8mm Forum: Elmo ST1200 Green guides plus more

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Posted by Graham Ritchie (Member # 559) on October 03, 2017, 11:52 PM:

Well folks I am on a roll at the moment before summer kicks in to finish catching up with this film stuff, if that's possible.

This ST1200 was my first Elmo that I bought second hand back in 1979, Its still my favorite, but has had little use over the last few years. Along with the GS1200 the ST1200 has been getting the once over at present.

I have been looking at the film path and discovered places where with wear scratching could occur. The first on the list was the green guide below the bottom loop that the film rubs against. I removed it and with a file made the groove deeper with only the extreme edges touching the film as it works it way around towards the sound head. This guide does get wear, but once fixed it will be fine for many many years.

The next thing I discovered was the sound head pressure roller was not freely turning, thinking it must be of an earlier type being totally flat..not a good idea, if it does not turn properly it will scuff the film image area. I came across another pressure roller, this time a different type from another ST1200. Note only the edges of this one are in contact with the film...much much better. If you own a ST1200, do have a look at this tiny rubber roller and make sure its free to turn.

The old flat one at the bottom of this picture shown removed..

Close up of the new one...

Another area of concern that owners should have a look at, is the bottom sprocket spring loaded guide. Where the film just goes in, can wear totally flat. The easy fix is to remove it and file say 2mm into the leading edge area of the groove, leaving high and dry the two extreme edges for the film to run on as it was before, also while you have it off, have look at the wear on the opposite side to see if that if it does need the same treatment.

Refitted..

I think I got on top of things regarding the ST1200, the only other thing I did was to change the lens holder to the later type, that is spring loaded internally onto the lens to give a much better/smoother focus control.

Posted by Mark Mander (Member # 340) on October 04, 2017, 01:52 AM:

Another fine job Graham and having the machine since 1979 is something as well,after all your efforts I'll definitely be checking all my Elmo's,Mark

Posted by frank arnstein (Member # 330) on October 05, 2017, 05:09 AM:

A fine job on the Elmos Graham..

I have only one concern and that is with the replacement sound pressure roller you have used. I think it was designed with a flat roller to ensure close sliding contact is maintained between the film sound track and the flat sound head pickup. The better the contact the better the magnetic pickup function.

With your replacement roller the even flat pressure of the film against the magnetic pickup has been lost and a small air gap can form if the film isn't being held flat against the pickup. I believe this could impact the output sound quality.

In most other situations the use of such a stepped roller could be OK to protect the film, but in this particular case I think only a flat roller should be used, if you are expecting excellent sound output from the amp.

It will be interesting to hear what others in the forum think about this particular Elmo mod. and the sound quality issue.

dogtor frankarnstein [Smile]

[ October 05, 2017, 07:15 AM: Message edited by: frank arnstein ]

Posted by Tom Photiou (Member # 130) on October 05, 2017, 06:18 AM:

Defiantly wear on the second sprocket guide will cause scratching as will the sound head pressure pads.
Fortunately, the second guides are items we bought several of when they were available, (and i dont sell them), and also recently had a new sound head pressure pad assembly fitted.
Ours is the HD graham, is yours the early 1200? [Wink]

Very good info here Graham, yours will soon be like new again.

Posted by Graham Ritchie (Member # 559) on October 05, 2017, 01:09 PM:

Thanks everyone.

Frank the replacement pressure roller came from another ST1200 and adjusting its vertical alignment to the sound head is done by adjusting the fore and aft position, by the little arm held on by two small screws that you can just see in the photo. What surprised me was how forgiving the the sound output is to its contact. When I ran a test film, I lifted that pressure roller completey off, the sound was still there but muffled, but when I dropped the lightly loaded spring roller back down on the film the sound output was full on big time and that was before I properly adjusted the alinement of the roller.

Tom I think old reliable [Smile]

must be one of the first ST1200 to come out, and at a guess around 1973 mark. When I bought it second hand in 1979, the previous owner had brought it back from the islands in the Pacific and it needed a new pre-amp and replacement rollers that the local shop selling it fitted. Its been great all these years and would never part with it [Smile]

Posted by Tom Photiou (Member # 130) on October 07, 2017, 02:40 AM:

44 years, all our projectors are quite amazing really when you think about. It has been said before by Steve Klare that cars, fridges washing machines etc just get replaced once they get past 5/8 years if they go wrong yet we all expect our projectors to keep going on and on without causing any problems just so we can continue to watch movies.
Its a great testimony to how good these machines were designed and with continual servicing, (until there are no more parts left anywhere), hopefully they will at least see us all through. [Wink]

Even more so when important threads like this, for ALL machines are put up for us all to learn. Unfortunatly, it only seems to be Elmo Eumig and Beaulie tips and guides that appear. Obviously these are the machines that appear to be the main players. [Wink]

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