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Author
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Topic: Projector runs too slow
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Christian Bjorgen
Jedi Master Film Handler
Posts: 996
From: Kvinnherad, Norway
Registered: Oct 2009
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posted October 18, 2009 06:04 AM
As I was watching my Star Wars 200' reel the other day, I noticed that the sound was "slowed down", making the voices very deep and slow-motion-ish. However, it wasn't noticeable on the video itself, only on the speech.
So, I figured it was probably because I hadn't warmed up the projector prior to use, and didn't give it anymore thought.
However, I tried it again today, and let the projector warm up for nearly 10 minutes (manual says 90-120 seconds is enough).
The video looks fine, but the music/speech is slowed down, so I'm thinking it runs at maybe 2-3 fps too slow.
Any ideas?
I made a recording of it that I can upload if you want to see the problem yourselves.
--- UPDATE ---
I opened up the projector to clean it, thinking maybe it was dust, and I found about four feet of shredded film here and there, stuck between various parts. Gonna test it once the electronic rinse-spray dries up.
--- UPDATE 2 ---
Tested now, still slow audio. The cleaning did however improve my picture quality alot. Any ideas?
[ October 18, 2009, 09:28 AM: Message edited by: Christian Bjorgen ]
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Well who’s on first? Yeah. Go ahead and tell me. Who. The guy on first. Who. The guy playin’ first base. Who. The guy on first. Who is on first! What are you askin’ me for? I’m askin’ you!
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Jean-Marc Toussaint
Film God
Posts: 2392
From: France
Registered: Oct 2004
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posted October 28, 2009 01:46 PM
Great.
OK, pic 4, below the 50/50hz cycle change part, you see two discs over the transformer. The drive system is that tiny pulley between both discs. You want to concentrate your cleaning/sanding efforts on these two parts (pulley and disc). Be gentle. Run the projector without any film, dust and clean the area, sand the discs, clean the area, sand the disc, clean the area, and so on and so forth. Go through your films and use something like a sound 50ft reel that you don't really care about as a test reel. See if the speed improves.
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The Grindcave Cinema Website
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Martin Jones
Phenomenal Film Handler
Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008
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posted October 29, 2009 11:07 AM
Christian,
The 50/60 Hz switch on these machines is NOT an electrical switch at all, so the mains frequency is not important.
It is a MECHANICAL adjustment that alters the travel of the main drive ball on the motor shaft. This then shifts the speed RANGE of the machine by using different diameters on the drive plates.
The lever should move easily into the other position (according to the Manual!).
For those who would like to make a precise calibration of the operating speeds of 8XX machines (perhaps following lubrication or an overhaul) I have taken the liberty of re-printing another Member's instructions below. I apologise for not giving a credit for this, but I cannot now locate the source!!...
"The speed range of the Eumig 8XX is set by a large, shiny-metal screw just above the shaft that carries the two rubber-faced drive disks. This runs through a slot in black metal plate through which the 50/60 Hz switch passes. It clamps a shiny-metal bar through another slot. The further down this bar is, the faster the projector will run. Usual top speed is in the range 27.5 to 28 fps.
Adjustment of speed requires the use of a suitable meter: either a true r.p.m. indicator (measures the interval between pulses from the sensor) or a digital frequency meter (measures the number of pulses in a given time). The adjustment is very delicate; speed is extremely difficult to set by ear alone. I would not recommend attempting this adjustment unless you have the correct equipment and tools, and are used to using them.
Measure the speed with the projector running forward, with the lamp on, and with the take-up spool spigot clamped stationary to simulate a film load.
Examination of the metal bar below the clamping screw shows that there is a small hole in it below the slot. Once the speed-measurement equipment has been set up, and with the projector UNPLUGGED, set the speed control lever into a mid position. Insert a suitable instrument screwdriver in this small hole and hold it in place. Then, with a thin, but broad screwdriver, slacken off the adjustment screw no more than a half turn. This should allow the slotted bar to be moved UP slightly. (Movement of this bar about 2 mm covers the entire range of speed between about 23 and 28 fps, so only a slight movement should be made between speed measurements.) Now, tighten the adjustment screw, set the speed control lever to 24 fps and measure the speed. Repeat this adjustment until the required speed is attained.
Finally, check that both the 24 fps and 18 fps speeds remain correct. It is a good idea to check this in the 60 Hz (or 50 Hz if you a running on 60 Hz) position of the switch, checking that the speed corresponds to the ratio of the frequencies.
These instructions are based on my examples of Eumig 8xx machines. Eumig were fond of making minor changes during production, so check your machine before starting."
Thank you, (whoever you are!)
Martin.
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Retired TV Service Engineer
Ongoing interest in Telecine....
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