8mm Forum: Elmo ST 1200 auto-thread hesitation problem

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Posted by David Kilderry (Member # 549) on July 09, 2010, 10:10 PM:

I swap projectors every now and then and placed my ST 1200 back in position and am giving my Eumig 940 a rest.

I have noticed that, even more than before, when I go to thread the Elmo by placing the film end in the front guide the film hesitates before it is taken by the sprocket.

I always trim using the Elmo trimmer, but this problem is getting worse. Once the film is grabbed by the top feed sprocket it threads OK.

I do not have another Elmo at present to compare to see if parts are worn or mis-aligned. Any ideas on this problem anybody?

David

Posted by Barrie Didham (Member # 1741) on July 09, 2010, 10:39 PM:

Yes David,i have this problem too and mine was near new when i got it.

Sometimes,if im not careful it can rip the first sprocket hole just before where it has been trimmed.

I wonder if this is more of a design fault?

Some film is fine and others a struggle with the ST.

Posted by David Kilderry (Member # 549) on July 09, 2010, 11:31 PM:

Yes Barrie, same happens on mine, it will tear that first sprocket if it does not catch it.

Posted by Roy Neil (Member # 913) on July 10, 2010, 04:22 AM:

If I had to guess I would wager the small green plastic guide may be 'worn' - allowing the film to move laterally perhaps ?

Check to see if a 'groove' has been carved the edge of the film as it passes through the plastic 'trough'

Posted by Rob Young. (Member # 131) on July 10, 2010, 06:47 AM:

David, my ST1200HD has always done this as well.

I always try to use white leader and it has become a matter of habit to check the leader as it emerges for the take up spool just to make sure the sprocket holes are intact.

Yep, every so often it will rip the sprocket holes and potentially leave a nasty bit of scratch worthy film in the path. If it does this, I manual unthread it, clean the path and load it again. Only takes a few seconds and doesn't happen that often, but certainly something I've grown used to looking out for on this projector.

Posted by Barrie Didham (Member # 1741) on July 10, 2010, 07:58 AM:

Roy,im 110% sure the plastic guide is not worn nor the small lug at the end,I had it apart today for a clean and its perfect.

I sure this has to do with the way the takeup sprocket wheel and guide has been made,it has to pull the leader up but most of the time cant get its tooth into the first sprocket hole on the leader,if you try and force it,it tends to rip that hole before it makes a catch and pulls it round.

It seems to be hit or miss with different leaders.

I did find that it helps to bend down slighty the first 1 to 2mm of leader before the sprocket hole,but even then it can still be a royal pain at times.

I,ve never had more then one hole ripped and there are no lines left on the leader or other damage i can see,so i have to rule out everything but bad design.

Posted by Gary Crawford (Member # 67) on July 12, 2010, 08:56 AM:

I noticed this problem to some extent on all my Elmo 1200 models....and the more curled the leader is the more problems I have. ( at least that's what it seems to me). Also that trimmer has trouble sometimes with newer polyester film stocks.... they just don't want to cut...tough. Fewer problems with my older prints.

Posted by David Kilderry (Member # 549) on July 12, 2010, 04:39 PM:

Yes Gary that trimmer really struggles with poly stock.

A flatter leader with less curl is sometimes better with feeding the leader in, but I notice that this sometimes then hesitates at the soundhead and makes the loop too large resulting in low sound with flutter and a subsequent re-thread.

Posted by Claus Harding (Member # 702) on July 12, 2010, 04:47 PM:

To add:
My GS grips fine at the initial feed but some films stop at the lower sprocket if the leader has too much curl.

Nothing much happens, the leader just piles up and escapes as intended before I stop it, but a little 'assistance' with the curved lower path sometimes makes it go through.

Par for the course, I think. It is after all trying to something automatically that was originally meant to be done by hand. My ST is actually more consistent in this regard than the GS.
Ah, an Elmo GS 8mm slotloader... [Big Grin]

One can dream.

Claus.

Posted by Graham Ritchie (Member # 559) on July 12, 2010, 05:28 PM:

What I do after trimming a film is to obtain the right amount of curl by pulling hard the first few inches of leader between my finger and the round shaft of a small screw driver, bending it one way or the other to form the right amount of curl. I have found "not to much" is just about right, its real easy to do and you can form a curl any way you like. I usually keep a small screw driver next to the projector just for that purpose.

Graham.

Posted by Rob Young. (Member # 131) on July 13, 2010, 05:19 AM:

Yes, I do a similar thing Graham. If there is too much curl I curl the first foot or so the other way and pull it into a tight loop between my fingers; end result is a nice flat piece of film to load which I find helps the film load through the path much more easily and not catch anywhere.

David, sometimes if the film catches at the soundhead or even second sprocket and the loop forms too large I stop the projector, ease the springloaded guide down from second sprocket and slip maybe two - three frames worth past the sprocket then re-start; usually the loop then re-forms just right and is easier than starting over again.

You know, it's funny since I've just got used to doing all this and never really thought about how fussy the trusty Elmo is to load properly, but I guess it is quite temperamental. I'd never load a film without having the side down and a keeping a close eye on it.

Posted by Tony Stucchio (Member # 519) on July 13, 2010, 07:29 PM:

So much for "auto" threading!

Posted by Bill Phelps (Member # 1431) on July 13, 2010, 08:16 PM:

Yeah...I also have the same issues with my ST1200...

Lets call it assisted manual threading. I also keep the side down to keep an eye on things. There is just to many precious prints running thru there not to!

Bill [Smile]

Posted by Rob Young. (Member # 131) on July 14, 2010, 04:54 AM:

"Assisted Manual Threading"!

LOL.

Perfect description [Wink]

Posted by Chip Gelmini (Member # 44) on July 14, 2010, 05:53 PM:

1. Looking at this problem we share with these machines, I wonder if sprocket tooth alignment is the problem. If you have ever removed the screw directly on the sprocket wheel, that screw removes a round disc about the size of an American quater. Under that, a sprocket ring with the super 8 sprocket teeth is removed. In theory, when this ring is reinstalled if it is not 100% exact position as it was before removal, simple unalignment could be the problem. So if you are going to remove this part of your machine, make note of position in the off mode before you do remove it, as to reinstall it identically.

2. One thing I've done is to remove a trimmer assembly from a dead machine. Actually, I removed the cover from the projector. Then, I cut out the trimmer from the cover, removing a piece of the cover while keeping the trimmer intact.

I then drilled two holes in this piece of the cover and mounted it with wood screws to the wall next to my crank rewinds. When trimming a reel before a show I do it off the rewinds not on the projectors.

Now you do not have to go as far as I have. If you have an extra machine with a spare trimmer, then put it on the shelf facing you so you have direct access to the trimmer from the front of the machine as compared to working from the side or rear.

Placement of this trimmer on the projector can be difficult to reach. If the film is not aligned correctly within the trimmer, then the cut is not proper and threading problems are more possible.

I cuation all readers they should NOT remove the trimmer from the projector directly, as these can be tricky to reinstall correctly. And, try selecting the earlier 180E or 600D to gain an extra trimmer via cover removal because the covers on these two units are plastic and will cut easier than the casted metal on the higher capacity machines.

My ST1200 models also hesitate on auto threading. But I rarely have the problem since remounting a spare trimmer.

3. While threading all of my machines, I make certain the cover is dropped down and the film path is exposed. I follow the leader as it goes through via autoload. My right hand is on the control knob, ready to stop the machine in the event of a jam. Only when the trimmed section exits the machine behind the lamphouse do I use my left hand to release autoload as included with most st 1200 units. At any point after that I stop to attach to the take up reel, whether using a stand alone machine normally, or with the arms down when the projector is installed on my towers.

4. I also gave up on using standard white leader for threading a long time ago. It doesn't matter who made it or where it came from. I do not use it, period.

Chip Gelmini

Posted by Paul Adsett (Member # 25) on July 15, 2010, 09:24 AM:

I agree with Chip that the white leader is pretty useless stuff It seems to break very easily and my GS just does not like it. I think Chip has resorted to old pieces of film for his leaders, which I think is a good idea for the first couple of feet, and then follow it by a length of black leader.
I do agree that the GS autothreading is not that great, and just look how complex that auto-threading system is - microswitches, relays, solenoids. Too many things can go wrong if there is too much curl on the leader. My Eumig 938 on the other hand always seems to thread flawlessly no matter what I feed it. Bottom line though is that I wish all my machines were manual threaders, like my little Bolex 18-5.

Posted by Barrie Didham (Member # 1741) on July 15, 2010, 10:50 AM:

Well from firsthand and what i have read here,i must conclude "Auto threading"was a type o in every ST manual or an optional extra no one paid for [Wink]

Posted by Chip Gelmini (Member # 44) on July 15, 2010, 01:34 PM:

Actually I use long pieces of super 8 polyester from faded non watchable optical films. I attach it to the regular print supplied leaders about 18 inches before the countdown. I am using extra length for Tower threading. The film when it leaves the machine must drop a good four feet almost to the floor to reach the Tower take up reel. This of course, is based on my set up here.

If you can purchase several thousand feet of unwatchable film for pennies on the dollar and make use of it, why not do it?

I also believe weather conditions play a large part of our troubles with autoload. Especially in cooler winter months. My projection room from late November through late April averages 60 degrees farenheit. Running the machines without film for about 5 minutes loosens everything up before threading. However in June July and August I merely turn them on and they're ready to roll without warm up. In wamer summer months naturally all mechanical parts inside are more flexible.

CG

Posted by Rob Young. (Member # 131) on July 15, 2010, 04:05 PM:

That is a great idea, Chip. As long as you have a nice, long, clean piece of film with which to thread up, why not?

Ironically, my Elmo trimmer will cut through just about any film stock.

It's the trimmer on my Beaulieu 780EL that won't! This machine WILL auto-load perfectly IF you give it the precise "Beaulieu cut" leader, which is a different shape to that required by the Elmo! [Roll Eyes]

And it will not cut through polyester!!

That's why I use brand new Kodak white leader (which I believe is acetate) because my both the Elmo and Beaulieu trimmer will cut it perfectly.

Since I run films on both my Elmo and Beaulieu 708, I find it easier to put Kodak white leader on my prints and let each projector trimmer "eat" at it every time I show it, then replace the leader if and when necessary. As long as you keep an eye on things, this seems the best solution for using prints on both machines.

And Chip, I also run my Elmo up for a good ten minutes before each show, which I also do out of habit, and yet your post has just reminded me that I actually, really, do that!!! [Smile]

Posted by Chip Gelmini (Member # 44) on July 15, 2010, 04:53 PM:

10 minutes seems a bit long, Rob, with all due respect even in cold weather. Unless you aren't running movies every week.

With a five minute warm up, I run just the fan for 2 minutes to flex the rubber belts and shutter shaft wheel bearings; then in forward mode for 3 minutes without film or lamp to loosen the gears and claw.

Summer time weather there's hardly any warm up required, the booth stays about 74 degrees this time of year June-July-August.

After I run a show, the small booth is above 80 degrees at the very end of the show. It's literally a walk in closet for space. Very tight. And there's at least 22 pieces of electrical equipment powered up for a given show, including everything that would be required based on my setup. Power strips, amplifiers; projectors, lamps; booth lights; rewind motors; drive motors; etc. I have two tower fans in the booth, one at the floor and one up high on a shelf for other circulation of air.

cg

Posted by Rob Young. (Member # 131) on July 15, 2010, 05:54 PM:

You're right Chip, 10 minutes is a long time; I just mean that I have adobted the habit of firing up the Elmo first thing when I know we are having a show.

Then it's time to sort out the reels, amplifier settings, play-in music, etc. by which time the trusty Elmo is hopefully all warmed up and ready to go.

That reminds me, one thing to watch on the ST1200HD is the rapid start-up device for the capstan roller. Since the Elmo capstan is not motor driven, this mechanism is supposed to run the capstan roller up to speed when you put the projector into forward.

I have it on good authority that this is a very unreliable bit of mechanics which often fails. Having had my Elmo serviced many times, sometimes you still have to put it into forward, then stop it, then re-start it a few times before the capstan roller will start to automatically spin. Of course, it doesn't matter once the film is loaded and running correctly, but if the capstan roller is already running, I've found it can greatly assist correct lower loop formation when you disengage the auto thread. [Smile]

Posted by Chip Gelmini (Member # 44) on July 15, 2010, 09:08 PM:

One possible quick fix:

As if you were going to remove the sound drum roller (but you don't really remove it)

Take a small phillips screw driver and give it a good spin before engaging threading. If the sound drum is coasting as you begin auto threading that could help give it a start up to speed

whereas after putting it in forward mode, the coasting helps the part you describe do it's job.

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