my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » How To Eliminate Buzzing?

Author Topic: How To Eliminate Buzzing? Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 10-04-2005 01:20 PM                     I've almost retroffited all projectors with RED LED Readers. 2 have not been retroffited because of budget for now and I always had this problem. Humming/Buzzing! Case No.1: ---------- Smart MOD6 processor Cinemeccanica V4 projector Kelmar Stereo Sollar Cell When lamp is on, even if no film is on projector I have humming and buzzing from the speakers. I have checked for grounding and both the rack and the Projector are grounded properly. Also the processor is grounded properly. I have tried "ungrounding" the processor, rack, projector in several combinations but I was never able to eliminate it completely just reduce it a bit. Any ideas? Case No.2: ---------- Unknown Brand Mixer-Preamp with Phono Capabilities Lexicon Home Theater Processor Several Amps! Cinemeccanica V8 Projector Kelmar Stereo Sollar Cell Same situation as Case No1. When exciter lamp is on, humming is heard. Tried several ways of grounding the components and checked for proper grounding and it appears ok. I was never able to eliminate the humming again but just lower it. The Sollar cell is connected on the Phono Inputs of the mixed (phono 1). So. Any ideas?  |  IP: Logged Bruce Hansen Jedi Master Film Handler Posts: 847 From: Stone Mountain, GA, USA Registered: Dec 1999 posted 10-04-2005 06:39 PM                     Have you checked the filter cap in the excitor power supply? Block the light from the cell, and see if the hum goes away. If so, try swaping the supply with a known good one. Is there stray light getting into the cell from the room, or a threading lamp?  |  IP: Logged Floyd Justin Newton Jedi Master Film Handler Posts: 559 From: Phoenix, Arizona, USA Registered: Jun 2002 posted 10-04-2005 06:44 PM                     Ground loops?  |  IP: Logged Ron L. Funderburg Film Handler Posts: 6 From: Goodwell, Oklahoma, USA Registered: Aug 2005 posted 10-06-2005 12:35 PM                     If the red LED is not in the right alignment, you can buzz or hum from that as well. The light to high or low will give you a stray light buzz not sure if left or right can affect that. I had a reverse scan problem that was driving me nuts (because an employee must have tried to adjust it) we had a popping in perfect rhythm. It was the sprocket wholes but at the time I found it (after midnight and several complaints) my mind wasn’t working right so I didn’t jump on it right off. Well I looked everything over for a good hour before it dawned on me. When I pushed the light side back in a fraction of a fraction the volume jumped up and the popping dropped out. I then put the oscilloscope on it and made the proper adjustments and it is fine. At least until some over curious projectionist plays again.  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.