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Topic: Century SA gate closing problem

John Westlund
Expert Film Handler

Posts: 204
From: Burney, CA, USA
Registered: Jun 2001

posted 10-23-2002 09:16 PM

Im having a problem with the gate closing on a Century SA. The gate closes very slowly. The problem is not the spring in the handle, but it is that where it fits into the lens holder casting, it has been oiled and greased sometime in the past. The oil and grease have turned into a build up of gunk that need to be removed. So the question is, how do i get that part out so that i can clean it?

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 10-23-2002 09:23 PM

If you are speaking of the part I think you are speaking of, look on the side for a small allen screw.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 10-23-2002 09:29 PM

John, Its possible that the lens barrell that slided in anbd out is suffering fomr the goobered grease syndrome. With the knob off the lens mount assy try to move it in and out by hand. If its sticky it'll ahve to come out abd be taken apart and cleaned. If you've never done this it can be a bit tricky to get it back in correctly. Look in the Century SA manual here on film-tech for those instructions. I believe they are in there. The main thing is that the gap between the face of the plate that the curved runner mounts to and the lateral guide on the trap has to have about .28" clearance for film tension to be correct. I sometimes stack feeler gauges to do this, or as I did later on I ground a gauge that I carry with me to this day in my service box. A piece of drill rod very close to that thickness will also suffuce.
I just checked the manuals section and its all in the 1975 printing of the SA manual.
Mark @ CLACO

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Barry Hans
Film Handler

Posts: 92
From: Minneapolis, MN, USA
Registered: May 2000

posted 10-24-2002 10:35 AM

To do it right it needs to be taken apart like Mark said. I have used spray lubricants like triflow or liquid wrench to free up sticky mechanisms. Pull the lens and spray in between the lens holder casting and the gate assembly from the lens end and moving it back and forth by hand, you can get it freed up. The spray lube will brake down the hardened grease. Use a lot of rags to catch the lubricant and gunk and wipe out the head well afterwards.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 10-24-2002 02:54 PM

No, I would disassemble it. Using a spray cleaner or lubricant may help you in the short term, getting a show up and running in a pinch, it will likely cause MORE trouble in the long run.

Yes, do whatever you have to (within reason) to keep the show going but at the first convenient juncture the lens barrel/gate mechanism should be taken out and cleaned with an appropriate solvent to remove all the baked-on GACK that has a tendancy to build up in there over the years.

Using a spray will loosen up the mechanism,for now, but once the solvent has evaporated the grease, etc. will start to harden up again, leaving you back in the same place you were when you started. This time it just might be WORSE. Aside from that, any residual solvents that may have spashed around in there or any vapor from the spray could cause damage if it gets on the film.

I have an old Century in my basement that I tinker around with from time to time. (In hopes of getting it running some day.) From my experience, if you work carefully it's not too hard to take it apart.

The parts diagram from the manuals on this site will help you with the disassembly/reassembly.

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 10-24-2002 03:14 PM

I'll side with Randy & Mark on this one. It's not too bad an assembly to take apart if you take your time, and cleaning the goop off likely clears the problem up. Watch the adjustment of the upper guide to be sure you're properly entered on screen.

Pat

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Steve Guttag
We forgot the crackers Gromit!!!

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

posted 10-24-2002 05:25 PM

Also look for burrs on the slot the gate closer rides in. When they burr up they will start to drag a bit. Have a file and emory paper handy.

Steve

------------------
"Old projectionists never die, they just changeover!"

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John Westlund
Expert Film Handler

Posts: 204
From: Burney, CA, USA
Registered: Jun 2001

posted 10-24-2002 08:03 PM

Thanks guys. I ended up taking it apart today and cleaned it out really well. It did take me a little while to get it just right but it works great now.

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