GS-1200 far right frame line

[Burton Sundquist]

This question and solution is probably here in the Archive but I am asking again now. My first GS-1200 was fully modified with new guides and modified with the extra rollers where necessary. After a clean run a second screening shows an intermittent right side faint black line.
Not the green emulsion line associated, just a black hair thin line that comes and goes. Question is: what may be the cause? As mentioned, above sprocket parts are okay.
Thanks in advance for possible solutions.

[Graham Ritchie]

Hi Burton

Can you post some photos of your film paths? also what model of GS1200 is it. ie the bottom loop is it forward facing? or rear ward". The early GS1200 had a forward bottom loop they changed it to rearward I can think of. The result of the fwd facing bottom loop was wear as the loop goes round into the soundhead "the holder of the soundhead", also someone mentioned here, I can't remember who, did say he found that the four spring loaded pins that push the film onto the soundhead can cause edge scratching when worn flat, another place is the black film tensioner near the bottom sprocket, when that gets a flat on it, that also can cause scratching

As I say Burton, if you can take some close up photos that would be great

[Graham Sinden]

I had this problem years ago and it turned out to be the black tensioner. I tried reshaping it but then removed it completely. Burton was this part also changed to a roller.

[Burton Sundquist]

Graham, it is a MK 3, so rear facing loop. I also have a roller instead of tensioner. I narrowed the profile of the head presser pins so that they no longer contact the image area. The chrome sound head part doesn't look worn so I am thinking it is happening after the film enters the sound head area...

[Graham Ritchie]

Its a tricky one Burton, just a thought, how is the spring loaded green guide looking for wear around the bottom sprocket?, also when running a film, are the guides that are after the bottom sprocket, are not touching the film as it makes its way up to the rewind. I did notice with my GS1200 the take reel itself was out a bit out, due to those two tiny screws that hold the part that the reel slides onto on the take up arm itself had become a bit loose. After I tighten those two screws, the take up reel ran more in alignment with the film coming of that top chrome roller.

I would run some old test film and have a close look at everything, while the projector is running, and see if there is anything that does not look right.

[Burton Sundquist]

Thanks Graham, just where I was heading. I was going to remove the bottom spring loaded guide and get out my magnifier to look for possible wear spots. I will check the film path from there including the rollers whilst running a test print as well as checking the take-up reel for true-ness. I will also look closely at the sound head itself and the white guide there where the film exits. I will post a report as to my findings but I must add that your's and all replies are greatly appreciated and for that I am thankful!
. This GS-1200 is one of two I am fortunate to have, and I use it as my recording machine after installing a new recording capacitor. My second unit has all the modifications as well, but I usei it only for screening. It has never produced any lines or scratches. I ran test 200' reel through it 10 times and not a sign of lines or wear.
. The first machine has the very same modifications so there must be something happening out of the sound gate. I will find it and get back to you when I do. Thanks Again!

[Stuart Reid]

Could it be the metal sound head holder? I've just had a similar experience.

[Burton Sundquist]

Hi Stuart,
You are correct, this is an area where scratches can occur. I will look there again but I believe the metal shoulders on mine to be sufficient to eliminate that as the source of my right side line. You should remove your head presser part to have a good look at the metal sound head assembly of your machine. Removing that entry roller is one solution but not if you yours is a MK 1 machine with the forward facing loop. This has helped in prior posts. Others have filed the metal between the shoulders to stop the wear. Just be sure to have a good look at the two raised shoulders and that they don't look worn. Most likely a plastic guide issue or stalled roller causing this. I will let you know what I find in a few days.

[Graham Ritchie]

Hi Burton

Your welcome, hope you find the source.

[Mark Norton]

Couple of mods. Cut head pressers & filed back holder.

[Burton Sundquist]

Very good Mark, when you say "cut head pressers " what method did you use to change the profile of the presser pins? Nice work on the metal sound head holder. Did you remove the holder to file it? Another member performed this in situ which is not appropriate. You now have much more shoulder height than on mine. I will look there again. A very important area to keep an eye on for all GS-1200 owners.

[Mark Norton]

Hi Burton, the head pressers to the right (when looking from the front) are the ones to look out for, I removed them, trimmed with a scalpel & filed. Not too much of a steep angle or they will rotate when engaged. Take too much off & you will have low sound on that track. Just take your time.

While the head pressers & roller are out of the way It is possible to slowly file the head holder in place by use of a suitable small width file snapped to a short length & then polishing with a snake stone.

Another way is to use a recorded test tone film to make for accurate replacement of the sound heads after removal for work or replacement.

[Lee McCaffrey]

Burton, is this intermittent line to the far right of the frame a base or emulsion scratch? This will further narrow down the location of the scratch point.
If the scratch is an emulsion side line it may be possible to 'heal' it with water, there are a number of posts on the old archived forum about this. Otherwise a light base line should be easily treated with filmguard.

[Burton Sundquist]

Thanks Mark and Lee! I had the opportunity tonight to inspect everything and found what I think is the cause. This is a fine line, not an emulsion scratch which I saw under a magnifier after screening a reel. It presents on the screen as a thin black line at points and then just an impression. After removing and inspecting several parts I removed the white guide at the exit of the sound head and noticed it had worn flat on the main stripe side. I used a diamond file to create a deeper groove and build up the edge shoulders Everything else passed inspection so I think I am over it...Unless I see another line!

[Thomas Knappstein]

If there are intermittend Lines on the blank Side of the Film they can be made by this green Part on the upper Sprocket.
You can file ist deeper in the Middle (like on my Picture) or you assembled a second Roller into this Part, so there will never be any Scratches from there.
The Shoulders of the Sound Head Holder you can glue some new ones on there of hard Aluminium.