Film-Tech Forum ARCHIVE: Sound problem

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Posted by Malcolm John Metcraft (Member # 2917) on 01-06-2008, 02:37 AM:

I have a 16mm set up in backyard, projection room built on back of house, screen near back fence cemented in ground so wind wont take it, speaker cables go under ground.
Come up behind screen, screen is 20 feet wide by 7 feet high and bottom of screen is 7 feet off ground so the average man can walk under without a sore head. Now for the sound problem coming from one of my projectors they are 2 Bell and Howell model 542 and one has a continues belling sound on every reel that's played on this projector, even run it with no film and even took out exciter lamp sound is still there any one know what mite cause this. Cheers [beer]

Malcolm.

Posted by Monte L Fullmer (Member # 2797) on 01-06-2008, 02:54 AM:

..wonder if the fotocell wires are touching the shaft of the flywheel and being cut by the flywheel causing shorting problems?

541's Autoload units?

Posted by Jonathan Wood (Member # 4614) on 01-06-2008, 03:08 AM:

When you say belling sound, do you mean like open mike feedback? No stray light is hitting or anything else interfering with the solar cell / diode ?

Posted by Malcolm John Metcraft (Member # 2917) on 01-06-2008, 06:51 AM:

Thanks Monte,
the models 542 with manual threading. I will disconnect photo cell wires and see if sound still I'll let you know.
the light travels threw a clear plastic strip to the back where the tiny little Like a miniature lamp with a sail in it with 3 wires attached.

And thank also Jonathan,
No it dozen t sound like Mic feedback it sounds more like metal scraping on metal I'll disconnect wires maybe the plastic strip is rubing on sound drum where film sound runs ?? Know that's wrong because I run projector without film so sound drum and fly wheel dozent spin the belling metel sound was still there. [Frown]

Malcolm

Posted by Malcolm John Metcraft (Member # 2917) on 01-07-2008, 12:47 AM:

Today I Disconnected photo cell and exciter lamp & run projector with no film the belling sound is still there, could this sound be caused by the main drive motor it is rubber mounted with clamps.
this noise is every noticeable in back ground of the movie.
I have made a 60 second recording off this belling noise but how can I put it on the site so you all can listen to it.
or should I just replace it with another projector. [Confused]

Malcolm

Posted by Richard Fowler (Member # 893) on 01-07-2008, 10:10 AM:

Not sure if this is a tube amplifier model...if so you may have a "microphonic" tube causing the ringing sound.

Posted by Cameron Glendinning (Member # 3516) on 01-07-2008, 02:31 PM:

No advice on your problem, but Ive included a shot of wagga wagga drive in, form the early 90's, incase it was part of your inspiration.

Posted by Malcolm John Metcraft (Member # 2917) on 01-07-2008, 11:59 PM:

Thanks Richard,
and yes they are tube Amps, I will switch valves with other projector just to see if it is a valve problem the other projector runs fine will let you know. Malcolm

and in answer to Cameron's Question

thank for that picture you brought back great memories as I use to work there in 1969 to 1983 when Hoyt's theaters own it then they sold it to Village theaters about 1975.
I use to do the daily show at Hoyt's Plaza theater and night shows at drive-in great times one night halfway threw a movie we saw something on top of screen sum one had climbed up the back of screen and hung from the top Manager and car hobs running wondering how they would talk him down police arrived and he climbed back down and movie never stop one the show must go on. Except for fog or wind taking sheets of the screen. Great memories. All those years working there and I did not get any pictures of the place I thought it would be there for ever now it's home for a nursery for plants / car sales/ boat sales/ ?? thanks for pic. [Smile]

Malcolm.

Posted by Malcolm John Metcraft (Member # 2917) on 01-09-2008, 03:00 AM:

Hello Gain,
That's to all you guys for your help with my sound problem thanks to Richard Fowler you where wright it was one of the tubs a Bell and Howell 25C5 tube “ valve” made in the USA.
The projector is about 40 years old and the tubs most likely been in it cents new they are bit black in side the glass.
I don't think electronic store would sell them any more. [thumbsup]

Malcolm