27, 2013 at 04:45 AM
cgardner
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p.1 #3 · What is this in a flash tube?


My guess would be Pixie Dust since it's widely acknowledged Elinchrom gear has magical qualities.

The only thing in the tube besides xenon (and the coating Brian mentioned) are the electrodes at the ends which over time are vaporized and coat the tube, especially at the ends. My guess is that's what it is, vaporized electrode material deposited near where the trigger wire current originates.

The tube is an open switch - air (xenon) gap. It is fired by first sending a small "trigger" charge into the wire around the tube which ionizes the gas to the point it becomes conductive. That completes the circuit to the main capacitors between the electrodes at the ends and WHAM the xenon reaches a plasma state and emits a big flash of light.

Older designs stayed lit until the capacitors ran out of charge. Modern designs use a "clamp" circuit similar to speedlight to cut off the power (preserving it in the capacitors for the next shot) or shunt it to "dump" resistors. Both strategies more precisely control the flash duration via controlling the time between the trigger circuit firing and the "off switch" clamp kicking in.

I'd guess that tube is near the end of it's useful life so you might want to order a spare if user replaceable or start saving for the repair bill.




Feb 27, 2013 at 12:00 PM
Jayem1
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p.1 #4 · What is this in a flash tube?


Thanks for the info. That's what I am afraid to hear.

The new flash tube is not cheap, easily cost half of what I paid for the strobe.




Feb 27, 2013 at 06:01 PM





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