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Author Topic: Slow Projector
William Phillips
Expert Film Handler

Posts: 117
From: Cardigan, Wales, UK
Registered: Feb 2002


 - posted 07-23-2006 03:03 PM      Profile for William Phillips   Author's Homepage   Email William Phillips   Send New Private Message       Edit/Delete Post 
One of my projectors runs a bit slow, a film that runs 2hours 30 on another machine will run 2hours 34mins approx on the slow one.
I have got an inverter on the machine so can speed it up. How much in frames per second should I increase it??
Projector is a Cinemeccanica 5B-4000

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 07-23-2006 03:18 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
You will need a stopwatch and exactly 45 ft of junk film. Adjust speed to have the splice occur every 30 seconds. Allow to run for several minutes.

Method #2: 1000 hz sound loop and frequency counter.

Method #3: use a strobe with digital readout: set for 1440 flashs per minute. Speed of shutter is 1440 rpm. Louis

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Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 07-23-2006 03:22 PM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
1 frame per second increase will probably do the trick. Sounds like it may be running close to 23 frames instead of 24 frames per second.

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William Phillips
Expert Film Handler

Posts: 117
From: Cardigan, Wales, UK
Registered: Feb 2002


 - posted 07-23-2006 03:48 PM      Profile for William Phillips   Author's Homepage   Email William Phillips   Send New Private Message       Edit/Delete Post 
Cheers guys,
Its been bugging me for ages. I could never decide if one was fast or the other slow. The slow machine has got a 2 blade shutter and there is a bit of flicker on screen, its just visable. The other machine has a 3 blade, so no flicker at all. It got to the point where i swapped the shutters over to see if 2 blade still flickered on other machine and no. So thats how i came to the conclusion that my machine is slow. And now thinking about it I am going to build a sprocket hole counter as of course it sould be 96HZ [Roll Eyes] While im at it should make a milage counter to see how much they do a year [Big Grin]

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
Registered: Sep 2000


 - posted 07-24-2006 07:04 PM      Profile for John Anastasio   Author's Homepage   Email John Anastasio   Send New Private Message       Edit/Delete Post 
Or you could figure it in furlongs per fortnight!

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Marc Hansen
Film Handler

Posts: 93
From: Seattle, WA, USA
Registered: Dec 2000


 - posted 07-24-2006 10:11 PM      Profile for Marc Hansen   Email Marc Hansen   Send New Private Message       Edit/Delete Post 
John-
I had a physics prof in college (Strieb I think, it was 30 years ago) that used furlongs per fortnight at every chance he could. I've never gotten it out of my mind. You didn't take classes from him did you? I almost never hear it used.
Marc

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 07-24-2006 11:59 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
We had that in high school back in 1964 in Louisville KY. Louis

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 07-25-2006 09:09 AM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
I use 6, 9 or 10 foot loops, exactly down to the perf, and then run the film, count the splice clicks thru the gate for 30 seconds or a minute and then do the math in my head. 10 Feet = 9 clicks per minute, etc.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 07-25-2006 10:25 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I much prefer the strobe route...not only will it tell you speed pretty darn fast without the math...it also is useful to check on other problems in the drive train.

Steve

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999


 - posted 07-31-2006 11:09 AM      Profile for Frank Angel   Author's Homepage   Email Frank Angel   Send New Private Message       Edit/Delete Post 
Wasn't there a file posted somewhere here on FT that you could print out which contained an image of a round strobe wheel that you could stick to one of the sprocket drives to read speed? Or am I dreaming?

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 07-31-2006 12:46 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
quote: Frank Angel
Wasn't there a file posted somewhere here on FT that you could print out which contained an image of a round strobe wheel that you could stick to one of the sprocket drives to read speed? Or am I dreaming?

You're thinking of the segmented disks that were used to checking the speed of record turntables, where a simple 60Hz neon "strobe" was used to illuminate the disk. But a projector shutter shaft is likely too fast (1440rpm) for that technique to be accurate.

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Ron Yost
Master Film Handler

Posts: 344
From: Paso Robles, CA
Registered: Aug 2003


 - posted 07-31-2006 01:18 PM      Profile for Ron Yost   Email Ron Yost   Send New Private Message       Edit/Delete Post 
Frank, Yes there was a pic of a strobe dial posted .. I have it, but can't remember who made it. It's called 'dial.jpg'. Do you want it? If I could remember my password [Eek!] I'd upload it again. I pasted it on a sound sprocket in my 9030, just for grins. Seems to work fine, tho my machine is running just a tad slow according to the 'dial'.

Ron Yost

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 07-31-2006 02:23 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Thanks. The shutter shaft may be too fast for a disk method (1440 rpm), but a 16-tooth feed or holdback sprocket rotating at 360 rpm might be within range when illuminated by a simple 60 Hz strobe.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 07-31-2006 07:10 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
quote: Steve Guttag
I much prefer the strobe route...not only will it tell you speed pretty darn fast without the math...it also is useful to check on other problems in the drive train.

I have a General radio Strobe thats crystal refrenced which I've had for many years. I actually use quite frequently. I originally bought it for checking for film flutter in my 8 perf projctor and speed accuracy on my 8 perf camera. Recently it helped us big time on solving a Simplex 1060 scratching problem. you couldn't see it scratch film with the naked eye but the problem was very easy to see happening with the strobe. I would also rececomend the use of a direct reading digital tach. on the shutter shaft. These are fairly inexpensive if you search them out... but not useful for finding scratching problems.

If worse comes to worse you can only allow slow audiences in that house.

Mark

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David Favel
Jedi Master Film Handler

Posts: 764
From: Ashburton, New Zealand
Registered: Feb 2002


 - posted 08-01-2006 06:01 PM      Profile for David Favel   Email David Favel   Send New Private Message       Edit/Delete Post 
I have inverters with the paramaters able to be observed and changed on a detachable faceplate.
All I had to do was change from 49 to 50 Hertz

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