This is topic ST1200HD question in forum 8mm Forum at 8mm Forum.
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Posted by Jim Schrader (Member # 9) on May 18, 2007, 09:28 AM:
Upon inspecting my machines I have 2 I noticed on the shutter of one that it has a piece of stainless steel screwed to it and the other does not was there a reason for this? I am trying to upload some picture to show if not i will email them to who ever can help.
Posted by Jim Schrader (Member # 9) on May 21, 2007, 09:21 AM:
appaerntly no one cares
Posted by Graham Sinden (Member # 431) on May 21, 2007, 11:39 AM:
Jim,
When you say on the shutter wheel do you mean around the edge. Because someone may have removed the rubber strip which melts and replaced it with a bit of metal so it runs at the correct speed. Just an idea.
Graham
Posted by Hans van der Sloot (Member # 494) on May 21, 2007, 11:47 AM:
Hello Jim,
Can you upload some pictures, so I can compare it with mine ST-1200HD?
Posted by Jim Schrader (Member # 9) on May 21, 2007, 12:32 PM:
I have tried to post pictures but it never works i get this message "Your login has failed! Please check your username and password and try again.
well if i am able to post this message how can my login fail?
i will email you both the pictures
Posted by Chip Gelmini (Member # 44) on May 21, 2007, 02:16 PM:
Hi
I think Gramham is right on that guess. I have an ST1200HD with optical that seems to run slow. It does not have the rubber on the shutter - it does not seem to have some type of replacement ring for the rubber that melts. One way to look also is the sound drum. There are two types of brass attachments of the sound drum. One type is flat right where the phillips screw mounts and holds it tight to the flywheel shaft. The other is deep inside just a bit compared to where the screw holds it to the shaft. This is hard to explain and maybe understand, but that's the best I can tell you.
CG
Posted by Jim Schrader (Member # 9) on May 21, 2007, 02:39 PM:
Hello all, this plate is attached to the flat side of the shutter this shutter originally had the rubber which melted while watching a film i managed to shut it down before it got to messy and clean it up and remove the rest of the rubber from the shutter it runs fine bt needs a small adjustment for the 18fps which is maybe why the rubber was put on in the first place?
Posted by Kevin Faulkner (Member # 6) on May 21, 2007, 04:14 PM:
Jim Elmo produced some of the ST1200HD's with the rubber so its not been added by anyone else.
I cant make out what this part is that you are describing ![[Confused]](confused.gif)
To put pics on the forum you must use exactly the same username and password you use each time you log onto the forum.
If you have any more problems then email the images to me and I'll put them up here for you. super8 at mrelmo do co dot uk
Kev.
Posted by Jim Schrader (Member # 9) on May 21, 2007, 06:04 PM:
kevin i have email these pictures to you also hope these help
Posted by Hans van der Sloot (Member # 494) on May 22, 2007, 02:19 AM:
I got some pictures from Jim and will put them here.
It seems you have a adjustable shutter in your Elmo.
Posted by Jim Schrader (Member # 9) on May 22, 2007, 08:22 AM:
why would one use this?
Posted by Chip Gelmini (Member # 44) on May 22, 2007, 04:54 PM:
In theory, of course............
With 35mm projectors, there is usually a way to adjust the shutter timing to reduce "ghosting." These simple fixes on theater machines is nothing more than a knurled knob with an indicator point. When the problem is severe, then access to the blade with more accurrate adjustment can be performed. On a theater machine (again 35mm) you advance the picture frame 1/2 way down on the movement stroke (i.e. film claw to the 4 perf movie frame). On the Century "C" and "J" line of machines, a knotch on one blade of the shutter was aligned to a indicator point inside the sight glass of the picture head.
"Ghosting" - is when the shutter is not fully closed as the picture frame advances at the rate of 18 or 24FPS. Because the light is exposed and the film is advancing, the movement of the still frame is streaking. Bright street lamps for example, would appear to have alittle of that light directly above them. Sort of a trick to the eye vision - such as perfectly round circles (such as lab cues in the upper right hand corner) are naturally round but when projected with scope lenses they are vertically egg shaped.
Only when the shutter is 100% open at precisely the same time that the frame of film is 100% frozen in time will you not have ghosting.
As I said in theory this might have been a prototype adjustable shutter blade in your ST1200 and if I am right about this I would say this is a marvelous thing they put in to such a great machine.
But I would speculate here and please DO NOT go try to adjust it especially when this kind of thing represents shutter blocking light while the frame advances. In this manner adjusting this would NOT repeat NOT pick up the speed of your machine. If slower speed is a problem, then you need to address why it is running slow.
I would assume that (1) kevin Faulkner could address the reasons of your shutter blade in the ST1200HD; and that (2) Brad Miller could enlighten all of us alittle more on Ghosting but I do feel I have part of that right in the explanation.
Regards,
Chip G
Posted by Jim Schrader (Member # 9) on May 22, 2007, 08:32 PM:
thanks chip i had no plans on moving it ![[Smile]](smile.gif)
just curious why one had it and not the other arethere date codes on these machines to tell when they were manufactured?
Posted by Kevin Faulkner (Member # 6) on May 23, 2007, 04:44 AM:
As I said to Jim in a PM to him direct I have never seen this on an ST1200HD before so cant say if its one that Elmo included or was put on by someone else.
Your explanation of ghosting is spot on Chip but you wouldn't have to go to these lengths on the 1200 unless this shutter has been designed with slightly narrower blades to let more light through.
Jim can you see if these blades are narrower than on your non modified machine?
I take it this machine still has 3 blades or does it have 2?
Kev.
Posted by Jim Schrader (Member # 9) on May 23, 2007, 08:55 AM:
Let me look at hese again to make sure
Posted by Joerg Niggemann (Member # 611) on May 23, 2007, 03:34 PM:
The "adjustable shutter" seems to be an original Elmo part. I saw it in another ST1200 D, but I can't imagine any technical reason because the second shutter blade is fixed to the first one.
Most Bauer machines have a variable second shutter. The first one is optimized for a maximum light output in forward mode. Because of the phase difference of claw and film movement between backward/forward mode, the "forward-optimized" shutter has to be closed for a longer time when projecting backwards to avoid ghosting. This is achieved by the second shutter which is applied in backward mode only.
Joerg
Posted by Graham Ritchie (Member # 559) on May 27, 2007, 12:41 AM:
Interesting, but considering the speed the shutter is rotating at, would this not put the shutter out of balance with a resulting vibration felt through out the projector.
Graham.
Posted by Tony Milman (Member # 7) on May 27, 2007, 10:36 AM:
Jim
What is your machine serial number?
Posted by Jim Schrader (Member # 9) on May 27, 2007, 05:06 PM:
406157
Posted by Jan Bister (Member # 332) on May 28, 2007, 01:07 PM:
Graham: both the fixed and variable parts of the shutter are balanced (each has 3 narrow blades that can either match to let more light through or partially overlap to form wider areas of coverage=more time for the claw pull-down to occur)... so no, mass imbalances and thus vibration do not occur.
Posted by Jim Schrader (Member # 9) on May 29, 2007, 08:49 AM:
so by adjusting this one would not be able to do any telecine transfers?
[ May 30, 2007, 06:54 AM: Message edited by: Jim Schrader ]
Posted by Don Huber (Member # 828) on May 29, 2007, 11:46 PM:
Finally can post! Hello to all. Got my dad's St1200hd. Sucker has hardly been used but wasn't working, belts were rotten. I was hoping to get it to transfer my family's film to dvd So I got a hold of a person that sold belts. He said there was a pot inside that could be adjusted so I bought all new belts and replaced them only to find out that the pot did not exist and that this unit was a no go for speed adjustment. Bummer. Got the goo still on my fingers from two weeks ago. LOL
Aside from all that, My unit appears to have this type of shutter wheel as well. Serial no. is 406765.
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