This is topic Vertical Lamphouses in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Brett Rankin (Member # 31) on 12-07-1999, 11:58 PM:
I tried this thread on Historyinacan a while back, and I thought I'd give the rest of you a shot at it.I have a Cinemecannica 500w xenon vertical lamphouse with an XBO type bulb. The reflector is good, and I've focused the bulb as much as I can. The problem is that the center vertical third of the screen is darker than the rest (quite noticeably) and seems to vibrate and move.
What's going on? The bulb only has about 20 hours on it. Do verticl lamphouses just do that? Are there any advantages/disadvantages to vertical compared to horizontal? Efficiency? Brightness?
All help is appreciated- thanks.
Brett
Posted by Ken Layton (Member # 133) on 12-08-1999, 12:45 AM:
What is the model number of your lamphouse?
If it's the Xetron/Cinemeccanica CX-450, then the manual for the CX-900 is the same.
You should download it from the Adobe manual download section here at film-tech.The Xetron/Cinemeccanica CX-450 and CX-900 use a field flattener diffuser lens mounted inside the nose cone. This diffuser provides a flat, uniform field of light when this lamphouse is used with 35mm projectors. This lamphose was also used with 16mm projectors too. THE DIFFUSER IS NOT USED WHEN OPERATED WITH 16mm PROJECTORS. It's possible that the diffuser lens is missing on your lamphouse (meaning that it was used previously on a 16mm machine).
The diffuser lens also MUST be mounted a certain way as described in the manual. It is directional---much the same as Poloroid lenses.
Posted by Brett Rankin (Member # 31) on 12-08-1999, 07:04 PM:
The model number is: CX-034I see what appearsto be a diffuser lens, but there is no nose cone. Just a shortmetal cylindar that's just hanging there. What makes it darker in the middle than the rest, and what is shaking?
Posted by Ken Layton (Member # 133) on 12-12-1999, 01:06 PM:
Some makes of vertical lamphouses had a small "auxillary mirror" near the bulb to remove the bulb's shadow. Adjustment of it was critical to obtaining smooth, even light output.
Posted by Gordon McLeod (Member # 33) on 12-12-1999, 03:28 PM:
The verticle of that size would 450watt not 500 watt. The CX450/900's did not have an auxilary mirror but a diffusor in the nose cone. The working distance and optical alignment are very criticle to any verticle system lineing up correctly.
As for the shaking is it possible you mean flickering and that could be two things the lamp being old and ready to fail
2 the rectifier either a bad diode(s) or one phase missing (3phase)unit