This is topic Christie SLC exhaust question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Manuel Francisco Valencia (Member # 710) on 06-17-2002, 05:57 PM:
My problem or question is regarding the exhaust sensor. For all of you who are not familiar with this console let me explain how it works. On the inside of the console at the top there is a little metal "leaf" that is at the very base of the exhaust tubing. When the exhaust is running the moving air lifts up the leaf and in turn allows the bulb to ignite. If there is a problem where there is not sufficient airflow and the leaf falls then he bulb shuts off. My question is this: Why does it only shut off the bulb? Why not stop the projector and sound the alarm like the other failsafes? The reason why I am saying this is because all that happens is the bulb goes out and if you are on the other side of the booth checking out other things or are just simply working on something else then you have no idea what has happened until you see it which will depend on when you get done with your present task or when someone tells you. It may only be two or three minutes until you find out but that is two or three minutes that should not be wasted. Does anyone know of an upgrade/modification for this problem or if this is going to be changed on Christies new lineup.
Posted by Brad Miller (Member # 2) on 06-17-2002, 06:15 PM:
At least on the CA21 automation, there is a provision to have a sensor inside the bulb chamber that will stop the automation and sound the alarm if it does not light. You *could* always have your tech rewire that one switch in series through the failsafe, so that if the airflow switch is not closed, the system will think that the failsafes have dropped and stop the show and sound the alarm. The automation would also kill the lamp as well as raise the house lights.
Off topic, but sort-of related, I've set up a couple of private screening rooms that did not have any form of automation by wiring the lamphouse's interlock through a generic microswitch failsafe. The failsafe didn't read cues or stop the projector motor or really do anything, but if during the show the takeup belt broke, it would kill the xenon. That way there was no need to worry if the takeup was functioning. If the picture was on screen, the film was taking up, and it didn't require purchasing an automation system. 