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Author Topic: P35GPS Dowser Question Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-26-2006 12:38 PM                     When we rebuild or overhaul a pro35 we put locktite on the threads of the changeover so it can't vibrate loose otherwise they are very reliable  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 08-26-2006 05:35 PM                        Let me switch gears here for a second (even thought you guys are having so much fun with dowser/douser semantics).... We have a video projector that is used as if it were another projector equal to our 35mm machines, i.e., we often go back and forth between film and video in the same program (just LOVE those festivals). Now the problem, as everyone knows, is that in the video world there is no such thing as "black" coming out of a video projector; there is always a goodly amount of unwanted light if nothing short of the vprojector's bulb being extinguished. So here's this big bluish-gray square in the middle of the 35mm image when I go from video to film. My only option now is to run over and stick a piece of cardboard in front of the video projector lens, not exactly an elegant solution (nor a pretty sight). Plus I don't exactly like having to abandon from my 35mm projector the minute I start it. I want to build a simple dowser unit that I can just sit in front of the video lens so that when I changeover to the 35mm machine, it pulses the blade down and blocks any residual light. Simple enuf, but can anyone recommend which standard, off-the-shelf changeover unit has the longest armature travel? Those video projector lenses are BIG. I know I can probably extend the arm of say a Kelmar, but I don't want to start messing with the balances that might cause it to be sluggish or maybe not pull up or down properly. Or, if I have must add an extension, whatever unit would need the shortest added extension would be the one to use. I am surprised that now with all the vprojectors in use that don't have any internal dowsers and with all that light spill, someone hasn't made a simple stand-alone changeover unit that you could just stick it in front of any projector that needs one. The guy who I worked with this summer who was the video projectionist was forever doing the "Hand in Front of the Lens" dowser method when one of those stupid setup menus would unexpectedly popup. If we had one of the changeover units I am contemplating, it would have prevented lots of cursing, plus of course, one's hand rarely fully blocks all the light, so when all that gack decides to project in front of an audience, the hand doesn't quite do it. Besides, it LOOKS like someone is sticking a hand in front of the lens....not what you could call top-notch presentation, eh?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 08-26-2006 11:31 PM                     Frank, I have two theaters that I have set up exactly in the fashion of what you are asking for. You want to buy the Kelmar electric changeover kit for CENTURY JJ projectors. You can either wire it totally seperate from the 35mm dousers, or you can cross-wire it. Since you run changeover, it would make more sense to me to have your own specific set of momentary pushbuttons to open/close the video projector douser though. Mine are mounted on the top of the port window frame, however in one auditorium due to the forced odd placement I had to build a little projector shelf that had the douser laying on it's side. So long as you build a "track" for the douser to slide in, it works fine and dandy moving from left to right. If you mount the dousers in the normal fashion, gravity will do just fine and you don't need any kind of track.  |  IP: Logged Raphael Friedland Film Handler Posts: 37 From: Raanana Israel Registered: Nov 2005 posted 08-31-2006 10:45 AM                     Look for "smart glass" in the internet  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 08-31-2006 11:42 AM                        Better yet, get a video projector with a mechanical changeover douser that actually does completely block the light from hitting the screen. The Panasonic 7700 and some Christie model definitely have this feature and can be connected to any sort of automation system (or footpedal!) that you may want to use.  |  IP: Logged Carey Barber Expert Film Handler Posts: 143 From: Newport News, VA, USA Registered: Jan 2003 posted 03-04-2007 02:05 PM                     I received and installed the Dowser Retrofit Kit about a week ago. I have tried pretty much every tip that has been given to me for maintaining the old dowsers and they always eventually fail. The same goes for replacing parts. It looks like this retrofit is the best and permanent solution. From what I have seen, this is a much better design and it looks like it won't have any problems. (It has only been in for a week, so time will tell here...) The dowser moves side to side instead of up and down. You will use the same solenoid assembly but most of the stuff behind the film gate (the air shield, baffle, etc.) will be replaced. For anyone interested: Dowser Retrofit Kit (for Christie P35) Part # 107-108001-01 Price - $165.00  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-04-2007 05:08 PM                     While the new dowser retro is a good idea since it will take the heat better the big problem at hand was not corrected and that is the rediclous C/O coil location and the pain in the ass it is to change them out... it is an absolute joke. Anyone who has had to change them out I'm sure will agree. Christie at the same time should have gone to a rotary solenoid and gotten rid of the cheapo c/o coils they use. Mark  |  IP: Logged

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