Film-Tech Forum ARCHIVE: Xenon Flicker

This is topic Xenon Flicker in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Steve McAndrew (Member # 8865) on 06-02-2016, 06:10 AM:

Hi

What generally causes the arc in a Xenon lamp to 'jump' about and flicker?

Is this the sign of an old lamp?

Thanks

Posted by Sam D. Chavez (Member # 1841) on 06-02-2016, 09:29 AM:

We would need to know brand of bulb first. Then brand of lamp house, power supply, sufficient exhaust. The list goes on and on. Did this just start happening or was it always a problem?

That will get this topic going. We are talking Film right?

Posted by Dave Macaulay (Member # 813) on 06-02-2016, 10:59 AM:

It means the arc is unstable, jumping around rather than sitting happily in mostly one line between the cathode and anode.
Just being old can create weird erosion and "horns" on the anode and pointy little crystalish stuff on the cathode tip. The arc jumps randomly around these things.
High ripple on the power supply will cause accelerated development of the anode horns especially.
Low or over cooling can cause instability.
Many lamphouses have arc stabilizing magnets, some are installed backwards. If yours has a magnet confirm it's the right way around.

Posted by Steve McAndrew (Member # 8865) on 06-02-2016, 11:53 AM:

Thanks for the replies.

The lamp is in a 16mm EIKI-EX2000n Projector. The lamp brand is Ushio, it's 350w.

For info the lamp strikes first time every time and generally looks in good condition.