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Topic: Elmo ST-800 Belt Replacement & Film Feed Problem
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Paul Browning
Phenomenal Film Handler
Posts: 1006
From: West Midlands United Kingdom
Registered: Aug 2011
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posted February 04, 2012 08:23 PM
Hi Janice, i've looked at your video footage and tried to reproduce what your getting with my st800.I have it stripped to about the same as your's.Ok, first off the lever in video 2 and the part mating with it ( the bit your trying to move) are in the vertical position when the function switch is at rest,so in my opinion its in the right place,look at at this now does it look like its in the 12 o'clock position in your video it does to me, secondly both of these mechanism's move backward and not forward ,that is, when function switch is in the 'F' position it move's only a fraction ( possibly 10 thousanth's of an inch)in a backward direction,then when switch is now moved to lamp position it move's backward almost in line with the square casting jutting out from above.Now when the function switch is moved in the reverse position both the lever and the part your trying to move do not move at all.Ok, if you go to the other side of the machine where the sound head is and the chute's that guide the film ,do this, tare a small strip of news paper about the width of your little finger and about as long and carefully place it between the sound head and the presure pad, its directly above the soundhead on the bit you showed in an earlier video moving in and out with your thumb,with the function switch in the 12 o'clock position this paper should just slide in ans out with no dragging felt on the paper.If you now move the function switch to 'F' and leaving the paper between the sound head and presure pad you should feel a tiny bit of dragging where both the soundhead and presure pad are actually gripping the paper.Now reading one your uploads earlier you seem to have the impression ( correct me if i'm wrong here)that the soundhead move's, well i'm 100% certain it does not ,its fixed and only the presure pad mechanism's that sits directly above it move's down to it keeping the correct pressure on the magnetic sound stripe at all time's.All this info janice is gleaned from my st800 that works correctly i'm no expert on projector's but i am an engineer and i'll do my best to help you or anyone else on this forum regardless if i can.
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frank arnstein
Jedi Master Film Handler
Posts: 534
From: Gold Coast. Australia
Registered: Jan 2005
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posted February 05, 2012 04:17 AM
Hi Janice,
Re..."Pat, I think you and Frank are in agreement with me that something needs to push that pivot rod further to push up the chute to the proper height for the film to feed."
This statement is not really correct because I am in full agreement with Paul who has said the selector shaft needs to move back and not in the direction you were pushing it with the screwdriver. That is the wrong direction. You want the chute and sound head pads and the roller that drives the flywheel to fully close when switched to forward/lamp/sound, so it must go in the other direction.
It is in the off position that there should be maximum gap at the sound head. When you go to F, the gap will close a tiny, weeny bit but still be open. Then finally all gaps fully closed when switched to forward/lamp/sound.
When good quality film is being threaded it will emerge from the film gate and go down, not like Janices picture of the white leader which is curling to the right and will miss the chute. Its a bit like shooting a bent arrow. I did say earlier to check for "no curl in the leader" and get rid of the white leader if it wont go straight down.
There are 2 devices to direct the film into the sound head gap. One is the long "angular down ramp" which starts as soon as the film comes out of the gate and passes over the top of the black plastic loop former rod. The film will turn outwards to follow the ramp down towards the sound head pickups. Halfway down the ramp it becomes trapped by a plastic wedge above it that wont allow it to move upwards and helps aim it straight at the sound head gap. Even if there is a small gap of less than 1mm at the sound head/pads the film will go through the gap OK if its straight and flat film. Same for the flywheel roller. Minimal gap needed. There is no need to lift the chute up high when hand testing it because it doesn't go that high when in operation. It has to only go high enough to lift the pressure pads off the sound head.
So to sum up, I feel there may not have been anything wrong at all with the machine. The fault appears to have been the film curling excessively. Elmos don't like curly leaders at all.
Janice, try to set the tang back to where it was, it should be horizontal and level and then try threading again with straight film.
Do not switch the selector knob to lamp/sound/on until the film has fully connected onto the lower sprocket or it will get jammed when the sound head and flywheel rollers close their gaps. It needs the lower sprocket to drag the film through the closed rollers or they will stop the film there and a bunch up will occur.
Paul, you were quite right about the terminology error. When we were talking about the sound head moving, we were really meaning the sound head pressure pads. Of course the sound head wont move. The pressure pads move against it.
We will see what you report next Janice, and thanks to Pauls astute observation along with Steves earlier input, as well as Igors great idea, this is now closer to resolution.
dogtor frankarnstein
![[Roll Eyes]](rolleyes.gif) ![[Embarrassed]](redface.gif)
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At Projector Heaven the Focus is always on Detail.
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[o:/o]<|=- dogtor@projectorheaven.com.au
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Janice Glesser
Film Goddess
Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011
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posted February 05, 2012 11:22 AM
Hi all,
I really want to thank everyone for taking all this extra time and effort in helping me out. It is greatly appreciated. I apologize for my inability to communicate well at times and to understand what you guys are saying.
It would help me to just breakdown your last post Frank before I proceed. Some things are still a bit hazy for me in regards to what is working correctly and what is not. I need some simple yes and no answers ![[Smile]](smile.gif)
1. "...selector shaft needs to move back and not in the direction you were pushing it with the screwdriver. That is the wrong direction"
Ok...I was pushing with the screwdriver to try and open the chute. Obviously this was not correct or needed. So, the linkage is working properly in FORWARD (F) position...yes?
2. "You want the chute and sound head pads and the rollers that drives the flywheel to fully close when switched to forward/lamp/sound, so it must go in the other direction."
Ok...This I understand and this appears to be working properly...yes?
3. "It is in the off position that there should be maximum gap at the sound head."
Ok...This too I understand...however this is NOT happening. The chute and heads are not up in the OFF position. This I can see.
3."When you go to F, the gap will close a tiny, weeny bit but still be open. Then finally all gaps fully closed when switched to forward/lamp/sound."
Ok...I understand this, but starting from the OFF position where the heads are fully down, when put in FORWARD (F) there's no place to go.
4. "There is no need to lift the chute up high when hand testing it because it doesn't go that high when in operation. It has to only go high enough to lift the pressure pads off the sound head."
Ok...but there was no gap...I tried hand feeding the film and it would not go down the shoot. Although now I understand that the clearance doesn't have to be as much as I thought.
5. "try to set the tang back to where it was, it should be horizontal and level and then try threading again with straight film."
OK...I can do this. I hope I haven't misaligned that pivot rod. It was hard to bend just the tang without bending some of the rest. I tried straightening it out as much as possible..but it's not as straight as before ![[Frown]](frown.gif)
6. " I feel there may not have been anything wrong at all with the machine. The fault appears to have been the film curling excessively. Elmos don't like curly leaders at all."
OK???? Are you saying that all I need to do is put the machine back together and it will work fine, just watch the curl? What about the chute and sound heads not raising up in the OFF position? This is still not right or am I missing something?
I really can't proceed until I have an answer about the chute's position when OFF. If the linkage is working properly then is it the pivoting rod that is not correct? Perhaps there is something wrong with it? Could you please address this specifically...and I wish I had a picture of how the pivoting rod looks in the correct OFF position.
Thanks guys...I believe we're almost there
ADDED NOTE: I'm taking today off from the Elmo...It's Super Bowl Sunday and I need a break :-)
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Janice
"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).
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frank arnstein
Jedi Master Film Handler
Posts: 534
From: Gold Coast. Australia
Registered: Jan 2005
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posted February 06, 2012 10:01 PM
Hi Janice,
All of us here will continue to try to help you get this final bit right.
So check the following things and we will see what you find.....
When the Selector Knob is set to Forward/Lamp/Sound, The gap between the flywheel rollers will be fully closed. At that time, there should be about 1mm free play between the tang and the shute it lifts. Try to get that free play correct when re-straightening the bent tang.
When you think thats Ok, turn the selector knob back to F and see if there is a bit less than 1mm air gap between the 2 flywheel rollers.
At the same time, look at the gap between the sound head and its pressure pads. It should be just enough to slide a film through the gap.
If after all that, you see that the sound head gap isnt right and it needs fine resetting, do it by loosening the 2 tiny screws that hold the sound head in place. These 2 screws are on slotted holes so the tiny sound-head gap can be finely reset there by sliding it closer or away from the pressure pads then retightening.
Test by turning the selector back to Lamp/Sound On and look at the sound-head pressure pads to check that they are now fully closed and the tiny internal spring loading is fully compressed.
Those settings should make the machine thread Ok and the sound to work Ok.
So try again and we will continue to await your reports of any progress.
We don't give up easy in this forum and we keep trying even if it takes years.
Igor is a fine example of how determined we can be but don't get too close to him as he may bite if over-excited by the sight of your hands. He hasn't seen a woman for a long time and so you may need to wear gloves in any subsequent videos.
GRrrrrrrrrrrrrrrrrrr. Droooool. Slobber.... just listen to him...
No, No, Get back to the lab. Igor.......
What hump? You know what hump I am talking about.
dogtor frankarnstein
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[ February 06, 2012, 11:43 PM: Message edited by: frank arnstein ]
--------------------
At Projector Heaven the Focus is always on Detail.
____
[o:/o]<|=- dogtor@projectorheaven.com.au
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Paul Browning
Phenomenal Film Handler
Posts: 1006
From: West Midlands United Kingdom
Registered: Aug 2011
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posted February 07, 2012 10:38 AM
Hi Janice, i see from your recent update your not completely happy with this gap at the soundhead and feed rollers,but i agree with an earlier comment you made about wanting it right without any compromise.I have tried before to upload picture's to the site but without much success.I 'd like to see a square on picture of the lever and that sliding finger that suppose to be all the way across,i can get a picture of my st800 and compare it.I do think the last picture looked to be at an angle even on the video, it needs to be at 90degree's to the parts mating with the function switch at 12o'clock.I'm sorry you will have to dismantle it a bit to do this, and understand if you don't want to but,if your not upto takeing out the circuit board which you will need to do to get access to any mechanism behind it in order to lube it up.I have looked and you really carn't see anything with the circuit board attached it is an awkward job and fiddly.I agree with you in not wanting to bend the lever, but i also understand the help and info from the other members is with good intention.If all else fails here perhaps you can take off the lever and send it me i think i have solution that will allow me to set it up,and then return it to you so all you will need to do is to re attach to your machine and away you go with gap restored.Thanks to frank and all the other guy's for your kind comment's ,i feel sure were on the home straight now.
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UBBFriend: Email this page to someone!
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If the chute doesn't open fairly high then the film doesn't feed down through the guide...but rather runs over it. That linkage just needs to move over more (like I demonstrated in my last video) that would solve the problem.
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