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Author Topic: Flicker in Cinemecannica Zenith x4000 Jeremy Fuentes Mmmm, Dr. Pepper! Posts: 1168 From: Corpus Christi, TX United States Registered: Jan 2004 posted 03-10-2004 09:20 AM                     I have a problem with a flicker in this lamphouse. Do you think it is the bulb or the lamphouse. Have not tried anything yet, and do not know the type of bulb that was put in there. The picture is also dark, so I am guessing its an old bulb. Any suggestions?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-10-2004 09:34 AM                     How many hours on the lamp and what type of rectifier, has the lamp been rotated? Those lamphouses produce a good light and usually long bulb life  |  IP: Logged Jeremy Fuentes Mmmm, Dr. Pepper! Posts: 1168 From: Corpus Christi, TX United States Registered: Jan 2004 posted 03-10-2004 11:32 AM                     Gordon, not sure, I'm not at the theater right now. But I am not even sure that the hours were even logged anywhere when the bulb was first installed. I wasnt working there at the time.  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 03-10-2004 01:49 PM                     I've had this same problem three times in the last 2 1/2 years. Once was the lamp. On the other two it was a diode going partially out. I had a heck of time the first time from never seeing it. The only way to find it was to check each diode with the rectifier on and with a scope to see which one was leaking AC. Definite qualified techs only job!  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-10-2004 01:51 PM                        If you don't know how many hours are on the lamp, how does the envelope look? Has it blackened much, or a lot, or not at all? How to the anode and cathode look? Are they pitted to hell?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-10-2004 02:14 PM                        Again, a quick and safe way to check for excessive ripple is to let some of the light "leaking" from the lamphouse shine on a silicon photocell with a resistive load, and look at the voltage output on a scope. Ideal is a "steady state" (DC) output. With experience, you can estimate the hours on a particular lamp by the blackening of the envelope, and the amount and type of pitting on the tips of the anode and cathode. (Use proper safety gear! ) http://www.film-tech.com/tips/XENONFAILURE.pdf  |  IP: Logged Gilbert Travin Expert Film Handler Posts: 101 From: Villeurbanne / France Registered: Jan 2004 posted 03-11-2004 03:21 AM                        I think as Larry and John : a partialy "out of order" diode make current ripple and flickering !  |  IP: Logged Jeremy Fuentes Mmmm, Dr. Pepper! Posts: 1168 From: Corpus Christi, TX United States Registered: Jan 2004 posted 03-11-2004 06:06 AM                     Thanks, guys. I havent had a chance to check the lamphouse again, since I have been off, and will be the entire weekend, but our tech is going to the theater tomorrow, and the problem should be taken care of by someone more experienced than myself. Thanks again.  |  IP: Logged Glen Rich Film Handler Posts: 55 From: Nedlands, Western Australia Registered: Feb 2002 posted 03-14-2004 02:43 AM                     It could be any of the above, check the rectifier diodes and the windings.If one of the windings of your rectifier is on the way out your tech. should find minor AC leakage coming from the rectifier to the lamphouse.  |  IP: Logged Jean-Michel Grin Expert Film Handler Posts: 222 From: Geneva & Lausanne, Switzerland Registered: Jul 2002 posted 03-15-2004 08:59 PM                        Hi ! Past six month a projectionist told me that he got a lot of flicker on the screen. I checked the rectifier: It was out of order: One selenium diode was burn out. I exchanged the all rectifier for a Irem recctifier, and all we be fine. Just check all diodes on Your Rectifier. Maybe one coud be shord-circuited, or burned out. Good Luck !  |  IP: Logged

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