8mm Forum: GS 1200 Scratching?

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Posted by Brian Hendel (Member # 61) on September 24, 2007, 04:03 PM:

I'm noticing that certain prints I'm watching on my GS1200 are getting light hairline scratches that I didn't notice on the first screening. These are mostly used prints so maybe they were already scratched but I don't think so... I'm wondering if there's something I can check to see what's causing this. I'm assuming it's something that's happening after the film passes through the gate... Inspecting things this weekend I noticed that one of the back rollers on the film path (the one the film hits as it makes it's initial upward movement to the take up reel) is getting stuck so it's often not moving as the film passes over it... Perhaps that could be causing the scratches. Film cleaner temporarily removes most of the lines I'm seeing but I would like to eliminate the problem all together. I keep the projector very clean and use an air blower after every use... So it's frustrating.

Posted by Ugo Grassi (Member # 139) on September 25, 2007, 03:09 AM:

I talk about the scratches made by the GS1200 in this long italian article.
By a translator you could read it, I hope... http://www.laboratoriomilano.com/soffitta14.htm

Posted by Lee Mannering (Member # 728) on September 25, 2007, 03:51 AM:

Hello Brian and hope you are well.
My little note has nothing to do with the GS1200 but years ago I had trouble with a new and just out of the box GS800 scratching film. Upon return from service the agent changed the chrome chute for the film as it enters the sound heads. It was poor chrome work from Elmo that was scratching my films at that time, needless to say the Elmo crowd never answered my letter of complaint about the scratches the new GS800 had made to my valuable (at that time) films.

I wonder if it might be worth removing the green plastic guides around the top and lower sprockets to see if the gloss has worn away on your GS1200. Perhaps a good clean up with some Silicon may also help just in case some dirt has become lodged in a tight spot?

Hope something in the above is of help but I am not expert.

The very best to you..

Posted by Brian Hendel (Member # 61) on September 25, 2007, 04:34 PM:

Thanks for the tip Lee... I'll check that out this weekend and post if I have any luck.

Brian

Posted by Graham Ritchie (Member # 559) on September 27, 2007, 04:30 AM:

Brian
I would check back previous posts on this subject, its been well covered with some very interesting photos, and scratch free mods that forum members have carried out on there GS1200, not sure how far back you will have to go, but its back there somewhere.

Regards Graham. [Smile]

Posted by Brian Hendel (Member # 61) on October 13, 2007, 09:36 PM:

OK, this scratching problem with my GS1200 is getting worse. I took the green plastic film path parts out and cleaned them as well as I coukd and I also oiled up the silver roller that seemed to be getting stuck and I am still getting scratches. Over the last week I have put terrible lines in the middle of two of my favorite films. It's at the point where I'm afraid to watch anything. It's definitly something that's happening after it passes the gate. Could it be something in the sound head area? I'm afraid to mess with that too much for fear of screwing up the sound.

The lines are pretty much center of the image and are pretty significant but are black and not the deep, green emulsion lines. If anyone has any suggestions please let me know. It's really making me crazy! [Confused]

Posted by Joerg Niggemann (Member # 611) on October 14, 2007, 02:43 AM:

Brian, scratches in the middle of the film are a sign of heavy wear, misalignment or something stuck in the film path.

Critical points of wear after the gate are the entry of the sound head area with rubber roller (have a look at the chrome part under the roller) and the black plastic tensioner. The sound head itself could also damage your film if it is heavily worn, but I've never seen that on a GS. These heads seem to be quite durable. In general, all parts of the filmpath should touch the film only at the edges.

At the end of the filmpath, there's a point where misalignment could lead to scratching: Please follow Ugo's link and have a look at the last photo in his article. You can see the last silver roller before the film leaves the filmpath. This roller moves backwards under the takeup tension and releases the threading mechanism by pushing a micro switch. If the stop is adjusted incorrectly, the roller can move backwards too far and the film will run over the edge of the green filmpath plastic part (removed in the photo). You should simply run a film and have a look at the roller...

Joerg

Posted by Andrew Wilson (Member # 538) on October 14, 2007, 05:03 AM:

Sounds like the trouble i had until Mr.Elmo put it right.The gs1200
is well know for this problem,if has heavy usage,and the film path has to be kept a eye on,and clean at all times.This i think is more common with the version one of this machine,as Elmo improved the film path and tension on versions two and three.Andy.

Posted by Kevin Faulkner (Member # 6) on October 14, 2007, 05:45 AM:

Brian, it would be good to know what version of the GS 1200 you have. Does the film loop under the gate go back toward the lamp house or does it come out under the lens.

Also what I would do right now is find a clean unscratched piece of leader or film and run it through the machine for a few feet. Stop the machine and mark several key points on the film with say a china-graph pencil. Points like entrance to gate, exit from gate, entrance to sound head, pinch-roller, black tensioner etc etc. Remove the film manually and then study it to see at what precise point the scratching is taking place. Once you have determined that we will be able to better advise you.

How old is this machine and what sort of life has it led in terms of use? Also what is the sound quality like? For the heads to scratch there is often deterioration in sound as well.

Really the test above is the way forward and probably the only way to determine the correct course of action. Believe me for a machine to get this bad at scratching it really has to have had miles of film through it. If you can determine the area accurately make sure that there isn't a slither of film stuck in the path at that point.

Report back, Kev.

Posted by Brian Hendel (Member # 61) on October 14, 2007, 07:25 AM:

Kev - The model I have sends the film back towards the lamp house after the gate.

I have no idea how much mileage this projector has gotten before me but for the 8 years or so that I've had it I have kept it very clean. Just last year it was serviced for warbly sound (which I sometimes still notice slightly) and was told everything was fine with all the parts so I'm really not sure what's going on.

One thing that makes me think it is happening immediately after the gate or at the sound head is that when I put the clean film in rewind the scratch appears almost instantly it doesn't take a couple seconds to appear so it can't be happening all the way at one of the back rollers.

The grease pencil idea sounds like a good way to pinpoint the problem. I will try that as soon as I can. I will be away from the projector for a couple weeks but it will be the first thing I will do when I come back and will post my findings right away. I have to solve this before damaging another film and I'm sure I will need your help.

Thanks again, Brian

Posted by Kevin Faulkner (Member # 6) on October 14, 2007, 08:38 AM:

I'm sure that will help pin down the problem. You have one of the later machines so that is also good news.
Let us know what you find in due course.

Kev.

Posted by Mark Norton (Member # 165) on October 16, 2007, 04:33 AM:

Brian, on the chrome sound head holder under the black rubber roller, directly after the film exits the gate, are the shoulders worn down?
It's possible to carefully file down the the area between these shoulders with a very short cut down needle file ( leaving the heads in place, but removing the black roller and head presser for access). I think some have managed to build the worn metal back up, I have tried this in the past but it didn't work as well for me.
Hope this helps.

Posted by Kevin Faulkner (Member # 6) on October 16, 2007, 07:38 AM:

If the wear is at the entrance to head block and its that severe then the likelyhood is that the heads themselves will also have wear.

I have used this new product called Araldite Putty which goes extremely hard. It's supposed to be as hard as metal. You have 10mins to shape it in place and then you can file it to the correct profile etc.

Before we start worrying Brian lets see what he finds with the scratch test becase it could be the guide under the gate which goes back towards the lamp house. It could also be the swinging tensioner.

What I didnt ask Brian was is the scratch on the base or emulsion side of the film?

Kev.

Posted by Brian Hendel (Member # 61) on October 16, 2007, 12:43 PM:

I'm away from my projector and films... but the scratches don't seem to be deep emulsion scratches because they aren't green... they are thin and black and seem to be towards the center of the image. Does that give any clues to anything? Again, I won't be able to do any tests for the next few days.

Posted by Kevin Faulkner (Member # 6) on October 16, 2007, 04:40 PM:

Yes that would suggest base scratches and could be the head entrance as Mark suggested but it could also be the black swinging tensioner.

Do the test I suggested earlier when you are back home and lets see what it reveals.

Kev.

Posted by Brian Hendel (Member # 61) on October 28, 2007, 12:00 PM:

Kev - Need a little more advice on the scratcing problem. That test is tricky to do because it's not doing it on all films. So of course when I tried it there was no scratch at all but when I watched another film it started up again. You never know when it's going to strike to it's tough to pinpoint. But I'm sure it's right after the film gate because as I said when I put it in reverse the scratch shows up instantly. So... is there something I can look for to tell if there is a problem with any of the parts right after the gate (ie the entrance to the sound heads or the black plastic tensioner? Everything looks fine and smooth to me with no wear so it's really baffling me. Is there a chance the pressure pad right below the gate is too tight and needs to be loosened? I didn't want to mess with that without asking...

I have another little problem. I have to keep the internal speaker disconnected because there's a loud popping noise. It's not there on any of the speaker output jacks so I'm assuming it's not something happening with the actual sound heads. It's not a huge problem because I can keep it disconnected since it's going through an external sound system anyway, but it's still a little annoying.

Sorry for all the questions. You should probably be sending me a consultation bill!

Posted by Paul Adsett (Member # 25) on October 28, 2007, 01:42 PM:

Brian,
The new 'Armchair Odeons' DVD has an in-depth discussion by Dave Locke on solutions to scratching problems in the GS1200.

Posted by Brian Hendel (Member # 61) on October 28, 2007, 01:44 PM:

Paul - That's another reason I'm glad I just ordered a copy!
Brian

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