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Hello,

Can anyone shed some light (pardon the pun) on what could be causing a Osram 2k xenon lamp in a knisley L1 lamphouse to suddenly start a BAD case of the shudders, arc burning way out of position at times, again last night after running the 1st show no problems, 30 mins into the 2nd show, was burning so badly I had to refocus reflector just to keep light on the screen!

Today it was back to normal, and I had to adjust reflector back to normal?

NOT a power problem, that I know of, had done this several weeks ago too, only has around 1000 hrs on it, electrodes look great!?!?!?!?

We had one along time ago that ended up being a leaker, and after it lost some of it's gas was a mess like this, but this damn thing fixes itself! and damn sure leaking gas isn't going back in!

Thanks!

Filter capacitor or a diode in the power supply could be going bad. If the power supply is a 3 phase type it's possible that one of the phases is going goofy. Check all connections inside power supply and lamphouse for cleanliness & tightness.

Is bulb cooling fan up to snuff? Any vents clogged. Fins on blower wheel clean? How about rooftop lamphouse exhaust fan?

Also possible bulb is going bad.

I guess it's possible 1 leg of the 3phase could be going nuts, kinda hard to monitor though... will clean up the connections on the p/s, lamphouse is spotless, fan is working, just happens random, several weeks ago it went nuts from the 1st moment the arc was lit, settled down maybe an hour later, yesterday it was plenty warm after the 1st show... weird...

Filter cap COULD be but hard to tell w/o a scope on the dc line...

I have no problem with any of those things being the problem, bulb too, but generally things don't "fix" themselves once broken?!?!?!?

Thanks for the help!

Check for an open diode usually this is what causes the flicker. most likely the cuplprit was a loose conncetion to the diode and it cause it to get hot and open. if the lamp has a hard time striking or won't stay lit it can be an open diode. the bad diode usually welds its self to the rectifier. also check your relay to the 3 phase connection to see if you have a burnt leg.

I agree it sound like there's excess current ripple in the output of the rectifier. Losing a leg of 3-phase, or an intermittent bad diode or contactor would do it, and could have temporarily "fixed itself".

Murphy's Law says it will happen again this Friday evening at 8:37 pm.

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oh no,

That guy Murphy again! (damn smart man!)

yeah, your rite, I guess at high currents components could "weld themselves" and work again for a short while... Will have a good going over everything and see what I can find.

Thanks!

Contactor is what I meant not relay I could not think of the word.

It would be helpfull to know what make of lamp and rectifier
If you have one of the newer switchers then that is a completely different kettle of fish
I have also noticed that some of the Kniesly magnets are not that good and can cause intermitent instabality with certain lamps
Also check to make sure the exhaust is constant if there is sudden changes in draft the lamp will be come unstable

It is an Osram lamp,2K

Lamphouse is like 6 years old as is the p/s, I will get the model info off it tonight.

No problem with exhaust, everything is kept clean in the booth, however the p/s in IN THE BASEMENT???

Moron's put it down there, I dunno...

but never been a problem before...

Thanks!

Check the cable between the booth and basement and its connectors they may have corroded

Nothing looks bad, all connections seemed clean and snug, I am going to change the magnet in a few days when someone drops one off, will let ya all know how it goes!

Tony.

Be carefull installing it it must be in the correct polarity and position