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Author Topic: XENON 7K lamp alignment problems Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 08-09-2013 05:18 PM                     During my last two lamp changes, I have noticed a "hot Spot" located in the lower center of the screen when running the test loop(and viewing our feature film). No amount adjustment to the x, y or z axis can move this hot spot to the center of the screen. I have spoken with our IMAX tech and he says I basically have to live with this current scenario. Does anyone have any suggestions as to why this is happening?  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 08-10-2013 06:00 AM                     sounds like your IMAX "tech" is lazy  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 08-10-2013 09:43 AM                     What kind of projector though? Is this the Niagara Falls theatre? I think NF has the Imax "Classic" with a 7kW aircooled lamphouse, as I recall that type has no folding mirror (been a while, I could be mistaken). Either the reflector is distorted or the reflector optical axis is not coaxial with the lens optical axis. Neither was unusual with the 7kW lamphouse. I think the reflector had to be cut to fit and the cutting could distort the shape, but it can be checked with a point source light (like a krypton 2AA mini maglight with the front cap off, poked through the reflector hole from the back) - the light pattern projected from the mirror onto a wall contains a bunch of concentric circles which will be round from a good reflector, odd shaped if the shape is distorted. Alignment of the axes was done with either a string (old school, not very accurate) or with a laser mounted in the reflector hole with its beam on the reflector axis, the mirror is moved so the beam is down the centre of the lens axis (the reflected light pattern from the lens elements then becomes concentric circles, one for each element).  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 08-10-2013 04:34 PM                     I'm hoping it gets resolved at my next service this month. It's been a challenge finding a midway point between reducing the "hot spot's" brightness by pulling back on the "Z" axis vs keeping the overall image as bright as possible by increasing the rectifier's power.We currently try to hover around 155 amps and 32 DC volts in order to attain longevity with our lamp (700 + hours). The last few weeks of the lamp life, the amps usually drop to around 150. I'm the "new kid on the block" here so I'm trying to get as much knowledge as possible. Thanks everyone for your input on this matter.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-17-2013 03:03 PM                     Pyramid Place Imax remember it well It had a classic aircooled machine the reflector came from ORC if memory serves  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 08-17-2013 07:43 PM                     Can't wait for our next service call. Laser alignment is in the works!  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 08-26-2013 09:15 PM                     Turns out the mirrors were out of alignment. Balance has been restored thanks to our service tech.  |  IP: Logged

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