8mm Forum: GS-1200 Differences

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Topic: GS-1200 Differences

Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted April 10, 2008 04:08 AM

From the many entries it appears that the Elmo GS-1200 is perhaps the most popular projector. Now that I have two I am posting this in particular reference to the lower loop (front facing and rear facing) and the colouring of switches.

The first projector I will refer to as OLD, the motor has a date of April 1978 and its number is 822369. The other, NEW, has a motor date of June 1985 and its number is 832168. The OLD has a loop which faces the screen, and the NEW has a bottom loop in the reverse position, i.e., facing to the left.

The OLD:-
1] Window for checking of voltage.
2] Loop former control faces towards screen.
3] Permanent shute from bottom gate to sound head.
4] Loop setter pivots near sound head.
5] Two record buttons have REC embossed in white.
6] Switches (up/down) end coloured.

The NEW:-
1] No window for voltage check.
2] Loop former control faces to left of operator.
3] Green plastic shute moves into position when threading lever pressed down.
4] Loop former assembly under gate.
5] Loop set lever is one piece and attached to pull-down cover.
6] Embossed two REC markings on switches not self-coloured.
7] Up/down switches have plain ends, i.e. not coloured.

Forum members will recall that the Movie Maker test report in March 1980 was critical of the projector's handling of cement joins in the lower loop and entry to the sound section. They said that they were in touch with Elmo about it.

Obviously Elmo did quite a lot to change the film path.

Does anybody know if the older models can be modified in the sound section and be brought up to date? Are the necessary parts still available?

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Maurice

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Kevin Faulkner
Film God

Posts: 4071
From: Essex UK
Registered: Jun 2003

posted April 10, 2008 08:10 AM

It would be possible to bring an earlier version up to the later spec but the parts are no longer available.

There were in fact 5 versions of the machine but 3 versions where there were major changes.

The motor date don't always give a clue to the date as I have seen early dated motors in later machines. I think the box the motors were in just simply got topped up with some of the older batches then at the bottom of the pile.
The record switch levers were embossed with white paint on and off during production as were the main silver switches.
These were hand built machines and I think it was a case of what was in the various bins of parts at the time.
The GS1200 was always supplied as either a region specific voltage (ie 100-120V or 220 -240V) version or a world wide version which has the window for the voltage selector.

Ver1 was obviously first production.

Ver2 had the take-up motors voltage changed along with the voltage tapping on the transformer and a small take-up control board added to the rewind motor. Both take-up tensions now fine adjustable.

Ver3 Input roller is now alloy and switches an extra circuit on the take-up control board to slow the motors in reverse projection. With small reels of film the take-up tension was too great for small reels but just right for 1200ft reels. Film path was changed to the same layout as the ST600 range of machines.
Ver4 take-up motors working voltage was changed again.

Ver5 New style take-up motors manufactured by Mitsubishi.

Ok some of these changes sort of overlapped a bit but that breaks it down into the various versions. There were other slight changes but these were mainly electrical.

Its obvious that Elmo had a lot of grief getting the take-up motors running smoothly and at the right tension and this is the area where there were the most changes.
On early machines you will see the film tensioner just after the capstan tends to move up and down more compared to the later machines.
My Xenon has the new style take-up motor and the pull on the film is very steady with very little movement on the tensioner. I think the earlier motors were a little juddery at slow speed.

Hope this clarifies the basic changes which took place in the history of the GS1200.

Kev.

--------------------
GS1200 Xenon with Elmo 1.0...great combo along with a 16-CL Xenon for that super bright white light.

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted April 10, 2008 09:19 AM

Hi Kevin

Thanks for interesting details. When did the bottom loop get changed?

Maurice

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Maurice

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Kevin Faulkner
Film God

Posts: 4071
From: Essex UK
Registered: Jun 2003

posted April 10, 2008 09:40 AM

Maurice, When Elmo changed to the film path layout of the ST600. The 600/180 has that loop which goes back towards the lamphouse.

The earlier film path with the forward loop is the same as the ST1200 series.

If you wanted to change a forward loop GS to a back loop version you would have to change the whole optical/shutter assembly which is why I said you cant really do that now unless you found a scrap later machine.

Kev.

Kev.

--------------------
GS1200 Xenon with Elmo 1.0...great combo along with a 16-CL Xenon for that super bright white light.

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Paul Adsett
Film God

Posts: 5003
From: USA
Registered: Jun 2003

posted April 10, 2008 03:51 PM

I must say, comparing my Version 1 and Version 3 machines, that the projector seems to operate much better with the backward lower loop on the later version. I have observed exactly the same thing that Kevin has just pointed out, namely that the film tensioner is rock steady on the version 3, but oscillates up and down on the version 1. This is presumably why the sound on my version 1 often has detectable WOW, whereas the version 3 seems to not have this problem.

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The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj

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Kevin Faulkner
Film God

Posts: 4071
From: Essex UK
Registered: Jun 2003

posted April 10, 2008 06:32 PM

Spot on Paul. The original machines with no motor control had a very jerky movement and as they progressed through the various mods Elmo managed to reduce the effect.

The very last motors which Elmo used are made by Mitsubishi. I will try to take some pics of these. But the noticeable difference is that the rewind speed is really fast. They are also very smooth when running at the slower speed for take-up of the film.

Kev.

--------------------
GS1200 Xenon with Elmo 1.0...great combo along with a 16-CL Xenon for that super bright white light.

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Simon McConway
Phenomenal Film Handler

Posts: 1085
From: Doncaster, UK
Registered: Jun 2004

posted April 11, 2008 04:45 AM

Maurice; where did you obtain your GS? I got mine when Hingston Films in Leighton Buzzard closed down.

Kevin; how much should I expect to pay for a GS Xenon?

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Clive Carmock
Film Handler

Posts: 69
From: London, UK
Registered: Feb 2005

posted May 23, 2008 05:51 PM

Were there Xenon versions for many of these iterations?

My GS1200 Xenon is, I think, a late series machine, but has an annoying omission in that it's missing the earthing strap that keeps the flywheel grounded. When I run an Optical film after a while static builds up and I can hear a cracking noise fromt he speakers. I think this is static causing small sparks which are picked up by the optical soundhead. I need to see if I can fit some form of earthign strap to fix this.

It is also the version that has the extra transformer to run the fan much faster.

Clive

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Kevin Faulkner
Film God

Posts: 4071
From: Essex UK
Registered: Jun 2003

posted May 23, 2008 06:03 PM

Mine without that extra transformer does have the earth strap and I dont get any static probs.

Where Elmo mounted that extra transformer for the fan means they had no room for the earthing strap [Frown]

That was a very late mod which I have not found any documentation for.

Dont think there is too much you can do about it.

Kev.

--------------------
GS1200 Xenon with Elmo 1.0...great combo along with a 16-CL Xenon for that super bright white light.

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Clive Carmock
Film Handler

Posts: 69
From: London, UK
Registered: Feb 2005

posted May 24, 2008 08:24 AM

Kev you are right -the transformer is right where the earthing strap is on my standard (mk1 ) GS1200 is placed.

However I was wondering about a large U lop of springy metal bolted to the chassis and then resting lightly against the end of the flywheel spindle

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Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

posted May 24, 2008 08:58 AM

I'm totally with Clive on this one. Can't imagine there's no room for a simple earthing strap. The doktor has spoken. [Big Grin]

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Call me Phoenix. *dusts off the ashes*

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted May 24, 2008 10:24 AM

Perhaps Elmo were following Bell & Howell whose 16mm sound projectors from 1962 onwards had a metal spring strip which was bolted to the frame and ran on the end of the flywheel shaft.

This I undersood was to earth any static which built up with the film running over the metal of the sound drum.

This is similar to today's cinemas which have earthed platters. A non-static spray is used on the face of the plates each morning, in addition to the earthing arrangement.

I once knew of one Chief projectionist who replaced the plastic rollers on his Christie units with brass ones. This totally cured his static problems.

Static not only causes sound problems but can accelerate the pick up of dust on the film, a great problem these days when over three hours of film are continually out in the open box (booth) as opposed to yesteryear when the 2000' spools lived in metal storage cabinets unless they were actually being run.

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Maurice

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Clive Carmock
Film Handler

Posts: 69
From: London, UK
Registered: Feb 2005

posted May 25, 2008 06:18 AM

It's definitely a shortcomign of that late series Xenon to leave the earthing strap out. Not find a source of springy thin metal strip!

I'll have a go and report back with pictures of how I get on.

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